[cctalk] VCF and System Source Computer Museum swap meet this weekend

[Mark G Thomas via cctalk]

Hi,

I am curious if anyone here might be planning on attending.

https://museum.syssrc.com/artifact/events/3000/

The Vintage Computer Federation and the System Source Computer Museum are 
hosting a vintage computer repair workshop on Saturday July 22nd and 
Sunday July 23rd 2023
...

Mark

-- 
Mark G. Thomas , KC3DRE

Re: Xerox 820/II 8/16 Prom/Eproms ( Masters ) on e-bay

[Mark G Thomas via cctalk]

Tom,

On Wed, Aug 11, 2021 at 11:05:59AM -0500, Tom Uban wrote:
> Ok, I was going by the appearance of my case being the older style. I had not 
> considered the number
> of PROMs, but now that you mention it, my old Ferguson Big Board (which was 
> an 820 clone) only had
> two PROMs.

If you still have any 8" floppies from your Big Board, these will probably 
boot and work in the 820 as well as 820-II.

...
> >> At some point, I need to ask someone to make me bootable 8" floppies, but 
> >> I suppose I need to
> >> determine if it is 820 or 820-II first...
> > I can able to help you with floppies. The floppies are standard 
> > IBM 3740 Single Density and easy to write with Imagedisk software 
> > and a PC-connected 8" drive.
> What do you use to connect an 8" drive to a PC?

This adapter is useful: http://www.dbit.com/fdadap.html

But, if your floppy doesn't require a TG43 signal, you could just
wire a custom cable with no logic needed, or get something like this 
on e-bay: https://www.ebay.com/itm/114924378003

Additionally, some PC floppy controllers do not work for some kinds
of floppy encodings. Here is the article I used as a guide. I've been
using an Adaptec AHA-1522A SCSI+Floppy interace, which has a good 
FDC chip for optimum floppy format support.

  https://retrocmp.de/fdd/general/disk-imaging.pdf

> > Both the swithing supply in my 820-II and it's external 8" drive box 
> > had failed. I replaced the supply in the 820-II case with a modern 
> > switching supply that easily fit. The HV bleeder resister for my CRT 
> > was arcing, so I replaced that. I replaced all the electrolytics on 
> > the monitor board. I also replaced the sockets for my ROMs, as some 
> > of their contacts "sprung" when I replaced the chips, but I do not 
> > recommend doing this unless it is absolutely necessary and you have 
> > good tools and practice.
> I had not turned on my box for a number of years, but when you posted, I 
> decided to try it and it
> worked perfectly, which I suppose is just lucky. I do have the tools and 
> skills to work on it if it
> were to fail, but won't likely make changes unless it does.

I'm all for not fixing it if it's not broken. But, I do suggest careful 
inspection of the electrolytics on the motherboard and monitor, especially 
since the monitor board is right above the logic board, so if a cap 
phsically leaked, the corrosive stuff that comes out could drip onto the 
logic board. I see this mostly in SMD style electrolytics, but have seen 
those like the ones in my 820-II physically leak, and the damage can be 
serious.

> > The 820-II restoration was a fun and rewarding project. It is well 
> > documented, easy to work on. It was also my first ever CP/M computer. 
> > When I was in high school, the 820 motherboards were readily available 
> > for $75.
> >
> > Mark
> It sounds like you had a good time, which in my opinion is the main goal!
> 
> --tom

-- 
Mark G. Thomas , KC3DRE

Re: Xerox 820/II 8/16 Prom/Eproms ( Masters ) on e-bay

[Mark G Thomas via cctalk]

Hi Tom,

On Wed, Aug 11, 2021 at 09:37:24AM -0500, Tom Uban wrote:
> I have a Xerox 820. I don't know how to tell if it is a -II or not. It is 
> marked as U05-013264 September 1984.

You have an 820-II; the original 820 only has two ROMs (U63, U64).

> It powers on and boots the monitor. Looking at the PROMs, they are labeled:
> U33 5.0, U34 5.0, U35 5.0, U36 5.0, U37 4.01, U38 4.01
...
> At least some of the ROMs appear to be available here (along with other info):
> 
> http://bitsavers.org/pdf/xerox/820-II/firmware/

I must have worked on mine right before someone put those files on bitsavers.

I vaguely remember some alternate ROM version that supported a newer style 
keyboard, and was incompatible with my older setup, but I do not remember 
specifics. Labels in the e-bay photos also support that.

> At some point, I need to ask someone to make me bootable 8" floppies, but I 
> suppose I need to
> determine if it is 820 or 820-II first...

I can able to help you with floppies. The floppies are standard 
IBM 3740 Single Density and easy to write with Imagedisk software 
and a PC-connected 8" drive.

