Diablo Series 30 removable disk drives & sector sensor
I've been researching uses of the IBM 2315 disk pack design in various systems. There appear to be two styles of sensors used for sector identification in IBM 2315 disk pack designs. The IBM 2310 disk drive used an optical sensor and notched-ring integrated into the spindle so that a U-shaped assembly of light+sensor is appropriately positioned when the pack is mounted (see: https://www.manualslib.com/products/Ibm-2310-10271354.html ). DEC also used this style in their RK05 drives (see: EK-RK5JF-MM-001_RKO5_RK05J_RK05F_Disk_Drive_Maintenance_Manual_Nov76.pdf, Figure 1-3 and Section 4.2.6 on page 4-16 (56-of-135) "an optical device that contains a light emitting diode and a photosensor". The other style utilizes a magnetic sensor and the hub (perimeter of the flat surface to which the pack is affixed when mounted) itself is notched. A flat sensor including a magnet is suitably positioned with respect to that face when the pack is mounted. HP used this style in their HP7906 drive, which combined a removable disk with a fixed disk (the fixed disk actually provided the sector-timing information for the removeable disk pack; the removeable disk itself only had a single index notch on the hub). I've become confused about the one used with Diablo Series 30 drives, typically employed by OEMs (e.g., Data General). I assume that it was one-or-the-other, but perhaps either might be used based on the requirement of a particular OEM? In D3140-171_Maintanance_Manual_For_Series-30_Disk_Drive_Jan72.pdf, on page 7-17 (92-of-103) Figure 7-9 SECTOR TRANSDUCER ASSEMBLY clearly illustrates the mechanism of a magnetic transducer, although nowhere can I find Series 30 technical documentation that specifically discusses the nature of its sector transducer. All schematics that I have checked do not seem to include any provisions for powering a light source, which is consistent with the use of a magnetic transducer. However https://www.righto.com/2018/03/a-1970s-disk-drive-that-wouldnt-seek.html from Ken Shirriff shows a Diablo drive where Ken clearly (https://lh3.googleusercontent.com/-_meZQXUR5NQ/Wr-34VTNwUI/AAABQe4/fhC1 75xg0Mcm6eeytILHMyUGZ1TFAUzkwCHMYBhgL/w/disk-opened.jpg) illustrates a disk pack that is hard-sectored based on slots-in-ring which AFAIK implies an optical sensor. He references 81503-02_Series_30_Disk_Drive_Maintenance_Nov75.pdf which is non-specific regarding the sector transducer, but on page 5-6 (41-of-63) it refers to there being "two interconnecting wires at the transducer" and Figure 5-7 SECTOR TRANSDUCER ADJUSTMENT appears to me to be consistent with the earlier maintenance manual Figure 7-9 SECTOR TRANSDUCER ASSEMBLY - a magnetic transducer. So is the opened disk pack not actually one for a Diablo Series 30 drive? Or did the Diablo Series 30 include an OEM-specific (?) variant that used an optical sensor? Or perhaps there's something else going on here with the various IBM 2315 disk pack designs regarding sector sensing that I fail to understand? - paul
RE: UNIBUS powoer on/off spec
I like the fact that https://williambader.com/museum/vax/pdphistory.html
shows a cover image plus identifies the marking on the back cover
("EB-17525-20/79 070-14-55").
https://authors.library.caltech.edu/5363/1/MARprocieee06.pdf cites it in the
same manner. Apparently the editors at Proc IEEE thought that was
appropriate :->.
-Original Message-
From: cctalk On Behalf Of Noel Chiappa via
cctalk
Sent: Tuesday, April 5, 2022 5:49 PM
To: cctalk@classiccmp.org
Cc: j...@mercury.lcs.mit.edu
Subject: Re: UNIBUS powoer on/off spec
> From: Paul Koning
> You might give a precise source citation on that page.
Done:
https://gunkies.org/w/index.php?title=UNIBUS_Initialization=6842=
25463=25451
Don't complain to me if the publication data is skimpy; that's all that's in
it! (I mean, we all know that DEC is in Maynard, but the book doesn't say
it...)
Noel
DEC DC319A DLART (DL11 Compatible Asynchronous Receiver-Transmitter)
In case anyone else has been looking some of these, there is a listing for multiple tubes-of-11 on eBay at a moderate price: https://www.ebay.com/itm/123710245814 QTY-11 PCS. AMI SEMICONDUCTOR DC319 C04090 Integrated Circuit - (UIC 40378901) It's documented in the DEC Semiconductor Data Book, Volume 1 (1987), pages 3-27 through 3-41: http://bitsavers.org/pdf/dec/semiconductor/ -
RE: Searching cctalk archives?
In general: http://bitsavers.org/mailing_lists/cctalk_mailing_list/ However I just used Google Search on "PDP-8m Console Switch Problems - fixed! CCTALK CCTECH" and the fourth hit was: http://bitsavers.org/mailing_lists/cctalk_mailing_list/2006-September.txt Then search in that page for "PDP-8m Console Switch Problems - fixed!" --> From ak6dn at mindspring.com Thu Sep 7 02:49:17 2006 From: ak6dn at mindspring.com (Don North) Date: Thu, 07 Sep 2006 00:49:17 -0700 Subject: PDP-8m Console Switch Problems - fixed! -Original Message- From: cctalk On Behalf Of Tom Hunter via cctalk Sent: Tuesday, March 22, 2022 12:24 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Searching cctalk archives? I came across a reference to a cctalk message from 9 September 2006 and would like to read the rest of the thread with the subject "PDP-8m Console Switch Problems - fixed!". Unfortunately it appears that the cctalk archive does not go back to 2006. Is there some place with the complete cctalk archive or at least back to Sept 2006? I have also been trying to search the cctalk archive, but short of downloading every month and unzip it, there appears to be no easy way of searching. What do experienced cctalk members do? Thanks Tom Hunter
RE: Digitronics P135-20 Paper Tape Punch
Yes indeed. No response whatsoever :-<. Not even a receipt acknowledgement.
