Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Steve Malikoff via cctalk]

Tom said
> On 6/17/21 6:57 AM, Steve Malikoff via cctalk wrote:
>> Tom said
>>> I have a couple different drawing sets for the 11/05 and while some have 
>>> the matching M7260
>>> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
>>> schematic:
>>>
>>> http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
>>>
>>> The GT40 drawings has the PROM listings and related, so I am hoping that 
>>> they match what is in the
>>> two boards.
>> My original PDP-11/05 print set that came from the BHP steelworks is titled 
>> just 'PDP-11/05 Engineering
>> Drawings' and the drawings are for machine revision 1105-0. It covers the 
>> early 11/05 with the cast metal
>> grille with no slots (as seen in the 11/05 handbook) rather than the later 
>> 11/05 with the plastic slotted
>> grille.
>> The dates on the drawings are 1972 and some of the microcode listing dates 
>> are different to the 'PDP-11/05-S,
>> 11/10-S systems engineering drawings' bitsavers scan and the GT-40 scan, and 
>> some of them are the same.
>>
>> I'm not sure where I look to see what revision of the M7261 it shows, as the 
>> Rev box in the bottom right
>> seems to jump around, eg. Rev N, Rev K, Rev H or is that just the minor 
>> drawing revision for that page?
>>
>> Steve
>>
> If you look at the board layout for the M7261, the E rev board has a large 
> open area, devoid of ICs,
> whereas
> the non-E rev board has a uniform distribution of ICs across the surface.
>
> --tom
>

Yes my M7261 board drawing appears to be the earlier one, similar to the GT40 
drawing but is
revision N instead of M. (I myself have an early 11/05 s/n 151 but it has a 
later M7261 in it.)

>From the ex-BHP print set the microcode listing details and Page Revision 
>Control Sheet latests are


K-MP-KD11-B-1   MICROPROGRAM FLOW   Rev B
(PRCS: Rev. B [BABAAA]) (Listing: K-MP-KD-11B-1 Rev. A 
27-JUL-72)

K-MP-KD11-B-2   MICROPROGRAM SYMBOLIC LISTING   Rev D
(PRCS: Rev. D [DABCBA]) (Listing: K-MP-KD-11B-2 Rev. A 
27-JUL-72)

K-MP-KD11-B-3   MICROPROGRAM BINARY LISTING Rev D
(PRCS: Rev. D [DAA])(Listing: K-MP-KD-11B-3 Rev. A 
27-JUL-72)

K-MP-KD11-B-4   MICROPROGRAM CROSS REF LISTING  Rev D
(PRCS: Rev. -)  (Listing: K-MP-KD-11B-4 Rev. * 2-MAY-72)


M7620-0-1   DATA PATHS  Rev. N
(PRCS: Rev. N [MMMN])

M7260-0-8   DATA PATH ROM PATTERNS  Rev. ? (same as GT40)

M7261-0-1 CONTROL LOGIC AND MICROPROGRAMRev. P
(PRCS: Rev. P [PNHHJKJHJMKKKH])

M7261-0-1 CONTROL LOGIC ROM PATTERNSRev. A (same as GT40)
(PRCS: Rev. A [A])

Steve.

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

On 6/17/21 6:57 AM, Steve Malikoff via cctalk wrote:
> Tom said
>> I have a couple different drawing sets for the 11/05 and while some have the 
>> matching M7260
>> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
>> schematic:
>>
>> http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
>>
>> The GT40 drawings has the PROM listings and related, so I am hoping that 
>> they match what is in the
>> two boards.
> My original PDP-11/05 print set that came from the BHP steelworks is titled 
> just 'PDP-11/05 Engineering
> Drawings' and the drawings are for machine revision 1105-0. It covers the 
> early 11/05 with the cast metal
> grille with no slots (as seen in the 11/05 handbook) rather than the later 
> 11/05 with the plastic slotted
> grille.
> The dates on the drawings are 1972 and some of the microcode listing dates 
> are different to the 'PDP-11/05-S,
> 11/10-S systems engineering drawings' bitsavers scan and the GT-40 scan, and 
> some of them are the same.
>
> I'm not sure where I look to see what revision of the M7261 it shows, as the 
> Rev box in the bottom right
> seems to jump around, eg. Rev N, Rev K, Rev H or is that just the minor 
> drawing revision for that page?
>
> Steve
>
If you look at the board layout for the M7261, the E rev board has a large open 
area, devoid of ICs,
whereas
the non-E rev board has a uniform distribution of ICs across the surface.

--tom

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Steve Malikoff via cctalk]

Tom said
> I have a couple different drawing sets for the 11/05 and while some have the 
> matching M7260
> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
> schematic:
>
> http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
>
> The GT40 drawings has the PROM listings and related, so I am hoping that they 
> match what is in the
> two boards.

My original PDP-11/05 print set that came from the BHP steelworks is titled 
just 'PDP-11/05 Engineering
Drawings' and the drawings are for machine revision 1105-0. It covers the early 
11/05 with the cast metal
grille with no slots (as seen in the 11/05 handbook) rather than the later 
11/05 with the plastic slotted
grille.
The dates on the drawings are 1972 and some of the microcode listing dates are 
different to the 'PDP-11/05-S,
11/10-S systems engineering drawings' bitsavers scan and the GT-40 scan, and 
some of them are the same.

I'm not sure where I look to see what revision of the M7261 it shows, as the 
Rev box in the bottom right
seems to jump around, eg. Rev N, Rev K, Rev H or is that just the minor drawing 
revision for that page?

Steve

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Guy Sotomayor via cctalk]

On 6/15/21 12:16 PM, Tom Uban via cctalk wrote:

On 6/15/21 2:02 PM, Josh Dersch wrote:

Just to provide some real-world data, I used a pair of KM11's to debug my 
11/05, see the picture here:

http://yahozna.dyndns.org/scratch/1105-debug.jpg 


They worked fine.  (These are clones, from Guy Sotomayor's kit.)  I can verify 
tonight whether I
have the earlier or later rev CPU set, if that helps.