My 820-II currently boots and runs from disk images on SD cards, via 
a Lotharek HXC floppy emulator, with appropriate cable wiring. I used 
images found on the internet, and some I created from very old floppies 
of mine using Imagedisk on a PC with an 8" floppy connected. I highly 
recommend the Lotharek HXC floppy emulators. My only wish is the 
display on the floppy-form-factor version were easier to read.

Both the swithing supply in my 820-II and it's external 8" drive box 
had failed. I replaced the supply in the 820-II case with a modern 
switching supply that easily fit. The HV bleeder resister for my CRT 
was arcing, so I replaced that. I replaced all the electrolytics on 
the monitor board. I also replaced the sockets for my ROMs, as some 
of their contacts "sprung" when I replaced the chips, but I do not 
recommend doing this unless it is absolutely necessary and you have 
good tools and practice.

The 820-II restoration was a fun and rewarding project. It is well 
documented, easy to work on. It was also my first ever CP/M computer. 
When I was in high school, the 820 motherboards were readily available 
for $75.

Mark

-- 
Mark G. Thomas , KC3DRE

Xerox 820/II 8/16 Prom/Eproms ( Masters ) on e-bay

[Mark G Thomas via cctalk]

Hi,

I'm not prepared to lay out $200 for these Xerox ROMs, but if I do manage 
to get them, I'll read and share them. I did not know there were 5.0 ROMs 
for the 820-II, but it appears there were, and they are included.

https://www.ebay.com/itm/184980603844

Mark

-- 
Mark G. Thomas , KC3DRE

Xerox 820/II 8/16 Prom/Eproms ( Masters ) on e-bay

[Mark G Thomas via cctalk]

Hi,

I'm not prepared to lay out $200 for these Xerox ROMs, but if I do manage
to get them, I'll read and share them. I did not know there were 5.0 ROMs
for the 820-II, but it appears there were, and they are included.

https://www.ebay.com/itm/184980603844

Mark

-- 
Mark G. Thomas , KC3DRE

Re: XXDP diagnostic sources

[Mark G Thomas via cctalk]

Hi,

On Mon, Mar 29, 2021 at 08:02:28AM -0700, Robert Armstrong via cctalk wrote:
>   Hopefully this is an easy question - are the sources for the XXDP
> diagnostics online anywhere?  I particularly looking for NKXA, the
> Falcon-11/KXT11/DCT11 one.  

Not sure if it helps any, but this was recently posted:

Newsgroups: alt.sys.pdp11
Subject: XXDP+ recovered source
From: Ian Hammond 

I've finally completed reverse-assembling the full source code of the XXDP+ 
monitor (HMDLD0) and uploaded it to github, along with transcriptions of the 
XXDP+ File Structure specification and the XXDP V2 Driver Guide (minus the 
appendices), along with originals of some related documents.

https://github.com/rust11/xxdp/tree/main

-- 
Mark G. Thomas , KC3DRE

Re: Digitalker 54104 IC

[Mark G Thomas via cctalk]

Hi,

On 2/13/21 9:15 AM, Bill Gunshannon via cctalk wrote:

On 2/12/21 6:09 PM, Ethan Dicks via cctalk wrote:

On Fri, Feb 12, 2021 at 6:01 PM Jim Brain via cctalk
 wrote:

But, I'm sad because no one either has one nor can help me test this
one.  So, I cannot enjoy the thrill of making it say inappropriate 
stuff :-(


I have several vintage speech ICs, but not that one.



I do as well.  I have the Radio Shack "Voice Synthesizer IC Set"
sitting on the desk in front of me right now.

bill



BG Micro sold a board called I believe the CompuTalker, with the 
SP0256A-AL2 and CTS256AL2/P pair, like the ICs Radio Shack sold. I have 
one of these boards sitting in front of me that I recently mounted in a 
nice case with power supply. Mine had some leaky electrolytic caps, but 
fortunately the damage was minimal and easily fixed.


I found reference to it in this posting here: 
https://groups.google.com/u/1/g/comp.sys.tandy/c/X_6fSse6As4


I've temporarily (please  save these if you want them) copied what I 
could find in terms of documentation and schematics for these ICs here:


http://files.markgthomas.com/dl/SP0256-speech-IC-board/

Photos of mine are included.

Mark

--
Mark G Thomas , KC3DRE

Re: P112

[Mark G Thomas via cctalk]

Hi Bill,

On Wed, Dec 04, 2019 at 01:06:39AM +, Bill Gunshannon via cctalk wrote:
> On 12/3/19 7:51 PM, Craig Ruff via cctech wrote:
> > Just in case someone else hasn't already responded, the P112 does not use 
> > DOS style fdisk partitioning for a hard disk. It is done in the BIOS image, 
> > and then the logical disks have to be initialized. This is described in the 
> > "P112 GIDE Construction.pdf" document.
> > 
> > I've only used 3.5" floppies, which work fine. You can also attach a PATA 
> > CD-ROM drive and access disks with a program that escapes my memory at the 
> > moment.
> > 
> 
> Along this line I have solved one problem.  I mentioned INIT in
> RSX180 printing gibberish on the screen when trying to init a
> hard disk partition where it had worked on a floppy.  Problem
> was the size of the partitions.  I had tried just making one
> partition for the test I learned that FDISK will make partitions
> too big for any of the P112 OSes.  I now have a hard disk with
> 5 partitions to play with.  On to the  next problem.
> 
> bill

I have a pair of P112 systems, both with GIDE interfaces, booting CP/M from 
CF cards successfully. I have not done anything with RSX180 though.