From: Adrian Stoness
Sent: Friday, March 11, 2022 10:21 AM
To: pbir...@gmail.com; General Discussion: On-Topic Posts
Subject: Re: Digitronics P135-20 Paper Tape Punch
did u try talking to that outfit to see if they got more documents with it?
On Fri, Mar 11, 2022 at 9:08 AM Paul Birkel via cctech mailto:cct...@classiccmp.org> > wrote:
I have the mechanism for a Digitronics P135-20 Paper Tape Punch.
It turns out that Surplus Sales currently has one of these for sale; see
item "(EQP) P135-20/35".
It is accompanied by a three-page snippet of a much longer manual for this
punch.
See: https://www.surplussales.com/equipment/pdf/eqp-p135-20-35.pdf
That's the only documentation that I've been able to find :-{.
I'd very much like to find/acquire the remainder of this manual, or other
relevant documentation. Can anyone help me?
Thank you,
paul
Digitronics P135-20 Paper Tape Punch
I have the mechanism for a Digitronics P135-20 Paper Tape Punch.
It turns out that Surplus Sales currently has one of these for sale; see
item "(EQP) P135-20/35".
It is accompanied by a three-page snippet of a much longer manual for this
punch.
See: https://www.surplussales.com/equipment/pdf/eqp-p135-20-35.pdf
That's the only documentation that I've been able to find :-{.
I'd very much like to find/acquire the remainder of this manual, or other
relevant documentation. Can anyone help me?
Thank you,
paul
Seeking a MC75325L Dual Memory Driver
I have here in my hands a DEC H222A (16Kx18), part of a MM11-DP, that took a blow at sometime in the past. In consequence there are a number of small parts damaged (snapped diode, crushed axial electrolytic, chipped mica capacitor, cracked/broken SIP resister net) but those all appear to be relatively easy to replace. What's not so easy to replace is the MC75325L Dual Memory Driver (L = Ceramic) that was de-lidded in the process :-<. I am wondering whether anyone has one of these ICs in their spare parts drawer that I could acquire? I do see a MC75325P (plastic) on eBay at littlediode_components for ~20USD, plus a surprisingly modest shipping charge (Royal Mail International). UTSOURCE claims to have a supplier of the ceramic part "new", with a significantly higher shipping charge. Before I go with the ceramic part (IMO not the sort of packaging that gets . remarked) I thought that I would check here for alternative sources. Thank you, paul
RE: While on the subject of cabinets...
If it's mounted in a standard BA11-K, no. You should be able to pull it out partially (sufficient to tip up if you have rotating slides) and then there should be locking-buttons on the slides to prevent further extension accidentally. Depressing those buttons will allow you to completely remove the chassis and its attached inner slides; the outer slides will remain in the rack. Be careful with full extraction -- the power supply is heavy and the chassis is unbalanced. It's really a two-person operation, or one best accomplished with some sort of supporting mechanism (even wooden cribbing if you are so inclined). If it's anomalously mounted in a BA11-A (like the 11/44) then there is a finger-tab accessible through the front grill on the upper-right that pulls back a spring-loaded side-tab that engages the rack frame to prevent *any* extension whatsoever. Pull that away from the rack-frame and then pull out the chassis. Of course, it's possible that you simply have rusted slides that are binding, in which case you will simply have to use force. Recommend _pushing_ from the rear if "reasonable yanking" from the front isn't working. Although I've encountered a fair share of rusty slides, all have yielded (slowly) to repeated yanking/pushing, even if only a few centimeters at a time. Penetrating oil applied from the sides will help, but after cleaning and polishing the slides suggest that you use graphite or lithium grease to re-lub when reassembling. Others may have alternative lubrication recommendations. -Original Message- From: cctech On Behalf Of Marc Howard via cctech Sent: Tuesday, March 1, 2022 7:37 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: While on the subject of cabinets... I've got a PDP 11/34 I've never opened up. It's mounted in a H9642 cabinet. I can't get the bloody thing to extend on the chassis track slides. Is there a catch or lock screw on this unit? Thanks, Marc Howard
RE: DEC top-mount corporate cabinet
Your description sounds like the cabinet has already been hacked by a prior
owner to remove a key component. And you're saying that the rear
cross-piece is present but both of the top cross-pieces are absent?
Completely weird. I'll contact you off-list and we can exchange photos to
determine what's-what.
-Original Message-
From: Chris Elmquist
Sent: Tuesday, March 1, 2022 5:21 PM
To: pbir...@gmail.com
Cc: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: Re: DEC top-mount corporate cabinet
Thanks very much Paul and others. The overview you linked is very helpful
as I now have the actual model number for the rack that I have.
It is indeed the H9642-AD 40" "Top Loader" but it is missing whatever cross
piece goes behind the H9544 DA Bezel (#4) shown in the component parts
diagram.
My mystery is what that cross piece behind the bezel looks like, how it
attaches to the vertical rails of the rack on each side and then how the
bezel attaches to the cross piece.
The back of the bezel has a ribbed channel that looks like some kind of
bolts or other threaded or inserted fasteners were screwed or snapped into
this channel and those were attached to the cross piece somehow.
That's my missing link ...
I fabricated an aluminum bar cross piece and then used heavy duty hook and
loop-like fasteners to attach the bezel to this aluminum bar but it's cheesy
and loose. I'd like to someday find the proper solution.
Chris
On Tuesday (03/01/2022 at 03:23AM -0500), pbir...@gmail.com wrote:
> Chris:
>
> The traditional DEC racks/cabinets are either full-height ("standard"
> =
> H960) and part-height ("short" = H967) 19" racks. These are welded
> steel frames built for computer-room type environments. When DEC
> started selling into office environments (think data processing /
> business operations) they designed a new line of cabinetry that was
> intended to fit into an office where sight-lines are important and the
> desire was to look/work more like other types of office equipment.