- Josh


Interesting! From your pic, you have the M7260 without the circular baud rate 
selector switch, but I
cannot tell which M7261 board you have.

Does the machine come up and run normally with the boards in and the switches 
all the disabled
positions or do you have to do a special sequence to start?

I will have to look at the schematics to see how the two slots connect to the 
processor on each of
the board versions and maybe also take a look at Guy's KL11 schematic if it is 
on his site.


The schematic should be in the user's manual for the KM11.

--

TTFN - Guy

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

On 6/15/21 2:02 PM, Josh Dersch wrote:
>
>
> On Mon, Jun 14, 2021 at 10:34 PM Tom Uban via cctalk  > wrote:
>
> On 6/14/21 3:39 PM, Noel Chiappa via cctalk wrote:
> >     > From: Tom Uban
> >
> >     > it has the early version M7261E Control Logic & Microprogram 
> board and
> >     > the later version M7260 Data Paths board
> >
> > Ah, I'm glad someone found all that stuff I wrote up there useful. As 
> always,
> > I _think_ I got it all transcribed correctly, but do be on the lookout 
> for
> > errors!
> I most certainly did - thank you for creating it!
> >     > it seems like an older/newer combination, but maybe that was 
> common. I
> >     > would not have guessed that the four possible combinations would 
> all
> >     > work together, but maybe they do?
> >
> > I honestly don't know. As far as I can tell, the DEC documentation 
> doesn't
> > even _mention_ the two different board generations; perhaps a sign that 
> they
> > are functionally interchangeable? (Although even the section on baud 
> rate, in
> > both DEC-11-HKDBB-A-D and EK-KD11B-MM-001, 4.11, doesn't even mention 
> the
> > early board. So maybe the manual just ignores the earlier version 
> completely?)
> >
> > I don't have an /05 up and running at the moment, or I'd check all 4 
> and see
> > if they all work.
> >
> >     > Presently, the machine sometimes runs relatively well and other 
> times
> >     > it does not.
> >
> > What are the failure symptoms? (It's almost certainly going to take a 
> 'scope
> > to fix it; I expect you have one?)
> I have KM11s, a scope, a logic analyzer, a unibone, shiresoft unibus 
> analyzer, etc.
> No shortage of gear, just a shortage of time.
> > I'd start by monitoring the CPU clock, and make sure it's running when 
> the
> > failure happens. (Note that the front console is handled by the 
> microcode, so
> > if the microcode isn't running, the machine will be totally dead.
> > EK-KD11B-MM-001 has a good description of how that works.)
> I think I checked the clock when I started this project a while back, but 
> I will
> check it again. Unfortunately, I haven't figured out how to provoke two 
> states,
> but it mostly picks the completely dysfunctional state, so I'll look at 
> the clock.
> >     > my initial messing with KM11 boards, reveals that I can step the
> >     > microcode with a KM11 in either the #1 or #2 position, but when 
> two
> >     > KM11s are installed at the same time, they do not function 
> properly
> >     > together. Is this expected or do I have an issue there too?
> >
> > Not sure. EK-KD11B-MM-001 (available at:
> >
> >   http://www.bitsavers.org/pdf/dec/pdp11/1105/EK-KD11B-MM-001_Jan75.pdf
> 
> >
> > and definitely something you need) says, at pg. 5-6 "KM11 switches have 
> the
> > same function in slots KM-1 and KM-2", and on 5-7 "permits the user who 
> has
> > only one KM11 to plug into either KM-1 or KM-2".
> >
> > So that _sounds_ like you should be able to plug two in together. The 
> first
> > indicates that the switches, the only input to the KD11-B from the 
> KM11, are
> > wired in parallel, and the only other thing on the KM11 are the lights,
> > outputs. And why mention "user who has only one KM11", if having two is 
> no
> > use because one can't use two at once?
> I've read that doc, but did not come away with the impression that both
> can be used at the same time or not.
>
>
> Just to provide some real-world data, I used a pair of KM11's to debug my 
> 11/05, see the picture here:
>
> http://yahozna.dyndns.org/scratch/1105-debug.jpg 
> 
>
> They worked fine.  (These are clones, from Guy Sotomayor's kit.)  I can 
> verify tonight whether I
> have the earlier or later rev CPU set, if that helps.
>
> - Josh
>
Interesting! From your pic, you have the M7260 without the circular baud rate 
selector switch, but I
cannot tell which M7261 board you have.

Does the machine come up and run normally with the boards in and the switches 
all the disabled
positions or do you have to do a special sequence to start?

I will have to look at the schematics to see how the two slots connect to the 
processor on each of
the board versions and maybe also take a look at Guy's KL11 schematic if it is 
on his site.

--tnx
--tom

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Josh Dersch via cctalk]

On Mon, Jun 14, 2021 at 10:34 PM Tom Uban via cctalk 
wrote:

> On 6/14/21 3:39 PM, Noel Chiappa via cctalk wrote:
> > > From: Tom Uban
> >
> > > it has the early version M7261E Control Logic & Microprogram board
> and
> > > the later version M7260 Data Paths board
> >
> > Ah, I'm glad someone found all that stuff I wrote up there useful. As
> always,
> > I _think_ I got it all transcribed correctly, but do be on the lookout
> for
> > errors!
> I most certainly did - thank you for creating it!
> > > it seems like an older/newer combination, but maybe that was
> common. I
> > > would not have guessed that the four possible combinations would
> all
> > > work together, but maybe they do?
> >
> > I honestly don't know. As far as I can tell, the DEC documentation
> doesn't
> > even _mention_ the two different board generations; perhaps a sign that
> they
> > are functionally interchangeable? (Although even the section on baud
> rate, in
> > both DEC-11-HKDBB-A-D and EK-KD11B-MM-001, 4.11, doesn't even mention the
> > early board. So maybe the manual just ignores the earlier version
> completely?)
> >
> > I don't have an /05 up and running at the moment, or I'd check all 4 and
> see
> > if they all work.
> >
> > > Presently, the machine sometimes runs relatively well and other
> times
> > > it does not.
> >
> > What are the failure symptoms? (It's almost certainly going to take a
> 'scope
> > to fix it; I expect you have one?)
> I have KM11s, a scope, a logic analyzer, a unibone, shiresoft unibus
> analyzer, etc.
> No shortage of gear, just a shortage of time.
> > I'd start by monitoring the CPU clock, and make sure it's running when
> the
> > failure happens. (Note that the front console is handled by the
> microcode, so
> > if the microcode isn't running, the machine will be totally dead.
> > EK-KD11B-MM-001 has a good description of how that works.)
> I think I checked the clock when I started this project a while back, but
> I will
> check it again. Unfortunately, I haven't figured out how to provoke two
> states,
> but it mostly picks the completely dysfunctional state, so I'll look at
> the clock.
> > > my initial messing with KM11 boards, reveals that I can step the
> > > microcode with a KM11 in either the #1 or #2 position, but when two
> > > KM11s are installed at the same time, they do not function properly
> > > together. Is this expected or do I have an issue there too?
> >
> > Not sure. EK-KD11B-MM-001 (available at:
> >
> >   http://www.bitsavers.org/pdf/dec/pdp11/1105/EK-KD11B-MM-001_Jan75.pdf
> >
> > and definitely something you need) says, at pg. 5-6 "KM11 switches have
> the
> > same function in slots KM-1 and KM-2", and on 5-7 "permits the user who
> has
> > only one KM11 to plug into either KM-1 or KM-2".
> >
> > So that _sounds_ like you should be able to plug two in together. The
> first
> > indicates that the switches, the only input to the KD11-B from the KM11,
> are
> > wired in parallel, and the only other thing on the KM11 are the lights,
> > outputs. And why mention "user who has only one KM11", if having two is
> no
> > use because one can't use two at once?
> I've read that doc, but did not come away with the impression that both
> can be used at the same time or not.
>

Just to provide some real-world data, I used a pair of KM11's to debug my
11/05, see the picture here:

http://yahozna.dyndns.org/scratch/1105-debug.jpg

They worked fine.  (These are clones, from Guy Sotomayor's kit.)  I can
verify tonight whether I have the earlier or later rev CPU set, if that
helps.

- Josh

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

On 6/15/21 1:45 PM, Tony Duell wrote:
> On Tue, Jun 15, 2021 at 4:47 PM Tom Uban  wrote:
>> On 6/15/21 8:58 AM, Tony Duell via cctalk wrote:
>>> On Tue, Jun 15, 2021 at 6:34 AM Tom Uban via cctalk
>>>  wrote:
>>>
 My KM11s are based on Tony Duell's schematic and if you look, switches S3
 and S4 are both driving outputs rather than simply switching them to 
 ground,
 so I don't think two boards at one time would work if these signals are 
 simply
 tied in parallel on slots A2 and B2.
>>> I took the switch circuits from the offical KM11 schematics which are
>>> either in the PDP11/45 CPU printset or the RK11-C printset that I
>>> have, I forget which. I certainly didn't add logic or replace
>>> open-collector parts with totem-pole ones.
>>>
>>> -tony
>> I did not mean to imply that you had changed the behavior in your KM11 
>> design.
>> You are surely a competent and trusted pdp11 resource :)
>>
> I didn't mean to imply anythimg like that either. I was just
> confirming that my KM11-a-like and a real one will behave the same
> way, so if my version can't be used in pairs in an11/05, then the real
> one can't either.. I've been involved with classic computers for long
> enough to know that sometimes clones are not exactly identical to the
> real thing.
>
> I do have a pair of real KM11s now. Each is a pair of boards that plug
> together. The board that goes into the machine's backplane is discrete
> transistor lamp drivers, the one that plugs into it (and thus sticks
> out of the cardcage) contains the lamps, switches and ICs for the
> switch circuitry. I know where they are if you want me to confirm the
> IC numbers or whatever.
>
> -tony
Thank you for your offer, but I have one original KM11 (set) as well,
but it is not functional. I think the transistors on the extender half have
been mashed to many times and it is low in my priority list to fix as I
have to of my own "reproduction" boards.

--tom

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tony Duell via cctalk]

On Tue, Jun 15, 2021 at 4:47 PM Tom Uban  wrote:
>
> On 6/15/21 8:58 AM, Tony Duell via cctalk wrote:
> > On Tue, Jun 15, 2021 at 6:34 AM Tom Uban via cctalk
> >  wrote:
> >
> >> My KM11s are based on Tony Duell's schematic and if you look, switches S3
> >> and S4 are both driving outputs rather than simply switching them to 
> >> ground,
> >> so I don't think two boards at one time would work if these signals are 
> >> simply
> >> tied in parallel on slots A2 and B2.
> > I took the switch circuits from the offical KM11 schematics which are
> > either in the PDP11/45 CPU printset or the RK11-C printset that I
> > have, I forget which. I certainly didn't add logic or replace
> > open-collector parts with totem-pole ones.
> >
> > -tony
> I did not mean to imply that you had changed the behavior in your KM11 design.
> You are surely a competent and trusted pdp11 resource :)
>

I didn't mean to imply anythimg like that either. I was just
confirming that my KM11-a-like and a real one will behave the same
way, so if my version can't be used in pairs in an11/05, then the real
one can't either.. I've been involved with classic computers for long
enough to know that sometimes clones are not exactly identical to the
real thing.

I do have a pair of real KM11s now. Each is a pair of boards that plug
together. The board that goes into the machine's backplane is discrete
transistor lamp drivers, the one that plugs into it (and thus sticks
out of the cardcage) contains the lamps, switches and ICs for the
switch circuitry. I know where they are if you want me to confirm the
IC numbers or whatever.