I have been meaning to try and get one reading/writing 8", ideally 3270 
format, CP/M floppies, but have not gotten around to working on this yet, 
and have no idea how easy or difficult that might be.

When I put these together and was getting them working initially, Terry 
Gulczynski was very helpful. See his site at http://www.stack180.com/ 
You may want to get the latest P112 ROM image and corresponding CF card 
image from his site.

Mark

-- 
Mark G. Thomas , KC3DRE

Re: P118

[Mark G Thomas via cctalk]

Hi Bill,

On Fri, Nov 29, 2019 at 02:29:45PM +, Bill Gunshannon via cctalk wrote:
> 
> It's not really classic (although it does try to pretend to be :-)
> but does anyone here do anything with the P118 SBC?  I am trying to
> get 8" disks running on it but I am seeing some rather strange behavior.

Do you mean the p112?

Mark

-- 
Mark G. Thomas , KC3DRE

Re: 11/93 Rebuild

[Mark G Thomas via cctalk]

Rod, others,

I have so far been unsuccessful getting my CQD220A for SCSI HD, and RQDX3 for 
floppy to coexist in an 11/83, at least with bsd2.11.  I am eager to hear 
whether you get both controllers working in the same box, and how.

Mark

Mark G. Thomas (m...@misty.com), KC3DRE

> On May 18, 2019, at 15:10, Rod Smallwood via cctalk  
> wrote:
> 
> Hi Guys
> 
>Well the RD53 in my 11/93 finally clapped out.
> 
>The CPU is a late model KDJ11-E with everything on the one board.
> 
>So its a switch from MFM to SCSI Drives.
> 
>A CQD220A will drive the hard disk and the RQDX3 will stay to look 
> after the RX50
> 
>I've  put the Hard Drive on the primary CSR address (17772150) and I 
> will shift the RQDX3 to an alternate CSR
> 
>Comments as to if this is the right way round and what CSR's to use 
> for the two controllers invited.
> 
>   Rod
> 
> 
> -- 
> 
> 

Re: 2.11 BSD on an 11/93 with an CMD SCSI Module

[Mark G Thomas via cctalk]

Hi Bill,

On Fri, Mar 15, 2019 at 08:55:05PM +, Bill Gunshannon via cctalk wrote:
> 
> Can I assume that all the patches have been applied and tested and
> none of them have been rescinded?
> 
> Next, can I assume one need only apply them all in order to bring a
> system up to current level?
> 
> And then the logical direction this is going.  Is there any where I
> can find a file containing all of the patches already unpacked so I
> can feed them all into a system just installed?  Dealing with them
> in the only format I have found so far could take weeks to actually
> run them.  :-)

I've been using Compact Flash cards in CF-SCSI adapters with my 11/83s,
with CMD SCSI controllers like yours. The beauty of these CF cards is I 
can back them up and copy them via my Mac and Linux systems so easily.

If you get one of these Aztec Monster CF-SCSI adapters, I could send
you an installed, bootable, patched BSD2.11 Complact FLash card, or 
image file you could put on a CF or disk. I'll follow up with you off 
list. Or, maybe there is some way you could write one of these images 
out to a SCSI disk via another system.

I'll follow up with you off-list.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: WTB: Data I/O 351A-070, 071, 072 Socket Adapters

[Mark G Thomas via cctalk]

Hi,

> On Jul 27, 2018, at 18:08, systems_glitch via cctalk  
> wrote:
> 
> All,
> 
> I'm looking for any or all of the following Data I/O Socket Adapters:
> 
> 351A-070 (8741, 8748, etc)
> 351A-071 (8751)
> 351A-072 (8755A)

I suggest asking on the DATAIOeprom list on groups.io too.

I’m looking for a Unipak-2b.

Mark Thomas

Re: old DEC stuff

[Mark G Thomas via cctalk]

Hi,

On Wed, May 30, 2018 at 11:52:13AM -0500, Jay West via cctalk wrote:
> Dominique wrote:
> $75 for one toggle switch ? $9,999.00 for a rusty PDP8L ?
> 
> hem ... No
> -
> Mitch Miller is a really good guy, and very "collector friendly".
> He still sells to a lot of business clients, and those are the prices he can 
> get for those in that market.
> 
> However, if you call or email him - let him know you are a collector - you'll 
> find him willing to work with you.