> The PDP-11/60 was I think an early example of the redesigned cabinets
> -- really a double-wide plus a bit, but of more modest height (roughly
> that of the H967). After that you see single-width cabinets holding
> just 18U like the one that you have -- capable of holding a complete,
> but modest, system. These newer-style cabinets/racks are riveted,
> rather than welded. Emphasis was on style, cost-effectiveness, and RF
shielding given the need to operate near other types of office equipment.
>
> Here's a good overview:
> http://vtda.org/docs/computing/DEC/Catalogs/EA21388-75_CabinetAccessor
> iesSup
> pliesCatalog1981.pdf
>
> On the left side of page 8-of-16 you'll see a description of the 40"
> Medium Systems Series, including diagrams and pictures of the "top-loader"
> (H9642-AD) and "front-loader" (H9642-CA) designs. There isn't any
"mod-kit"
> to go from one to the other. It would be possible to get a functional
> top-loader out of a front-loader with some metal reworking.
> Basically, remove the lid and then (in effect) move the cross-pieces
> down 6U and add what amount to four gusset plates for lateral bracing.
> In the H9642-AD photo you can see the plates on the rear cross-piece.
> The front is similar, but sensitive to ensuring that the center 6U
> isn't significantly occluded; the front cross-piece may require some
> modification. There are a few other changes but moving the
> cross-pieces down are the key. Notice the H9544 CA Trim Kit,
> RL01/RL02 -- these are plastic pieces that bridge the gap between the
> HDD cover and the cabinet side-panels; nice to have but they're mostly
there for style.
>
> If you decide to attempt (or simply want to gauge the complexity of) a
> conversion I can see about getting some close-up photos of the various
> components and connections. A conversion would not be a simple task.
>
> While the brochure speaks of "purchase as component kits" and the
> table simply states "Basic Frame Kit", it's not the *same* frame kit
> for -AD and -CA, and I suspect that "kit" in this case was not an IKEA
> flat-box of parts but rather a factory-assembled frame to which one
> added other components as appropriate for the intended use. These frames
are _seriously_ riveted.
> Notice that H9542-AD is distinct from the H9542-CA "component kit".
>
> (Note that the TU80 -- http://gunkies.org/w/images/5/52/Tu80.jpg -- is
> basically a H9642-AD "top-loader" with a hinged lid and
> special-purpose 13U
> front.)
--
Chris Elmquist
RE: Tandon TM 848-02
Page #14 of: http://www.bitsavers.org/pdf/tandon/TM848-1_TM-848-2_Product_Specification_Mar81.pdf Unless "-02" is different than "-2" ... -Original Message- From: cctalk On Behalf Of Bill Gunshannon via cctalk Sent: Wednesday, February 23, 2022 6:13 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Tandon TM 848-02 Does anyone have anything on the jumper settings for this drive? I would like to jumper it so it can read DEC RX01/RX02 floppies. I am looking at being able to read disks on a non-DEC systems but I would also like to be able to use it on my Andromeda card in a real PDP-11. bill
RE: DEC top-mount corporate cabinet
Chris:
The traditional DEC racks/cabinets are either full-height ("standard" =
H960) and part-height ("short" = H967) 19" racks. These are welded steel
frames built for computer-room type environments. When DEC started selling
into office environments (think data processing / business operations) they
designed a new line of cabinetry that was intended to fit into an office
where sight-lines are important and the desire was to look/work more like
other types of office equipment. The PDP-11/60 was I think an early example
of the redesigned cabinets -- really a double-wide plus a bit, but of more
modest height (roughly that of the H967). After that you see single-width
cabinets holding just 18U like the one that you have -- capable of holding a
complete, but modest, system. These newer-style cabinets/racks are riveted,
rather than welded. Emphasis was on style, cost-effectiveness, and RF
shielding given the need to operate near other types of office equipment.
Here's a good overview:
http://vtda.org/docs/computing/DEC/Catalogs/EA21388-75_CabinetAccessoriesSup
pliesCatalog1981.pdf
On the left side of page 8-of-16 you'll see a description of the 40" Medium
Systems Series, including diagrams and pictures of the "top-loader"
(H9642-AD) and "front-loader" (H9642-CA) designs. There isn't any "mod-kit"
to go from one to the other. It would be possible to get a functional
top-loader out of a front-loader with some metal reworking. Basically,
remove the lid and then (in effect) move the cross-pieces down 6U and add
what amount to four gusset plates for lateral bracing. In the H9642-AD
photo you can see the plates on the rear cross-piece. The front is similar,
but sensitive to ensuring that the center 6U isn't significantly occluded;
the front cross-piece may require some modification. There are a few other
changes but moving the cross-pieces down are the key. Notice the H9544 CA
Trim Kit, RL01/RL02 -- these are plastic pieces that bridge the gap between
the HDD cover and the cabinet side-panels; nice to have but they're mostly
there for style.
If you decide to attempt (or simply want to gauge the complexity of) a
conversion I can see about getting some close-up photos of the various
components and connections. A conversion would not be a simple task.
While the brochure speaks of "purchase as component kits" and the table
simply states "Basic Frame Kit", it's not the *same* frame kit for -AD and
-CA, and I suspect that "kit" in this case was not an IKEA flat-box of parts
but rather a factory-assembled frame to which one added other components as
appropriate for the intended use. These frames are _seriously_ riveted.
Notice that H9542-AD is distinct from the H9542-CA "component kit".
(Note that the TU80 -- http://gunkies.org/w/images/5/52/Tu80.jpg -- is
basically a H9642-AD "top-loader" with a hinged lid and special-purpose 13U
front.)
-Original Message-
From: Chris Elmquist
Sent: Monday, February 28, 2022 2:08 PM
To: pbir...@gmail.com; General Discussion: On-Topic and Off-Topic Posts
Subject: DEC top-mount corporate cabinet
On Saturday (02/26/2022 at 03:21PM -0500), pbirkel--- via cctalk wrote:
> A top-mount corporate cabinet looks like this:
> http://www.cosam.org/images/pdp11-23/front2.jpg The "DECDatasystem"
> front-bar in the photo is over the 1U strengthener that braces the
> upper portion of the rack ... since there is no brace at the top (as yours
has).