-tony

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

On 6/15/21 8:58 AM, Tony Duell via cctalk wrote:
> On Tue, Jun 15, 2021 at 6:34 AM Tom Uban via cctalk
>  wrote:
>
>> My KM11s are based on Tony Duell's schematic and if you look, switches S3
>> and S4 are both driving outputs rather than simply switching them to ground,
>> so I don't think two boards at one time would work if these signals are 
>> simply
>> tied in parallel on slots A2 and B2.
> I took the switch circuits from the offical KM11 schematics which are
> either in the PDP11/45 CPU printset or the RK11-C printset that I
> have, I forget which. I certainly didn't add logic or replace
> open-collector parts with totem-pole ones.
>
> -tony
I did not mean to imply that you had changed the behavior in your KM11 design.
You are surely a competent and trusted pdp11 resource :)

--tom

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Bill Degnan via cctalk]

While we are on the subject of pdp11/05's I am in the need of repair
services for my M7261 KD11-B CPU board 1

(CONTROL LOGIC & MICROPROGRAMMED MODULE.)

Bill

On Tue, Jun 15, 2021, 9:59 AM Tony Duell via cctalk 
wrote:

> On Tue, Jun 15, 2021 at 6:34 AM Tom Uban via cctalk
>  wrote:
>
> > My KM11s are based on Tony Duell's schematic and if you look, switches S3
> > and S4 are both driving outputs rather than simply switching them to
> ground,
> > so I don't think two boards at one time would work if these signals are
> simply
> > tied in parallel on slots A2 and B2.
>
> I took the switch circuits from the offical KM11 schematics which are
> either in the PDP11/45 CPU printset or the RK11-C printset that I
> have, I forget which. I certainly didn't add logic or replace
> open-collector parts with totem-pole ones.
>
> -tony
>

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tony Duell via cctalk]

On Tue, Jun 15, 2021 at 6:34 AM Tom Uban via cctalk
 wrote:

> My KM11s are based on Tony Duell's schematic and if you look, switches S3
> and S4 are both driving outputs rather than simply switching them to ground,
> so I don't think two boards at one time would work if these signals are simply
> tied in parallel on slots A2 and B2.

I took the switch circuits from the offical KM11 schematics which are
either in the PDP11/45 CPU printset or the RK11-C printset that I
have, I forget which. I certainly didn't add logic or replace
open-collector parts with totem-pole ones.

-tony

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

On 6/14/21 3:39 PM, Noel Chiappa via cctalk wrote:
> > From: Tom Uban
>
> > it has the early version M7261E Control Logic & Microprogram board and
> > the later version M7260 Data Paths board
>
> Ah, I'm glad someone found all that stuff I wrote up there useful. As always,
> I _think_ I got it all transcribed correctly, but do be on the lookout for
> errors!
I most certainly did - thank you for creating it!
> > it seems like an older/newer combination, but maybe that was common. I
> > would not have guessed that the four possible combinations would all
> > work together, but maybe they do?
>
> I honestly don't know. As far as I can tell, the DEC documentation doesn't
> even _mention_ the two different board generations; perhaps a sign that they
> are functionally interchangeable? (Although even the section on baud rate, in
> both DEC-11-HKDBB-A-D and EK-KD11B-MM-001, 4.11, doesn't even mention the
> early board. So maybe the manual just ignores the earlier version completely?)
>
> I don't have an /05 up and running at the moment, or I'd check all 4 and see
> if they all work.
>
> > Presently, the machine sometimes runs relatively well and other times
> > it does not.
>
> What are the failure symptoms? (It's almost certainly going to take a 'scope
> to fix it; I expect you have one?)
I have KM11s, a scope, a logic analyzer, a unibone, shiresoft unibus analyzer, 
etc.
No shortage of gear, just a shortage of time.
> I'd start by monitoring the CPU clock, and make sure it's running when the
> failure happens. (Note that the front console is handled by the microcode, so
> if the microcode isn't running, the machine will be totally dead.
> EK-KD11B-MM-001 has a good description of how that works.)
I think I checked the clock when I started this project a while back, but I will
check it again. Unfortunately, I haven't figured out how to provoke two states,
but it mostly picks the completely dysfunctional state, so I'll look at the 
clock.
> > my initial messing with KM11 boards, reveals that I can step the
> > microcode with a KM11 in either the #1 or #2 position, but when two
> > KM11s are installed at the same time, they do not function properly
> > together. Is this expected or do I have an issue there too?
>
> Not sure. EK-KD11B-MM-001 (available at:
>
>   http://www.bitsavers.org/pdf/dec/pdp11/1105/EK-KD11B-MM-001_Jan75.pdf
>
> and definitely something you need) says, at pg. 5-6 "KM11 switches have the
> same function in slots KM-1 and KM-2", and on 5-7 "permits the user who has
> only one KM11 to plug into either KM-1 or KM-2".
>
> So that _sounds_ like you should be able to plug two in together. The first
> indicates that the switches, the only input to the KD11-B from the KM11, are
> wired in parallel, and the only other thing on the KM11 are the lights,
> outputs. And why mention "user who has only one KM11", if having two is no
> use because one can't use two at once?
I've read that doc, but did not come away with the impression that both
can be used at the same time or not.
My KM11s are based on Tony Duell's schematic and if you look, switches S3
and S4 are both driving outputs rather than simply switching them to ground,
so I don't think two boards at one time would work if these signals are simply
tied in parallel on slots A2 and B2.

Alas, using only one KM11 at a time is fine and I will be able to make progress
in that way.

--tom

>   Noel

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Noel Chiappa via cctalk]

> From: Tom Uban

> it has the early version M7261E Control Logic & Microprogram board and
> the later version M7260 Data Paths board

Ah, I'm glad someone found all that stuff I wrote up there useful. As always,
I _think_ I got it all transcribed correctly, but do be on the lookout for
errors!

> it seems like an older/newer combination, but maybe that was common. I
> would not have guessed that the four possible combinations would all
> work together, but maybe they do?

I honestly don't know. As far as I can tell, the DEC documentation doesn't
even _mention_ the two different board generations; perhaps a sign that they
are functionally interchangeable? (Although even the section on baud rate, in
both DEC-11-HKDBB-A-D and EK-KD11B-MM-001, 4.11, doesn't even mention the
early board. So maybe the manual just ignores the earlier version completely?)

I don't have an /05 up and running at the moment, or I'd check all 4 and see
if they all work.

> Presently, the machine sometimes runs relatively well and other times
> it does not.

What are the failure symptoms? (It's almost certainly going to take a 'scope
to fix it; I expect you have one?)