My experience has been as Jay suggests. Mitch has been both extremely 
helpful, and reasonable to work with as a hobbyist on a budget, you just 
need to make clear up front you are a hobbyist; maybe mention CCTALK.

I visited his warehouse on my Dayton Hamvention trip last week, and came
away with some considerably better deals from Mitch than from the hamfest 
fleamarket. I know Mitch is interested in doing more hobbyist business,
and understands dollar amounts and expectations are different than when
selling to a government agency or big business.

I see rusty PDP8s on e-pay from various sellers for what seem to me like 
crazy amounts, though am not sure if they actually sell for that kind of 
money. Maybe there is another entire category of collector who buys that 
kind of stuff for that kind of money.

It would have been my loss had I written off Mitch on the basis of some 
of Mitch's listings expensive, but admittedly rare, pdp-11 switch listings.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: P112

[Mark G Thomas via cctalk]

Hi Bill,

On Sun, Apr 08, 2018 at 12:36:35AM +, Bill Gunshannon via cctalk wrote:
> 
> It's not really Classic Hardware, but it does run some pretty classic
> OSes.  Anybody here working with the P112?  I have had a couple for
> ages but never had time to play with them.  I see them now as a
> possible way to manipulate floppies (including 8") from classic systems
> so I decided to give it a try.  Problem is, it won't boot anything.  Not the
> disk that came with it and none of the images I got off the web.
> Anybody here know anything about them?

I see you have made progress since this post, but I wanted to chime 
in. I have two, with GIDE cards, and booting from CF cards. One has the
LAN interface card (see http://stack180.com/). I haven't been using 
the floppies, though have always meant to try to get it to do SSSD 
8" format for compatibility with tons of CP/M floppies I have.

I was always surprised not to hear more from other p112 users.

There is a mailing list, but the last post I know of was five years 
ago when I asked if anyone else was on the list.

http://lists.feedle.net/cgi-bin/mailman/listinfo/p112

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

[RESOLVED] Re: EPROM baking

[Mark G Thomas via cctalk]

Hi,

Please see resolution below, if you are curious about how this turned out.

On Wed, Dec 20, 2017 at 09:18:50PM -0500, Mark G Thomas via cctalk wrote:
> Hi,
> 
> > On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
> > cctalk@classiccmp.org> wrote:
> > 
> > > Hi,
> > >
> > > I am working on several projects requiring 2708 and 2716 EPROMs, and
> > > am finding some of my chips will not erase, and some will not take
> > > a program. I've also learned more in the past week than I wanted
> > > to know about repairing Data-I/O 29a/b programmers.
> > >
> > > I vaguely remember in the 1990s baking such EPROMs in the oven, but
> > > I do not remember temperature or time. I was surprised that Google
> > > didn't turn up anything useful with this info.
> > >
> > > I'm sure someone here will have some notes on EPROM baking.
> > >
> > > Mark
> > 
> > Mark,
> > 
> > If this is an issue about reviving bad eproms?  I assume you have tried the
> > regular stuff.
> > 
> > What process are you using now to erase 2708/16's?  I have a simple eraser
> > unit and it seems to always work.  Some eproms go bad but I never have
> > issues with erasing them.  My point is that maybe you need a better prom
> > eraser unit.  
> 
> They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)
> 
> > I would avoid baking them until you have exhausted other
> > options.  Not sure what others think.  This topic has come up before here,
> > about putting them outside and all that.  The erasers are all over ebay,
> > and the hardware store is full of the correct types of lighting, why not
> > make a box that will do the job?I assume there is more to it that
> > simply erasing them.
> > 
> > 
> > Bill

After more experimentation I came to the following conclusions.

1) Some of my chips are legitimately bad, erasing fine but won't take a program.

2) Many of the chips were failing to program because my Batronix 
   programmer apparently requires more current than my USB port provides. 
   This surprised me because I have been programming chips for years 
   using this programmer on this computer port successfully, and this 
   is the first I have had the problem. Using a Anker powered USB hub solved
   things. My Batronix programmer even arrived with a cheap powered hub 
   when I ordered it, but I never used it because it was shipped with an 
   incompatible wall wart, but looking at it in the box gave me the idea
   that this might be the issue.

3) I thought I had ruled out the programmer (#2) because of troubles 
   programming those same chips using another programmer, but I probably 
   had the wrong chip type selected, or simply failed on some of the #1 
   chips so assumed that was my only problem.

Mark


-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: wonky eproms

[Mark G Thomas via cctalk]

David,

This might seem stupid, but I recently had peculiar results with a usb-powered 
programmer failing on certain ranges of addresses on certain chips, that turned 
out to be inadequate current available on my USB port. For me, a high-current 
powered USB hub solved it. I programmed a huge number of chips successfully 
before I ran into this problem with a particular batch of chips.