> Your cabinet will work fine; in my experience RL02's are always tight
> and fiddly any place but the top-spot.
Is there a (hand-)book that describes the DEC cabinets and in particular
this "top-mount corporate cabinet"? Is there a BA # for this cabinet?
I have an 11/34 in said cabinet but it is missing this 1U strengthener
although I do have the 1U front-bar. I had to jigger a means to hold the
front-bar in place and have been unable to understand how it would correctly
attach to the rack and the strengthener, probably because I don't have the
strengthener!
Any part numbers or drawings that show this arrangement would be quite
helpful.
Thanks!
Chris
--
Chris Elmquist
RE: Racking a PDP-11/24
A top-mount corporate cabinet looks like this: http://www.cosam.org/images/pdp11-23/front2.jpg The "DECDatasystem" front-bar in the photo is over the 1U strengthener that braces the upper portion of the rack ... since there is no brace at the top (as yours has). Your cabinet will work fine; in my experience RL02's are always tight and fiddly any place but the top-spot. The "play" is because those immense-head screws are the pivot-points that allow the chassis to be pivoted up 90 degrees (when the slides are extended) in order to more easily access the underside of the backplane. They are intentionally slightly loose in order for the pivot to work. You really don't need, or want, to play with those screws. -Original Message- From: Rob Jarratt Sent: Saturday, February 26, 2022 3:04 PM To: pbir...@gmail.com; r...@jarratt.me.uk; 'General Discussion: On-Topic and Off-Topic Posts' Subject: RE: Racking a PDP-11/24 Thank you for the reply. > -Original Message- > From: pbir...@gmail.com > Sent: 26 February 2022 08:48 > To: r...@jarratt.me.uk; 'Rob Jarratt' ; 'General > Discussion: On-Topic and Off-Topic Posts' > Subject: RE: Racking a PDP-11/24 > > The conventional mounting for RL02 drives in a corporate cabinet puts > one at > the top with the 6U CPU in the middle *but* that assumes that you have > a corporate cabinet designed for that purpose -- in which case the top > is missing so that the RL02 disk-pack can be directly accessed, and > there is a 1U > divider below the top RL02 that reinforces the rack (and in effect replaces the > 1U lip on your rack top). I saw something somewhere that suggested the RL02 should be at the top with the disk accessible without pulling out the drive. I don't think the cabinet I have was intended to do that, but I will have a closer look. > > AFAIK you should be able to make your rack plan work; it's just the > case that > RL02 are always "top snug" (at least in my experience). Have you > tried raising > the 6U CPU as high as possible *before* tightening the bolts/screws on > the mounting flanges on the slides (to the rack, not to the chassis)? > There's usually ~1/8" of play there. From your photo perhaps you have > already done that as the CPU-front looks to be snug to the rack-top. > If anything it looks as if your RL02 instead need to move down. > I did try raising the CPU as high as possible. Will have another look to see if the RL02s can be dropped a bit lower, but I don't think they can go lower in terms of using lower slots, not unless I want to leave a gap and possible interfere with the space at the bottom where there will be some cables I think. I would like to avoid filing though! > I would start by moving the bottom RL02 down as far as possible, then repeat > with the second RL02. > > Your observation that there is "very little clearance between the CPU > and the > RL02 at the front but more at the back" suggests to me that you need > to fiddle move with the front and /or rear mounting flange positioning > on the various slides. Don't assume that wherever "gravity drops > them" is going to > be correct. > > If none of the suggested adjustments are working then I would consider > getting out a rat-tail file and enlarging the slots on the mounting flanges on > the RL02 slides so as to let them drop a little lower (assuming that > you have > clearance at the bottom!). > > Regardless you shouldn't need to play with the slide-to-chassis > attachment points -- those are always "just so" and not really free to > fiddle with (no > "slop"). There *is* a bit of play in the big black sheet that is screwed onto CPU enclosure. > > In my experience "racking" is a fiddling-time and clearances can be *really* > tight. But ... it can be done :->. Good Luck. > > -Original Message- > From: cctalk On Behalf Of Rob Jarratt > via cctalk > Sent: Saturday, February 26, 2022 3:15 AM > To: General Discussion: On-Topic and Off-Topic Posts > > Subject: Racking a PDP-11/24 > > I am wondering if I have racked my 11/24 correctly. > > As you can see here: > https://robs-old-computers.com/2022/02/10/pdp-11-24-progress/ I have > put the CPU at the top and the two RL02 drives underneath. > > The problem is that the CPU enclosure catches on the RL02 underneath. > There is a bit of play in the mounting bracket: > https://rjarratt.files.wordpress.com/2022/02/cpu-mounting-bracket.jpg. > With a bit of manipulation I can get the CPU to slide in. However, I > am wondering if I have racked it correctly? I don't think there is > room to move > the RL02s down and it would presumably leave a bit of a gap below the CPU. > There seems to be very little clearance between the CPU and the RL02 > at the > front but more at the back, but I am sure that the rails are mounted > horizontally. Is it just a matter of tightening the big screws that > hold the > mounting brackets to stop the play? If so I am not sure I have a big enough >
RE: Racking a PDP-11/24
The conventional mounting for RL02 drives in a corporate cabinet puts one at the top with the 6U CPU in the middle *but* that assumes that you have a corporate cabinet designed for that purpose -- in which case the top is missing so that the RL02 disk-pack can be directly accessed, and there is a 1U divider below the top RL02 that reinforces the rack (and in effect replaces the 1U lip on your rack top). AFAIK you should be able to make your rack plan work; it's just the case that RL02 are always "top snug" (at least in my experience). Have you tried raising the 6U CPU as high as possible *before* tightening the bolts/screws on the mounting flanges on the slides (to the rack, not to the chassis)? There's usually ~1/8" of play there. From your photo perhaps you have already done that as the CPU-front looks to be snug to the rack-top. If anything it looks as if your RL02 instead need to move down. I would start by moving the bottom RL02 down as far as possible, then repeat with the second RL02. Your observation that there is "very little clearance between the CPU and the RL02 at the front but more at the back" suggests to me that you need to fiddle move with the front and /or rear mounting flange positioning on the various slides. Don't assume that wherever "gravity drops them" is going to be correct. If none of the suggested adjustments are working then I would consider getting out a rat-tail file and enlarging the slots on the mounting flanges on the RL02 slides so as to let them drop a little lower (assuming that you have clearance at the bottom!). Regardless you shouldn't need to play with the slide-to-chassis attachment points -- those are always "just so" and not really free to fiddle with (no "slop"). In my experience "racking" is a fiddling-time and clearances can be *really* tight. But ... it can be done :->. Good Luck. -Original Message- From: cctalk On Behalf Of Rob Jarratt via cctalk Sent: Saturday, February 26, 2022 3:15 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Racking a PDP-11/24 I am wondering if I have racked my 11/24 correctly. As you can see here: https://robs-old-computers.com/2022/02/10/pdp-11-24-progress/ I have put the CPU at the top and the two RL02 drives underneath. The problem is that the CPU enclosure catches on the RL02 underneath. There is a bit of play in the mounting bracket: https://rjarratt.files.wordpress.com/2022/02/cpu-mounting-bracket.jpg. With a bit of manipulation I can get the CPU to slide in. However, I am wondering if I have racked it correctly? I don't think there is room to move the RL02s down and it would presumably leave a bit of a gap below the CPU. There seems to be very little clearance between the CPU and the RL02 at the front but more at the back, but I am sure that the rails are mounted horizontally. Is it just a matter of tightening the big screws that hold the mounting brackets to stop the play? If so I am not sure I have a big enough screwdriver! Regards Rob
RE: Is The M9312 Boot Module Essential?