I'd start by monitoring the CPU clock, and make sure it's running when the
failure happens. (Note that the front console is handled by the microcode, so
if the microcode isn't running, the machine will be totally dead.
EK-KD11B-MM-001 has a good description of how that works.)

> my initial messing with KM11 boards, reveals that I can step the
> microcode with a KM11 in either the #1 or #2 position, but when two
> KM11s are installed at the same time, they do not function properly
> together. Is this expected or do I have an issue there too?

Not sure. EK-KD11B-MM-001 (available at:

  http://www.bitsavers.org/pdf/dec/pdp11/1105/EK-KD11B-MM-001_Jan75.pdf

and definitely something you need) says, at pg. 5-6 "KM11 switches have the
same function in slots KM-1 and KM-2", and on 5-7 "permits the user who has
only one KM11 to plug into either KM-1 or KM-2".

So that _sounds_ like you should be able to plug two in together. The first
indicates that the switches, the only input to the KD11-B from the KM11, are
wired in parallel, and the only other thing on the KM11 are the lights,
outputs. And why mention "user who has only one KM11", if having two is no
use because one can't use two at once?

Noel

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Jay Logue via cctalk]

No need to convert current loop, as the outputs from the 11/05 console 
are (roughly) TTL compatible.  All you need is a level shifter such as a 
MAX232 and an inverter (although this will only give you 2400 baud max).


I built a simple console to USB adapter using a Teensy that works quite 
well if you're interfacing with a terminal program running on a modern 
computer.  With this you can run up to 38400 baud. Details are here: 
https://github.com/jaylogue/pdp-1105-console-usb-adapter 



--Jay

On 6/14/2021 9:14 AM, Tom Uban wrote:

I'm not to the point of connecting serial yet, but I did see this page which 
will help me turn the
current loop to rs232 when the time comes:
http://retrocmp.com/how-tos/interfacing-to-a-pdp-1105

--tom

On 6/14/21 10:37 AM, Jay Logue via cctalk wrote:

I also have an 11/05 with the early CPU boards that exhibited stuck bits on 
arrival.  Turned out
to be bad transistors in the inhibit circuits on the G110.  Pretty easy fix 
once I tracked it
down. So far I've found the GT40 print set to be a fairly accurate, at least 
for the boards I have.

I'll be curious to learn how your serial console works.  Mine had a 
manufacturing defect that had
to be corrected before input would work.

--Jay

On 6/13/2021 1:44 PM, Tom Uban via cctalk wrote:

I am working on the first of my two 11/05s. Interestingly, it has the early 
version M7261E Control
Logic & Microprogram board and the later version M7260 Data Paths board (with 
circular baud rate
selector switch) as described in:

http://gunkies.org/wiki/KD11-B_CPU

  From the description there, it seems like an older/newer combination, but 
maybe that was common. I
would not have guessed that the four possible combinations would all work 
together, but maybe
they do?

I have a couple different drawing sets for the 11/05 and while some have the 
matching M7260
schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
schematic:

http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf

The GT40 drawings has the PROM listings and related, so I am hoping that they 
match what is in the
two boards.

Presently, the machine sometimes runs relatively well and other times it does 
not. It does have bit
1 stuck ON in memory, but that should be a relatively simple task to diagnose 
as it is not
intermittent. When the machine is "working" I am able to deposit 0777 at 0100 
and run. When running
this simple program, I've experimented with flexing the boards and such, so it 
doesn't seem like an
obvious poor connection, but that remains to be seen.

The machine is a configuration #2 model (as described in the "gunkies" site) 
and my initial messing
with KM11 boards, reveals that I can step the microcode with a KM11 in either 
the #1 or #2 position,
but when two KM11s are installed at the same time, they do not function 
properly together. Is this
expected or do I have an issue there too?

Thanks much to those who have provided details and documents on the web, they 
have already been of
great value and will most certainly continue to be a resource in the future.

More updates in the future...

--tom

On 5/6/16 5:32 PM, Noel Chiappa wrote:

  > From: Mattis Lind

  > Thanks Noel for sorting this out.

Eh, de nada. But thank you.


  >> I wonder if the ucode in the two versions is identical? The uROM chip
  >> numbers should give it, (if they are the same on both versions, albeit
  >> in different locations on the board), but I have yet to check. Does
  >> anyone happen to know?

OK, so the situation here is pretty complicated. To start with / make things
worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of PROMs.

For the data paths board (M7260), both major versions appear to contain the
same PROMs (going by the DEC part numbers), but the chip location (Exx)
numbers are all different.

For the control board (M7261), the C, E ('early' version) and F ('late'
version) etch revisions each contain mostly the same PROMs, but apparently
with slight differences between the sets of PROMs in each (as reflected in
different DEC part numbers). For details see:

    http://gunkies.org/wiki/PDP-11/05#Control_PROMs

to which I have just added all the gory details.

As to getting the contents of all of them dumped in machine-readable form -
oi vey!


  >> on the earlier version (prints for that version are in the GT40 prints
  >> online

It turns out that I have hard-copy prints for the "C" etch revision of the
M7261, which do not yet appear to be online; the GT40 prints have the "E"
etch revision.

I will scan the pages for that revision of the board, and put them up 'soon'.
(I'm not doing the whole print set, it's about 1" thick, and most of them are
for other things anyway, like MM11-L memory, etc.)