Mark

Mark G Thomas

> On Feb 4, 2018, at 9:40 AM, David Griffith via cctalk  
> wrote:
> 
> 
> I have a few tubes of ST-branded M27C256B UV-erasable EPROM chips.  All of 
> these fail to program starting at 0x200 until 0x27F.  At 0x200, 0x00 is 
> written, then until 0x27F, the bytes are 0xFF.  What would cause this? Can it 
> be fixed by an extra-long time in the eraser?  Should I just break out the 
> hammer?
> 
> At least I know the programmer is capable of programming a TI-branded 27c256 
> and 29c256 flash chips.  Might there be a bug in the programming software?
> 
> FWIW, I'm using a Minipro TL855.  Linux software is available at Github: 
> https://github.com/vdudouyt/minipro
> 
> -- 
> David Griffith
> d...@661.org
> 
> A: Because it fouls the order in which people normally read text.
> Q: Why is top-posting such a bad thing?
> A: Top-posting.
> Q: What is the most annoying thing in e-mail?

Re: Adaptec 1522A SCSI Support (was re: New TestFDC Results Registry)

[Mark G Thomas via cctalk]

Hi,

On Thu, Jan 18, 2018 at 08:26:45PM -0600, Jason T via cctalk wrote:
> On Thu, Jan 18, 2018 at 7:55 PM, Richard Cini  wrote:
> > I use this card as a floppy/disk controller in a PC/AT that's used solely 
> > for imaging. The controller is connected to two Seagate ST-2502N (442MB) 
> > hard drives running MS-DOS 6.22. Works like a champ. Cables are readily 
> > available on eBay but since they're regular 50-pin IDC connectors, you can 
> > DIY if needed -- connectors are readily available.
> 
> Do you have (and can you post) the MS-DOS drivers for that card?  I
> also run one in my floppy imager machine, which dual-boots btw. MS-DOS
> and some later Linux.  Having SCSI for at least one of the OSes would
> be nice.
> 
> I could also switch the other partition over to FreeBSD, as Warner L 
> suggested.

I think you want this:  http://files.markgthomas.com/dl/adaptec/EZSCSI40.IMD
(This URL is temporary.)

I just found, imaged, and installed it, on my disk-imaging PC using
an AHA-1522A:

---
IMD 1.18: 24/12/2017  4:54:15
Adaptec EZ-SCSI v4.01a Setup Diskette Disk 1of1 HD 3.5
Windows 95/NT/3.1x and DOS Drivers
>From Windows 95 or NT Click Start, Run, Type a:\setup
>From Windows 3.1 or NT 3.52 File/Run Type a:\setup
>From DOS Type a:, Type dosinst
---

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: Google, Wikipedia directly on ASCII terminal?

[Mark G Thomas via cctalk]

Hi,

On Tue, Jan 16, 2018 at 02:07:59PM -0700, Grant Taylor via cctalk wrote:
> On 01/16/2018 12:18 PM, Anders Nelson via cctalk wrote:
> >I suppose one could emulate the telephone carrier dial tone and
> >ring back tone with a third device, then the modems would just act
> >like a direct connection after their handshake?
> 
> I doubt that will work quite like you are thinking.  There is more
> to an analog phone line than the audio that comes over it.  Namely
> the loop current and voltage are also additional bits of signaling.
> 
> I don't think there is such a thing as a cross over phone line.
> 
> You will quite likely need something like an old school PBX that
> provides analog ports to pull this off.

Teltone and several other companies made/make phone line similators
which provide battery, dial tone, ringing, caller ID (sometimes), DTMF 
(and maybe even pulse?) dialing between several ports. These are designed 
for testing and demonstrating fax machines, modems, and other analog 
phone gear.  I'm not talking about the sophisticated bench testing gear 
simulators which provide simulated line loss, delays, and noise, but 
the simple small portable 2-8 line devices. A quick search on e-bay 
produces lots of listings for these devices.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: EPROM baking

[Mark G Thomas via cctalk]

Hi,

> On Wed, Dec 13, 2017 at 9:08 AM, Mark G Thomas via cctalk <
> cctalk@classiccmp.org> wrote:
> 
> > Hi,
> >
> > I am working on several projects requiring 2708 and 2716 EPROMs, and
> > am finding some of my chips will not erase, and some will not take
> > a program. I've also learned more in the past week than I wanted
> > to know about repairing Data-I/O 29a/b programmers.
> >
> > I vaguely remember in the 1990s baking such EPROMs in the oven, but
> > I do not remember temperature or time. I was surprised that Google
> > didn't turn up anything useful with this info.
> >
> > I'm sure someone here will have some notes on EPROM baking.
> >
> > Mark
> 
> Mark,
> 
> If this is an issue about reviving bad eproms?  I assume you have tried the
> regular stuff.
> 
> What process are you using now to erase 2708/16's?  I have a simple eraser
> unit and it seems to always work.  Some eproms go bad but I never have
> issues with erasing them.  My point is that maybe you need a better prom
> eraser unit.  