That module was specifically called for in the RH11-AB dual-port Unibus-to-MASSBUS interface as the Unibus B terminator. See RH11-AB_OptionDescr.pdf, Section 4.24 (page 4-32/33), which has a fairly lengthy write-up. -Original Message- From: cctalk On Behalf Of Mattis Lind via cctalk Sent: Friday, February 25, 2022 2:29 AM To: Noel Chiappa ; General Discussion: On-Topic and Off-Topic Posts Subject: Re: Is The M9312 Boot Module Essential? What about the M9300 board? Do you have an idea what the purpose is of that card? It look a bit like a M9302 but with more logic on it and a few jumpers and a LED. It also have a delay line and a monostable flip-flop. Here is a photo of a (dusty) M9300: http://forum.datormuseum.se/data/B21AEA95-02C2-402B-BC97-06790BAEDC88/84B52290-D267-46C8-8B65-1A3EFEF7916B.jpg /Mattis
RE: Is The M9312 Boot Module Essential?
> -Original Message- > From: cctalk On Behalf Of Noel Chiappa via cctalk > Sent: Monday, February 21, 2022 10:19 AM > To: cctalk@classiccmp.org > Cc: j...@mercury.lcs.mit.edu > Subject: Re: Is The M9312 Boot Module Essential? >... > Since the M9302 appears in EK-11034-OP-PRE2, with SACK turnaround, I deduce that the M8264 was > produced _after_ that came out, and post-dates the M9302, to fix the potential CPU hang issue I > described - and was later dropped when the -11/34 switched to the KD11-EA, with that circuit built in. >... > Noel Note that the RICM has an 11/34 configuration that reports a KD11-EA with a M8264 "KD11-D/E". And a M9302 at the bus far-end. See: https://www.ricomputermuseum.org/collections-gallery/equipment/dec-pdp-11-34 _-2 - paul
RE: HP 2100S Power Supply Disassembly Tips
Josh: Did you figure out a safe PS disassembly procedure? If so, what and how did it go? -Original Message- From: cctalk On Behalf Of Josh Dersch via cctalk Sent: Tuesday, February 1, 2022 1:49 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: HP 2100S Power Supply Disassembly Tips Hey all -- I've had this HP 2100S mini sitting on the bench for a bit, waiting, and I wanted to go through the power supply and test/reform the capacitors this past weekend. The processor service docs cover getting the supply out (which is slightly cumbersome) and I have that step done. But neither the processor docs nor the power supply service docs seem to cover how one disassembles the supply itself. (Has a really thorough guide to how the thing works though, that I'm hoping I won't actually have to use anytime soon.) There are a lot of parts in this unit, and I'm not seeing a method to the madness. The capacitors are fairly easy to *get to* but actually removing them for testing / replacement seems to be another matter entirely. Anyone out there done this before and have any advice? Thanks! - Josh
RE: Building a BA08 for a pdp8/L
Thank you. I _would have_ probably also looked at the analogous "MM8I_Schem_Aug69.pdf" print set. But those were antediluvian times; no Bitsavers and DEC wasn't handing out free print sets. You could purchase them, though -- I still have KA10 and MA10 documentation that I acquired that way for my own education/amusement :->. Fortunately I had access to the full (32Kw MC8-I) controller hard-copy documentation for the 8/I courtesy of an amazingly built-out system installation in the lab below us (8/I with a full 32Kw core plus a pair of DF32 plus at least two TU56) who was willing to serve as my personal lending-library :->. AFAICS that documentation hasn't been captured in Bitsavers. I have found my 45 y/o 8x11 taped together photocopies if you decide to go past adding a single additional field. Aside from a few annotations there plus some sketched connector-signal information I haven't found any as-built documentation -- not even a IC-laydown -- although I see that I used SSM MB6A boards for the SRAM arrays. Unfortunately no pictures and the system is (very) long gone. WRT the delay lines, I think that you've nailed it -- my lack of recall is likely because none of the special timing requirements for the RMW cycle(s) for core applied so I didn't need to replicate that part of the control; individual R or W cycles based on the 2102L are necessarily more than fast enough. Unfortunately none of my implementation-related notes/sketches appear to have survived :-<. And the few that do are often on the "clean" side of reused paper. Poor church mice ... I did also find documentation for a MONOSTORE V/PLANAR 1K-word to 8K-word SRAM module (pub. 1976) for an 8/E that I suspect that I studied carefully to see how OMNIBUS-based signaling was being handled in an environment where RMW core was also supported. It claims to have used "AMD DS9408" parts according to the inventory; have never heard of that one. In roughly the same time-period I also built-out an AX08 surrogate that went to Appleton, WI, in support of a newly-minted PhD from our lab. I found some notes relating to the necessary control components plus the use of "brick" type A/D and D/A devices. I suspect that the deal was that the new position came with a PO for an 8/I and BA08A (probably w/o memory), but not an AX08 -- so I was looking for the most cost-effective means to replicate critical AX08 functionality ... and did so. It's been a long time. -Original Message- From: Chris Zach Sent: Saturday, January 22, 2022 7:07 PM To: pbir...