 Noel

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

I'm not to the point of connecting serial yet, but I did see this page which 
will help me turn the
current loop to rs232 when the time comes:
http://retrocmp.com/how-tos/interfacing-to-a-pdp-1105

--tom

On 6/14/21 10:37 AM, Jay Logue via cctalk wrote:
> I also have an 11/05 with the early CPU boards that exhibited stuck bits on 
> arrival.  Turned out
> to be bad transistors in the inhibit circuits on the G110.  Pretty easy fix 
> once I tracked it
> down. So far I've found the GT40 print set to be a fairly accurate, at least 
> for the boards I have.
>
> I'll be curious to learn how your serial console works.  Mine had a 
> manufacturing defect that had
> to be corrected before input would work.
>
> --Jay
>
> On 6/13/2021 1:44 PM, Tom Uban via cctalk wrote:
>> I am working on the first of my two 11/05s. Interestingly, it has the early 
>> version M7261E Control
>> Logic & Microprogram board and the later version M7260 Data Paths board 
>> (with circular baud rate
>> selector switch) as described in:
>>
>> http://gunkies.org/wiki/KD11-B_CPU
>>
>>  From the description there, it seems like an older/newer combination, but 
>> maybe that was common. I
>> would not have guessed that the four possible combinations would all work 
>> together, but maybe
>> they do?
>>
>> I have a couple different drawing sets for the 11/05 and while some have the 
>> matching M7260
>> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
>> schematic:
>>
>> http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
>>
>> The GT40 drawings has the PROM listings and related, so I am hoping that 
>> they match what is in the
>> two boards.
>>
>> Presently, the machine sometimes runs relatively well and other times it 
>> does not. It does have bit
>> 1 stuck ON in memory, but that should be a relatively simple task to 
>> diagnose as it is not
>> intermittent. When the machine is "working" I am able to deposit 0777 at 
>> 0100 and run. When running
>> this simple program, I've experimented with flexing the boards and such, so 
>> it doesn't seem like an
>> obvious poor connection, but that remains to be seen.
>>
>> The machine is a configuration #2 model (as described in the "gunkies" site) 
>> and my initial messing
>> with KM11 boards, reveals that I can step the microcode with a KM11 in 
>> either the #1 or #2 position,
>> but when two KM11s are installed at the same time, they do not function 
>> properly together. Is this
>> expected or do I have an issue there too?
>>
>> Thanks much to those who have provided details and documents on the web, 
>> they have already been of
>> great value and will most certainly continue to be a resource in the future.
>>
>> More updates in the future...
>>
>> --tom
>>
>> On 5/6/16 5:32 PM, Noel Chiappa wrote:
>>>  > From: Mattis Lind
>>>
>>>  > Thanks Noel for sorting this out.
>>>
>>> Eh, de nada. But thank you.
>>>
>>>
>>>  >> I wonder if the ucode in the two versions is identical? The uROM 
>>> chip
>>>  >> numbers should give it, (if they are the same on both versions, 
>>> albeit
>>>  >> in different locations on the board), but I have yet to check. Does
>>>  >> anyone happen to know?
>>>
>>> OK, so the situation here is pretty complicated. To start with / make things
>>> worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of 
>>> PROMs.
>>>
>>> For the data paths board (M7260), both major versions appear to contain the
>>> same PROMs (going by the DEC part numbers), but the chip location (Exx)
>>> numbers are all different.
>>>
>>> For the control board (M7261), the C, E ('early' version) and F ('late'
>>> version) etch revisions each contain mostly the same PROMs, but apparently
>>> with slight differences between the sets of PROMs in each (as reflected in
>>> different DEC part numbers). For details see:
>>>
>>>    http://gunkies.org/wiki/PDP-11/05#Control_PROMs
>>>
>>> to which I have just added all the gory details.
>>>
>>> As to getting the contents of all of them dumped in machine-readable form -
>>> oi vey!
>>>
>>>
>>>  >> on the earlier version (prints for that version are in the GT40 
>>> prints
>>>  >> online
>>>
>>> It turns out that I have hard-copy prints for the "C" etch revision of the
>>> M7261, which do not yet appear to be online; the GT40 prints have the "E"
>>> etch revision.
>>>
>>> I will scan the pages for that revision of the board, and put them up 
>>> 'soon'.
>>> (I'm not doing the whole print set, it's about 1" thick, and most of them 
>>> are
>>> for other things anyway, like MM11-L memory, etc.)
>>>
>>> Noel
>>>
>

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Jay Logue via cctalk]

I also have an 11/05 with the early CPU boards that exhibited stuck bits 
on arrival.  Turned out to be bad transistors in the inhibit circuits on 
the G110.  Pretty easy fix once I tracked it down. So far I've found the 
GT40 print set to be a fairly accurate, at least for the boards I have.


I'll be curious to learn how your serial console works.  Mine had a 
manufacturing defect that had to be corrected before input would work.


--Jay

On 6/13/2021 1:44 PM, Tom Uban via cctalk wrote:

I am working on the first of my two 11/05s. Interestingly, it has the early 
version M7261E Control
Logic & Microprogram board and the later version M7260 Data Paths board (with 
circular baud rate
selector switch) as described in:

http://gunkies.org/wiki/KD11-B_CPU

 From the description there, it seems like an older/newer combination, but 
maybe that was common. I
would not have guessed that the four possible combinations would all work 
together, but maybe they do?

I have a couple different drawing sets for the 11/05 and while some have the 
matching M7260
schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
schematic:

http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf

The GT40 drawings has the PROM listings and related, so I am hoping that they 
match what is in the
two boards.

Presently, the machine sometimes runs relatively well and other times it does 
not. It does have bit
1 stuck ON in memory, but that should be a relatively simple task to diagnose 
as it is not
intermittent. When the machine is "working" I am able to deposit 0777 at 0100 
and run. When running
this simple program, I've experimented with flexing the boards and such, so it 
doesn't seem like an
obvious poor connection, but that remains to be seen.

The machine is a configuration #2 model (as described in the "gunkies" site) 
and my initial messing
with KM11 boards, reveals that I can step the microcode with a KM11 in either 
the #1 or #2 position,
but when two KM11s are installed at the same time, they do not function 
properly together. Is this
expected or do I have an issue there too?

Thanks much to those who have provided details and documents on the web, they 
have already been of
great value and will most certainly continue to be a resource in the future.

More updates in the future...

--tom

On 5/6/16 5:32 PM, Noel Chiappa wrote:

 > From: Mattis Lind

 > Thanks Noel for sorting this out.

Eh, de nada. But thank you.


 >> I wonder if the ucode in the two versions is identical? The uROM chip
 >> numbers should give it, (if they are the same on both versions, albeit
 >> in different locations on the board), but I have yet to check. Does
 >> anyone happen to know?

OK, so the situation here is pretty complicated. To start with / make things
worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of PROMs.