They seem to erase fine, using a PRO-LOG 9103 eraser (box, timer, tube...)

> I would avoid baking them until you have exhausted other
> options.  Not sure what others think.  This topic has come up before here,
> about putting them outside and all that.  The erasers are all over ebay,
> and the hardware store is full of the correct types of lighting, why not
> make a box that will do the job?I assume there is more to it that
> simply erasing them.
> 
> 
> Bill

Erasing seems to work fine. It's the re-programming them that is the problem.

On Wed, Dec 13, 2017 at 02:49:39PM +, dwight via cctalk wrote:
> When I was at Intel, years ago, I recall the baking was only to repair 
> the retention of the EPROMs. It was not to fix random failures.
> 
> It sounds like your EPROMs have various failures that wouldn't be helped by 
> baking.
> 
> Each time the EPROM is programmed, there is a slight increase in the leakage 
> of the floating gate. This was typical after thousands of program/erase 
> cycles. Baking them repaired the damage to the insulating layer that was 
> damaged.
> 
> Dwight

I don't think these chips have been reprogrammed many times. It seems more
age related, affecting some brands/models in my spares but not others.

The failure mode is the chips erase successfully, but any attempt to
program them fails, and they still test blank and read back "...".
Some of these were chips I erased years ago before putting in my spares
drawer, and some had fine working code on them, but I erased them to 
re-program with a newer version of software on them, to discover I could not.

My stash of TI and NEC 2732s seem to have the disease, but my ST, 
Mitsubishi, and several others program fine.

In the case of a bunch of 2732s, I have tried both a vintage DataI/O 29A
programmer and a modern Batronix programmer, with the same results.
I don't think I have a programmer problem.

I still swear someone in the late 80's had me baking EPROMs in an oven
to restore their programability, but I don't remember the specifics. I 
tried a few at 450F for 15 minutes, but they still won't program.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

EPROM baking

[Mark G Thomas via cctalk]

Hi,

I am working on several projects requiring 2708 and 2716 EPROMs, and
am finding some of my chips will not erase, and some will not take 
a program. I've also learned more in the past week than I wanted 
to know about repairing Data-I/O 29a/b programmers.

I vaguely remember in the 1990s baking such EPROMs in the oven, but
I do not remember temperature or time. I was surprised that Google
didn't turn up anything useful with this info.

I'm sure someone here will have some notes on EPROM baking.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Altair Peripheral Emulator

[Mark G Thomas via cctalk]

Hi,

Does anyone know where I can find the Altair Peripheral Emulator?

Links I have found so far are all dead:

http://home.comcast.net/~forbin376

http://frankbarberis.tech.officelive.com/default.aspx

Mark


-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: Ibm rs6000 7025-f50

[Mark G Thomas via cctalk]

Hi,

On Thu, Jul 27, 2017 at 04:05:56AM +0100, Henry Bond via cctalk wrote:
> I'd be more than happy to buy it, do you think settling for 4.1.4 when it can 
> run 4.1.5?
> Probably a patience moment! 

AIX 5.3 should run on this machine, so why run 4.x?

Here are the AIX_5.3 release notes, which mention 7025-f50:

https://www.ibm.com/developerworks/community/forums/ajax/download/----13948999/d5c75973-f837-4fe1-b0d2-d0aff023a00a/attachment_13948999_AIX_5_3_Release_Notes.pdf

As best I can tell, 5300-12-02-1036 was the final service pack and technology
level. 5.3 CDs shoud be readily available on ebay for cheap. I think I got 
mine for less than $20, and you can probably find the 5300-12-02-1036 SP 
download via google.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: Morrow 8" disk image CP/M uploaded

[Mark G Thomas via cctalk]