@gmail.com; 'General Discussion: On-Topic and Off-Topic Posts' Subject: Re: Building a BA08 for a pdp8/L There's a couple of MC8/L manuals on bitsavers, this might jog your memory. http://bitsavers.informatik.uni-stuttgart.de/pdf/dec/pdp8/pdp8l/ Anyway, the timing seems to be for the read core, transfer into MB, write back into core (because reads are destructive) then send the completed signal. On MOS memory you probably just need to see the state1 line go high (I have something on the address lines) then just put the data into the MB and go straight to signal 4 (since you don't need to rewrite). On a positive note the 8/L will be able to run as fast as it can as it doesn't have to wait for the core memory. Hm. C On 1/22/2022 11:19 AM, pbir...@gmail.com wrote: > I have absolutely no idea! Jameco would have likely been my source for most > components although we did have a Hamilton-Avnet in town and it's possible > that ordered some components from them (I still have a NS databook with their > sticker on it). It's entirely possible that I fiddled with some TTL > gate-delays to derive a good-enough approximation. Where are you getting > your circuit schematic from? Maybe if I look at it a bit something will come > back to mind ...
RE: Building a BA08 for a pdp8/L
I have absolutely no idea! Jameco would have likely been my source for most components although we did have a Hamilton-Avnet in town and it's possible that ordered some components from them (I still have a NS databook with their sticker on it). It's entirely possible that I fiddled with some TTL gate-delays to derive a good-enough approximation. Where are you getting your circuit schematic from? Maybe if I look at it a bit something will come back to mind ... -Original Message- From: cctalk On Behalf Of Chris Zach via cctalk Sent: Friday, January 21, 2022 10:10 PM To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: Re: Building a BA08 for a pdp8/L Hi Paul! That is really interesting. Did you need to recreate the delay lines or any of that circuitry, or was it just wire the NAND gates into the chip address matrix and ignore all the various TP1-TP4 states? Looking at it I could probably build the basic circuitry on a large breadboard, I've certainly got the chips from fixing all those M series boards. That plus a pair of 32k*8 static ram chips from my 386 cache days and I should be set Now where did that big breadboard go? CZ On 1/20/2022 3:51 AM, pbir...@gmail.com wrote: > Not a direct answer Chris, but back in the mid-70's I built a BM8 surrogate > the hard way (we were an impoverished neurophysiology lab so cutting corners > wherever reasonable) using banks of 2102L and S100 RAM PCBs. For density I > piggy-backed the 2102's to get 8Kbyte boards, then 3 boards gave 16Kword, so > 6 RAM boards were sufficient to fill out the memory space. The controller > was a 1:1 implementation of the DEC schematic, which (if memory serves) just > fit onto a single S100 prototyping board. Cabling from the 8/L was simple > ribbon with alternating grounds. Chassis was ad hoc using a S100 backplane > suitably reinterpreted plus a pair of 8" fans. Added suitable additional > DF/IF switches and lamps to the existing filler-panel and then attached that > to the chassis-front so that it all looked pretty good. It worked for many > years without incident, although AFAIK only core memory was used for > execution; the SRAM was used only for data -- and every added word was taken > advantage of :-}. > > So there's an existence proof that what you propose isn't unreasonable. I'd > probably have preferred to have a nice backplane and applicable modules to > WW, but point-to-point wiring on the prototyping board worked. Given my > skill-set at the time it was a rather risky venture, but the ROI was > excellent. Evidently the DEC design was forgiving enough that my recreation > worked on the first try. > > If you decide to pursue the FPGA (or something) approach I'd be interested in > doing the same with my current 8/L. If you go that route, might as well > build out all three bits of DF/IF control even if there may not be any > accompanying front-panel. > > -Original Message- > From: cctalk On Behalf Of Chris Zach > via cctalk > Sent: Wednesday, January 19, 2022 11:08 PM > To: CCTalk mailing list > Subject: Building a BA08 for a pdp8/L > > So now that my pdp8/L is up and running (it now has a serial port and runs > FOCAL69 quite well) I'm thinking about the next step, which is of course more > memory. > > This requires a BA08 or BM8/L or something expansion box but to be > honest I have enough spare flip chips and such from the wrecked 8/I to > build about 3 core memory systems. So given that the schematics for > the > BA08 are online, they look pretty darn simple, I have the parts, and I have > the parts does anyone know if it's possible to get a flip chip backplane to > work on and wire up to emulate a BA08? > > It looks like they just used the data break interface lines to hook up to the > processor. Everything's there, Memory address bus, memory data bus, and the > various signals for jumps and the like that could allow one to decode and > implement the extra instructions needed. > > Hm. Might just be easier to build it with an FPGA or something as it's mostly > linking up simple gates and the whole core memory section could be removed by > a 4k*12 memory array. Anyone ever done this? > > C >
RE: Building a BA08 for a pdp8/L