For the data paths board (M7260), both major versions appear to contain the
same PROMs (going by the DEC part numbers), but the chip location (Exx)
numbers are all different.

For the control board (M7261), the C, E ('early' version) and F ('late'
version) etch revisions each contain mostly the same PROMs, but apparently
with slight differences between the sets of PROMs in each (as reflected in
different DEC part numbers). For details see:

   http://gunkies.org/wiki/PDP-11/05#Control_PROMs

to which I have just added all the gory details.

As to getting the contents of all of them dumped in machine-readable form -
oi vey!


 >> on the earlier version (prints for that version are in the GT40 prints
 >> online

It turns out that I have hard-copy prints for the "C" etch revision of the
M7261, which do not yet appear to be online; the GT40 prints have the "E"
etch revision.

I will scan the pages for that revision of the board, and put them up 'soon'.
(I'm not doing the whole print set, it's about 1" thick, and most of them are
for other things anyway, like MM11-L memory, etc.)

Noel

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

Thanks Bill, nice read. Did you get your RK11/RK05 up and running on the 11/05?
My 11/05s both have the low profile side mounted chassis, which I find makes 
them nice and compact,
but limits their expansion without another cabinet.

--tom

On 6/13/21 3:59 PM, Bill Degnan wrote:
> It's no gunkies but I wrote up a few notes about my 11/05 variants and 
> support issues here:
>  https://www.vintagecomputer.net/digital/ 
> .
>
> Bill
>
> On Sun, Jun 13, 2021, 4:44 PM Tom Uban via cctalk  > wrote:
>
> I am working on the first of my two 11/05s. Interestingly, it has the 
> early version M7261E Control
> Logic & Microprogram board and the later version M7260 Data Paths board 
> (with circular baud rate
> selector switch) as described in:
>
> http://gunkies.org/wiki/KD11-B_CPU 
>
> >From the description there, it seems like an older/newer combination, 
> but maybe that was
> common. I
> would not have guessed that the four possible combinations would all work 
> together, but maybe
> they do?
>
> I have a couple different drawing sets for the 11/05 and while some have 
> the matching M7260
> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
> schematic:
>
> 
> http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
> 
> 
>
> The GT40 drawings has the PROM listings and related, so I am hoping that 
> they match what is in the
> two boards.
>
> Presently, the machine sometimes runs relatively well and other times it 
> does not. It does
> have bit
> 1 stuck ON in memory, but that should be a relatively simple task to 
> diagnose as it is not
> intermittent. When the machine is "working" I am able to deposit 0777 at 
> 0100 and run. When
> running
> this simple program, I've experimented with flexing the boards and such, 
> so it doesn't seem
> like an
> obvious poor connection, but that remains to be seen.
>
> The machine is a configuration #2 model (as described in the "gunkies" 
> site) and my initial
> messing
> with KM11 boards, reveals that I can step the microcode with a KM11 in 
> either the #1 or #2
> position,
> but when two KM11s are installed at the same time, they do not function 
> properly together. Is this
> expected or do I have an issue there too?
>
> Thanks much to those who have provided details and documents on the web, 
> they have already been of
> great value and will most certainly continue to be a resource in the 
> future.
>
> More updates in the future...
>
> --tom
>
> On 5/6/16 5:32 PM, Noel Chiappa wrote:
> >     > From: Mattis Lind
> >
> >     > Thanks Noel for sorting this out.
> >
> > Eh, de nada. But thank you.
> >
> >
> >     >> I wonder if the ucode in the two versions is identical? The uROM 
> chip
> >     >> numbers should give it, (if they are the same on both versions, 
> albeit
> >     >> in different locations on the board), but I have yet to check. 
> Does
> >     >> anyone happen to know?
> >
> > OK, so the situation here is pretty complicated. To start with / make 
> things
> > worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of 
> PROMs.
> >
> > For the data paths board (M7260), both major versions appear to contain 
> the
> > same PROMs (going by the DEC part numbers), but the chip location (Exx)
> > numbers are all different.
> >
> > For the control board (M7261), the C, E ('early' version) and F ('late'
> > version) etch revisions each contain mostly the same PROMs, but 
> apparently
> > with slight differences between the sets of PROMs in each (as reflected 
> in
> > different DEC part numbers). For details see:
> >
> >   http://gunkies.org/wiki/PDP-11/05#Control_PROMs
> 
> >
> > to which I have just added all the gory details.
> >
> > As to getting the contents of all of them dumped in machine-readable 
> form -
> > oi vey!
> >
> >
> >     >> on the earlier version (prints for that version are in the GT40 
> prints
> >     >> online
> >
> > It turns out that I have hard-copy prints for the "C" etch revision of 
> the
> > M7261, which do not yet appear to be online; the GT40 prints have the 
> "E"
> > etch revision.
> >
> > I will scan the pages for that revision of the board, and put them up 
> 'soon'.
> > (I'm not doing the whole print set, it's about 1" thick, and most of 
> them are
> > for other things anyway, like MM11-L memory, etc.)
> >
> >       Noel
> >
>

Re: PDP-11/05 (was: PDP-11/05 microcode dump?)

[Bill Degnan via cctalk]

It's no gunkies but I wrote up a few notes about my 11/05 variants and
support issues here:
 https://www.vintagecomputer.net/digital/.