Hi,

On Thu, May 11, 2017 at 11:31:21AM -0400, Mark G Thomas via cctalk wrote:
> Hi Bill,
> 
> On Tue, May 09, 2017 at 09:56:15PM -0400, william degnan via cctalk wrote:
> > Hi,
> > 
> > I was contacted though my site by someone looking for a boot disk for their
> > California Computer System S-100 2200 computer with Morrow's Disk Jockey
> > DJ/DMA floppy disk controller.  I checked and found what might be a
> > suitable disk.
> > 
> > I imaged the disk and the file has been uploaded to my web site along with
> > a PDF of the directory the original owner printed and inserted into the
> > disk sleeve. Does anyone have such a drive controller and would like to
> > take a look at this image to see if it's usable?  Uploaded, here:
> > 
> > http://vintagecomputer.net/disk_images/Morrow/
> > 
> > There may be something wrong with the disk.  The label reads
> > 8" Morrow E14 Phil's System Disk Backup 9/22/86
> > Permanent error on boot track
> > 
> > Despite what was printed on the lable I was able to image the disk without
> > error.  I am hoping the error referred to in the hand-written label is not
> > a physical error and can be edited/corrected.  Maybe this disk is
> > salvageable, maybe the error is a BIOs thing.
> > 
> > There was talk about trying to find a diskJockey boot disk on this list a
> > few weeks ago (right?), if so I hope this is useful.  If anyone attempts to
> > read, let me know how it goes.
> > 
> > Bill
> 
> There are at least two different versions of this controller, with different
> ROM decode addresses. It's non-trivial to modify the card -- not just a jumper
> and PROM to change. The boot disk is specific to which version of the
> card. I have the earlier version of the card with the BIOS at E000H, and
> have been meaning to try the images from Herb's disks.
> 
> These cards are nice in that they include a serial port, so the provided 
> CP/M boot disk and CBIOS will boot up to a functional enough system
> to further configure for specific hardware, solving the chicken and
> egg problem with CP/M BIOS and hardware configuration.
> 
> Newer versions of this card have BIOS at F800H, which Mike Loewen has
> images for, which are probably good, for that version of the card.
> It would be helpful if the person inquiring could determine which version
> of the card they have.
> 
> When I was working on this, I found manuals for both versions on Bitsavers
> (I think), which should have enough info to match up with the card:
> 
> 0xE000 Morrow Disk Jockey 2D Floppy Controller Users Manual 1980 rev2.pdf
> 0xF800 Disk_Jockey_2_Model_B_Technical_Reference_Rev_1_Dec82.pdf
> 
> Please feel free to put the person inquiring in contact with me. I'd like
> to get mine booting, and may be able to help them do similarly.

Sorry to follow up my own post, but I realized after I posted this
that the DJ/DMA is a different product than the DJ/2D models I incorrectly
responded about, so I don't have anything to offer here.

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: Morrow 8" disk image CP/M uploaded

[Mark G Thomas via cctalk]

Hi Bill,

On Tue, May 09, 2017 at 09:56:15PM -0400, william degnan via cctalk wrote:
> Hi,
> 
> I was contacted though my site by someone looking for a boot disk for their
> California Computer System S-100 2200 computer with Morrow's Disk Jockey
> DJ/DMA floppy disk controller.  I checked and found what might be a
> suitable disk.
> 
> I imaged the disk and the file has been uploaded to my web site along with
> a PDF of the directory the original owner printed and inserted into the
> disk sleeve. Does anyone have such a drive controller and would like to
> take a look at this image to see if it's usable?  Uploaded, here:
> 
> http://vintagecomputer.net/disk_images/Morrow/
> 
> There may be something wrong with the disk.  The label reads
> 8" Morrow E14 Phil's System Disk Backup 9/22/86
> Permanent error on boot track
> 
> Despite what was printed on the lable I was able to image the disk without
> error.  I am hoping the error referred to in the hand-written label is not
> a physical error and can be edited/corrected.  Maybe this disk is
> salvageable, maybe the error is a BIOs thing.
> 
> There was talk about trying to find a diskJockey boot disk on this list a
> few weeks ago (right?), if so I hope this is useful.  If anyone attempts to
> read, let me know how it goes.
> 
> Bill

There are at least two different versions of this controller, with different
ROM decode addresses. It's non-trivial to modify the card -- not just a jumper
and PROM to change. The boot disk is specific to which version of the
card. I have the earlier version of the card with the BIOS at E000H, and
have been meaning to try the images from Herb's disks.

These cards are nice in that they include a serial port, so the provided 
CP/M boot disk and CBIOS will boot up to a functional enough system
to further configure for specific hardware, solving the chicken and
egg problem with CP/M BIOS and hardware configuration.

Newer versions of this card have BIOS at F800H, which Mike Loewen has
images for, which are probably good, for that version of the card.
It would be helpful if the person inquiring could determine which version
of the card they have.

When I was working on this, I found manuals for both versions on Bitsavers
(I think), which should have enough info to match up with the card:

0xE000 Morrow Disk Jockey 2D Floppy Controller Users Manual 1980 rev2.pdf
0xF800 Disk_Jockey_2_Model_B_Technical_Reference_Rev_1_Dec82.pdf

Please feel free to put the person inquiring in contact with me. I'd like
to get mine booting, and may be able to help them do similarly.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

Re: KDJ11-B PDP 11/73 getting stuck in Exit standalone mode diag #56

[Mark G Thomas via cctalk]