Not a direct answer Chris, but back in the mid-70's I built a BM8 surrogate the hard way (we were an impoverished neurophysiology lab so cutting corners wherever reasonable) using banks of 2102L and S100 RAM PCBs. For density I piggy-backed the 2102's to get 8Kbyte boards, then 3 boards gave 16Kword, so 6 RAM boards were sufficient to fill out the memory space. The controller was a 1:1 implementation of the DEC schematic, which (if memory serves) just fit onto a single S100 prototyping board. Cabling from the 8/L was simple ribbon with alternating grounds. Chassis was ad hoc using a S100 backplane suitably reinterpreted plus a pair of 8" fans. Added suitable additional DF/IF switches and lamps to the existing filler-panel and then attached that to the chassis-front so that it all looked pretty good. It worked for many years without incident, although AFAIK only core memory was used for execution; the SRAM was used only for data -- and every added word was taken advantage of :-}. So there's an existence proof that what you propose isn't unreasonable. I'd probably have preferred to have a nice backplane and applicable modules to WW, but point-to-point wiring on the prototyping board worked. Given my skill-set at the time it was a rather risky venture, but the ROI was excellent. Evidently the DEC design was forgiving enough that my recreation worked on the first try. If you decide to pursue the FPGA (or something) approach I'd be interested in doing the same with my current 8/L. If you go that route, might as well build out all three bits of DF/IF control even if there may not be any accompanying front-panel. -Original Message- From: cctalk On Behalf Of Chris Zach via cctalk Sent: Wednesday, January 19, 2022 11:08 PM To: CCTalk mailing list Subject: Building a BA08 for a pdp8/L So now that my pdp8/L is up and running (it now has a serial port and runs FOCAL69 quite well) I'm thinking about the next step, which is of course more memory. This requires a BA08 or BM8/L or something expansion box but to be honest I have enough spare flip chips and such from the wrecked 8/I to build about 3 core memory systems. So given that the schematics for the BA08 are online, they look pretty darn simple, I have the parts, and I have the parts does anyone know if it's possible to get a flip chip backplane to work on and wire up to emulate a BA08? It looks like they just used the data break interface lines to hook up to the processor. Everything's there, Memory address bus, memory data bus, and the various signals for jumps and the like that could allow one to decode and implement the extra instructions needed. Hm. Might just be easier to build it with an FPGA or something as it's mostly linking up simple gates and the whole core memory section could be removed by a 4k*12 memory array. Anyone ever done this? C
RE: Mate-n-lok connector for H744 Regulator
See the bottom of: https://gunkies.org/wiki/DEC_standard_modular_regulators I believe that you'll want one or more of these: https://www.connectorpeople.com/Connector/TYCO-AMP-TE_CONNECTIVITY/1/1-48046 0-0 https://www.connectorpeople.com/Connector/TYCO-AMP-TE_CONNECTIVITY/1/1-48045 9-0 Note that both have a minimum order :-<. As for pins: https://www.mouser.com/ProductDetail/TE-Connectivity/60620-1?qs=pn%2Fzyis3Xj HkDeV60Xt%252Btg%3D%3D https://www.mouser.com/ProductDetail/TE-Connectivity-AMP/60619-1?qs=sGAEpiMZ ZMueQxo7L%2FBPyOx7s9t3UY8b -Original Message- From: cctalk On Behalf Of Rob Jarratt via cctalk Sent: Saturday, January 8, 2022 8:27 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Mate-n-lok connector for H744 Regulator To make testing of the H744 a bit easier I would like to try to make up some connectors for the mate-n-lok connector to make it easier to connect power and load. I know the H744 uses a mate-n-lok connector, but there seem to be a lot of different types and I don't seem to be able to find a type that would work. Does anyone know what the correct one is? Thanks Rob
Memory Tech you don't see very often
Selectron Vacuum Tube: https://www.ebay.com/itm/174977901251 Really nice photo-shoot! I wonder what the back-story to this particular tube might be. I don't think that $16.18 shipping would be, um, adequate protection by any measure. Cheap, but not so sure about "cost-effective" . -
RE: PDP-11/44 gas struts
This would be the "11X44" configuration where the 11/44 is mounted in a 40 inch
top-loading H9642 cabinet ("corp cab").
See http://bitsavers.org/pdf/dec/pdp11/1144/1144_UsersGuide.pdf, Figure 4-5
(page 4-7)
-Original Message-
From: cctalk On Behalf Of Zane Healy via cctalk
Sent: Friday, December 24, 2021 3:16 PM
To: jim stephens ; General Discussion: On-Topic and
Off-Topic Posts
Subject: Re: PDP-11/44 gas struts
Out of curiosity, is there a manual for this style PDP-11/44 online? This is
the style I have, but I’m pretty sure my manual is for the pull-out enclosure.
A manual on this enclosure might give some idea on the gas struts.
Zane
> On Dec 24, 2021, at 11:58 AM, jim stephens via cctalk
> wrote:
>
> I have the same system cabinet, but have not looked at it in detail. I think
> from some of the replies, they are thinking about the H960 tall cabinets and
> systems that are pulled out, then rotate on the slides.
>
> This I think is like the hood of a car, then the system tilts up, as the
> cabinet isn't that tall that you can't work on it on top.
>
> As to sources, either automotive sources and match the fit, or a supplier
> like McMaster Carr. I don't think any NOS on these would be any better than
> the ones you have that rotted out.
>
> I only just got the 11/44 and didn't poke at it yet, just moved it from the
> original owner's storage to mine.
>
> I hope it to be one of my first 'big' projects after some PDP8s are tackled.
>
> thanks
> JIm
>
> On 12/23/2021 8:43 PM, Alan Frisbie via cctalk wrote:
>> I have a PDP-11/44 system in the DEC 41" high cabinet.
>> It is designed to be tilted up for service, aided and supported by
>> two gas struts, one on each side.
>>
>> Unfortunately, after all these years, the struts have failed and do
>> not provide any assistance. That box is heavy!
>>
>> Does anyone know where I can get replacement gas struts?