Bill

On Sun, Jun 13, 2021, 4:44 PM Tom Uban via cctalk 
wrote:

> I am working on the first of my two 11/05s. Interestingly, it has the
> early version M7261E Control
> Logic & Microprogram board and the later version M7260 Data Paths board
> (with circular baud rate
> selector switch) as described in:
>
> http://gunkies.org/wiki/KD11-B_CPU
>
> From the description there, it seems like an older/newer combination, but
> maybe that was common. I
> would not have guessed that the four possible combinations would all work
> together, but maybe they do?
>
> I have a couple different drawing sets for the 11/05 and while some have
> the matching M7260
> schematic, only the GT40 drawings (I found on bitsavers) has the M7261E
> schematic:
>
>
> http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf
>
> The GT40 drawings has the PROM listings and related, so I am hoping that
> they match what is in the
> two boards.
>
> Presently, the machine sometimes runs relatively well and other times it
> does not. It does have bit
> 1 stuck ON in memory, but that should be a relatively simple task to
> diagnose as it is not
> intermittent. When the machine is "working" I am able to deposit 0777 at
> 0100 and run. When running
> this simple program, I've experimented with flexing the boards and such,
> so it doesn't seem like an
> obvious poor connection, but that remains to be seen.
>
> The machine is a configuration #2 model (as described in the "gunkies"
> site) and my initial messing
> with KM11 boards, reveals that I can step the microcode with a KM11 in
> either the #1 or #2 position,
> but when two KM11s are installed at the same time, they do not function
> properly together. Is this
> expected or do I have an issue there too?
>
> Thanks much to those who have provided details and documents on the web,
> they have already been of
> great value and will most certainly continue to be a resource in the
> future.
>
> More updates in the future...
>
> --tom
>
> On 5/6/16 5:32 PM, Noel Chiappa wrote:
> > > From: Mattis Lind
> >
> > > Thanks Noel for sorting this out.
> >
> > Eh, de nada. But thank you.
> >
> >
> > >> I wonder if the ucode in the two versions is identical? The uROM
> chip
> > >> numbers should give it, (if they are the same on both versions,
> albeit
> > >> in different locations on the board), but I have yet to check.
> Does
> > >> anyone happen to know?
> >
> > OK, so the situation here is pretty complicated. To start with / make
> things
> > worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of
> PROMs.
> >
> > For the data paths board (M7260), both major versions appear to contain
> the
> > same PROMs (going by the DEC part numbers), but the chip location (Exx)
> > numbers are all different.
> >
> > For the control board (M7261), the C, E ('early' version) and F ('late'
> > version) etch revisions each contain mostly the same PROMs, but
> apparently
> > with slight differences between the sets of PROMs in each (as reflected
> in
> > different DEC part numbers). For details see:
> >
> >   http://gunkies.org/wiki/PDP-11/05#Control_PROMs
> >
> > to which I have just added all the gory details.
> >
> > As to getting the contents of all of them dumped in machine-readable
> form -
> > oi vey!
> >
> >
> > >> on the earlier version (prints for that version are in the GT40
> prints
> > >> online
> >
> > It turns out that I have hard-copy prints for the "C" etch revision of
> the
> > M7261, which do not yet appear to be online; the GT40 prints have the "E"
> > etch revision.
> >
> > I will scan the pages for that revision of the board, and put them up
> 'soon'.
> > (I'm not doing the whole print set, it's about 1" thick, and most of
> them are
> > for other things anyway, like MM11-L memory, etc.)
> >
> >   Noel
> >
>
>

PDP-11/05 (was: PDP-11/05 microcode dump?)

[Tom Uban via cctalk]

I am working on the first of my two 11/05s. Interestingly, it has the early 
version M7261E Control
Logic & Microprogram board and the later version M7260 Data Paths board (with 
circular baud rate
selector switch) as described in:

http://gunkies.org/wiki/KD11-B_CPU

>From the description there, it seems like an older/newer combination, but 
>maybe that was common. I
would not have guessed that the four possible combinations would all work 
together, but maybe they do?

I have a couple different drawing sets for the 11/05 and while some have the 
matching M7260
schematic, only the GT40 drawings (I found on bitsavers) has the M7261E 
schematic:

http://www.bitsavers.org/pdf/dec/graphics/VT11/GT40_Graphic_Terminal_Engineering_Drawings_Feb73.pdf

The GT40 drawings has the PROM listings and related, so I am hoping that they 
match what is in the
two boards.

Presently, the machine sometimes runs relatively well and other times it does 
not. It does have bit
1 stuck ON in memory, but that should be a relatively simple task to diagnose 
as it is not
intermittent. When the machine is "working" I am able to deposit 0777 at 0100 
and run. When running
this simple program, I've experimented with flexing the boards and such, so it 
doesn't seem like an
obvious poor connection, but that remains to be seen.

The machine is a configuration #2 model (as described in the "gunkies" site) 
and my initial messing
with KM11 boards, reveals that I can step the microcode with a KM11 in either 
the #1 or #2 position,
but when two KM11s are installed at the same time, they do not function 
properly together. Is this
expected or do I have an issue there too?

Thanks much to those who have provided details and documents on the web, they 
have already been of
great value and will most certainly continue to be a resource in the future.

More updates in the future...

--tom

On 5/6/16 5:32 PM, Noel Chiappa wrote:
> > From: Mattis Lind
>
> > Thanks Noel for sorting this out.
>
> Eh, de nada. But thank you.
>
>
> >> I wonder if the ucode in the two versions is identical? The uROM chip
> >> numbers should give it, (if they are the same on both versions, albeit
> >> in different locations on the board), but I have yet to check. Does
> >> anyone happen to know?
>
> OK, so the situation here is pretty complicated. To start with / make things
> worse, that CPU uses lots of PROMs. Lots and lots and lots and lots of PROMs.
>
> For the data paths board (M7260), both major versions appear to contain the
> same PROMs (going by the DEC part numbers), but the chip location (Exx)
> numbers are all different.
>
> For the control board (M7261), the C, E ('early' version) and F ('late'
> version) etch revisions each contain mostly the same PROMs, but apparently
> with slight differences between the sets of PROMs in each (as reflected in
> different DEC part numbers). For details see:
>
>   http://gunkies.org/wiki/PDP-11/05#Control_PROMs
>
> to which I have just added all the gory details.
>
> As to getting the contents of all of them dumped in machine-readable form -
> oi vey!
>
>
> >> on the earlier version (prints for that version are in the GT40 prints
> >> online
>
> It turns out that I have hard-copy prints for the "C" etch revision of the
> M7261, which do not yet appear to be online; the GT40 prints have the "E"
> etch revision.
>
> I will scan the pages for that revision of the board, and put them up 'soon'.
> (I'm not doing the whole print set, it's about 1" thick, and most of them are
> for other things anyway, like MM11-L memory, etc.)
>
>   Noel
>