>>
>> Thanks,
>> Alan Frisbie
>>
>
RE: PDP-11/70 Boards
Seems to me that the actual coil resistance will limit the max-current at lower voltages. 20 A through wire sized for 1 A seems ... unlikely? -Original Message- From: cctalk On Behalf Of Mike Katz via cctalk Sent: Wednesday, December 8, 2021 5:58 PM To: General Discussion: On-Topic and Off-Topic Posts ; wrco...@wrcooke.net Subject: Re: PDP-11/70 Boards More accurately up to it's rated wattage "Power = Voltage * Current" after all. If you have a 100W max variac you can draw 20A @ 5V (approx) but only 1A at 100V. On 12/8/2021 4:44 PM, Mike Katz via cctalk wrote: > "As a general rule, a variable transformer (Variac) can provide full > rated current at any output voltage. So a 2.5A unit can provide 2.5 A > at 1V, 10V, 120V, etc. With a 20V output, that is 50 VA (Watts, sort > of)." > > Up to the current rating of the variac. When you draw more current > than the transformer can deliver then the voltage will sag. > > On 12/8/2021 4:22 PM, Will Cooke via cctalk wrote: >> >>> On 12/08/2021 3:58 PM Rob Jarratt via cctalk >>> wrote: >>> So, to supply the bricks on the bench, would a variac rated at 2.5A >>> be OK? I am not sure I know how much current the bricks will draw at >>> 20VAC, and at what voltage the 2.5A rating is given. Otherwise, >>> would this do the trick? >>> https://cpc.farnell.com/block/steu250-48/transformer-250va-230-400v- >>> 2-x/dp/TF01418?st=24v%20transformer >>> >>> Thanks >>> >>> Rob >>> >>> > JRJ >> As a general rule, a variable transformer (Variac) can provide full >> rated current at any output voltage. So a 2.5A unit can provide 2.5 >> A at 1V, 10V, 120V, etc. With a 20V output, that is 50 VA (Watts, >> sort of). >> >> Will >> >> "I was born not knowing and have had only a little time to change >> that here and there." >> Richard Feynman >
RE: Need picture of power supply mounted in 11/40 cabinet
Marc: Do you have the 11/40-specific wiring harness? Assuming that you do it's a bit tricky -- not so much mounting a given supply (aside from the fact that they are heavy and awkward to work with even when minimally populated), but because there is a very tight tolerance between them to thread the wiring harness. I've determined the hard way that you really need to install the lower one first, then the harness, then the upper one. At least for me it wasn't practical/possible to install the harness after-the-fact. There's also a bit of work involved in threading both of the AC power cables plus the pair of power-control cables (assuming that you're using a DEC power controller) via the right-side vertical rack channel -- which also interact with the power harness placement. Once everything is cabled-in-place the result is maximally compact, but getting there is not simple. Yes, the power cable wiring isn't well-described anywhere IMO. You have to stare at the puzzle-pieces for a while and "dry fit". Harness shape/stiffness helps eyeball how to fit the pieces together, but the importance of the rack vertical side-channel in making everything fit is not, IMO, made at all clear anywhere in the various documentation -- although it can be inferred from careful examination of a few graphics in various documents. The 11/40, the 11/45-50-55, and the 11/70 share the same design in this respect so documentation for one will serve you well in any of these cases. If you can tackle the task *before* installing the BA11 chassis you'll find it easier. If you're not using a standard DEC rack or don't have an equivalent vertical side-channel to work with then IMO you'll need to get very creative ... and the 11/40-specifics wiring harness may not work at all and you'll need to build your own. Fortunately I didn't need to explore that path ... Good luck! -Original Message- From: cctech On Behalf Of Marc Howard via cctech Sent: Saturday, December 4, 2021 10:28 PM To: General Discussion: On-Topic Posts Only Subject: Need picture of power supply mounted in 11/40 cabinet Hi, I've got an 11/40 I'm going to start working on. Problem is that there are two power supplies (H742 and H7420) that came with it but neither was mounted in the rack. Could someone post/send/etc. photos of how the power supply mounts in the rack? Also how is the power cabling routed (I think I'm missing this part)? Thanks, Marc Howard
RE: Unrecognized DEC Power Supply in PDP-11/44 Configuration
Josh & Pete: Thank you for the identification. Don't think that the unidentified quad-boards constitute a SMD controller. I guess the SMD controller was in the second chassis and went wherever the HDD went. Strange that the PS didn't go with it. I can feel a bit better for not having recognized the PS :-}. Rick: The UDA50 is cabled up the rear of the rack to a connector-plate near the top of the rear-rails. No photo of the plate present, but the cabling is clear on the side-photo of the rack. So presumably there was a second rack in the original configuration ... probably also housing a vertical-mount 9" tape drive. -Original Message- From: cctalk On Behalf Of Pete Turnbull via cctalk Sent: Friday, December 3, 2021 9:30 AM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: Unrecognized DEC Power Supply in PDP-11/44 Configuration On 02/12/2021 16:37, Josh Dersch via cctalk wrote: > On Thu, Dec 2, 2021 at 6:29 AM pbirkel--- via cctalk > > wrote: > >> Does anyone recognize the (presumably) DEC power supply on the front >> half of the rack-bottom in the 11/44 listing at: > It's not a DEC power supply, it's a Fujitsu power supply, likely for > an > M2284 SMD drive. Probably went in the empty slot you mention below. Yep. Looks identical to the Fujitsu PSU in my 11/40 rack, and the rails are the same as my Fujitsu rails. -- Pete Pete Turnbull
Unrecognized DEC Power Supply in PDP-11/44 Configuration
Does anyone recognize the (presumably) DEC power supply on the front half of the rack-bottom in the 11/44 listing at: https://www.ebay.com/itm/363640137050 Blurry photo, but it looks like there are a 4x3, a 3x3, and a 3x5 Molex connector, and two brown mini-modules protruding from the right side. If so, then what purpose did it likely serve? It appears that the 6U immediately below the 11/44 was likely occupied by an RX02 given the presence of an M8256 in the 11/44 backplane (and skinny mounting rails, although I thought those were usually at the bottom of the RX02), and that included its own power supply (which wasn't very beefy either, nor did it need to be). What went into the 6U immediately above the power supply is unclear; there is a HEX Wespercorp TC130 Tape Controller as well as three unknown QUAD modules in the 11/44 backplane. Perhaps there was a horizontal autoload tape drive mounted there that required a separate power supply? Curious! paul