Hi Bill,

> 
> From: cctalk [cctalk-boun...@classiccmp.org] on behalf of Mark G Thomas via 
> cctalk [cctalk@classiccmp.org]
> Subject: KDJ11-B PDP 11/73 getting stuck in Exit standalone mode diag #56
> 
> Hi,
> 
> I picked up an empty 4x8 Q-bus chassis at VCF-East this year. It's
> labelled "USDC CSS-823 Processor System" on the outside. It's not a DEC
> backplane, but the chassis is light aluminum, smaller and in some ways
> nicer than my pile of BA23s. It includes a switching power supply,
> LTC and q-bus termination, and I confirmed it's wired for Q22. I was
> hoping to transplant an 11/83 into it, since it will fit more comfortably
> in my work area. It has lit DCON/RUN/LTC/HALT buttons on the front pane.
> The etching on the backplane says something like "MDB Systems, Inc.
> East Orange, CA 92665"
> 
> Unfortunately, I discovered slots are all wired Q22/Q22, no top ABCD
> (Q22/CD) PMI slots like a BA23. So, not good for an 11/83 CPU wired
> for PMI on slots C-D.
> 
> So, I was hoping I could get my KDJ11-B (quad-wide 11/73) running in it.
> Upon power up or reset I get "Testing in progress. Please wait" on
> the serial console, and the LEDs get stuck on test 56. CTRL-C doesn't do
> anything yet, and my only options seem to be to hit reset, or if I hit the
> run/stop toggle, I can reset to the ODT prompt. This is with either just
> the KDJ11-B in the top slot, or with the addition of a suitably configured
> MSV11-QA in the next slot. If I turn off the LTC on the front panel,
> I get the expected Error 61 M8190 clock error, PC and register values,
> and options to re-run once or loop on test, so I know the LTC is working.
> 
> I confirmed the KDJ11-B works fine in a BA23, getting past test 56. I also
> tried an 11/53 CPU here in the ABAB backplane and that gets past the self
> tests into dialog mode, but I really would like to get the KDJ11-B working
> in this chassis. I do see that a couple traces to the KDJ11-B C-D slots
> besides the Grant Continuity connections. I assume since the KDJ11-B
> has those Grant Continuity connections on slots C-D, it can run in a
> qbus/qbus Q22/Q22 quad Q-bus slot.
> 
> I noticed the FP "RUN" lamp never comes on (and is not burned out), but maybe
> that's normal -- monitoring something on the bus that doesn't happen during
> power on self test.
> 
> Does anyone here have suggestions about next steps in diagnosing this?
> 
> https://archive.org/stream/bitsavers_decpdpaintNov86_5833755/EK-1184A-MG-001_1184maint_Nov86_djvu.txt
> -
> 4.10.18 Exit Standalone Mode (Test 56)
> 
> In the 22-bit mode, the exit standalone mode is checked by using the
> guaranteed timeout address of 17 760 000 to verify that the timeout
> logic works without hanging up the CPU.
> -

On Wed, Apr 05, 2017 at 03:02:55PM +, Bill Gunshannon via cctalk wrote:
> OK, I have the book on that.  You need to determine which backplane you have.
> MLSI-BPA84-TSerpentine A-B-A-B
> MLSI-BPA84-A-T   Serpentine except for slots 6 and 7.
> 
> We'll ignore the MLSI-BPA82 as that's just a dual wide A-B.
> 
> I will see if I can scan the book and send it to you but no promises how
> soon.  It's pretty good sized and my scanning capabilities are primitive.
> 
> bill

I didn't realize the M8190 (11/73) was PMI, and really the same board
as my 11/83. Fortunately, there was definitely no smoke, and the 11/73 
still works fine in my BA23. I think the magic smoke problem might be
more likely if someone plugs a Q22 board into PMI slots, due to the 
unfortunate wiring of those grant continuity connections.

I cannot find anything like BPA84-anything on this backplane.
There is a tiny whale emblem on the trace side of the board saying 
something like "MO__ Quick" under it, though faint, and bold easy 
to read "MLSI-CHASSIS #40040328" close to the end with the power terminals.

I confirmed with a meter that all slots are A-B-A-B, including 6 and 7.

I'm not sure I need the manual, unless it also includes schematics for
the power supply, RTC, and front panel control electronics wiring.

I'm now up and running with a dual-wide M8192 from a batch from a
scrap board guy on ebay, and an M7195 borrowed from another system
for testing.

Next challenge is figuring out the jumpers on an M8043 for SLU console
and seeing if I have or can find a working SCSI controller with a boot 
ROM on it, since I don't have another M7195 and they seem to go for
high prices these days on e-bay when they do show up.

Mark

-- 
Mark G. Thomas (m...@misty.com), KC3DRE

KDJ11-B PDP 11/73 getting stuck in Exit standalone mode diag #56

[Mark G Thomas via cctalk]

Hi,

I picked up an empty 4x8 Q-bus chassis at VCF-East this year. It's 
labelled "USDC CSS-823 Processor System" on the outside. It's not a DEC 
backplane, but the chassis is light aluminum, smaller and in some ways 
nicer than my pile of BA23s. It includes a switching power supply, 
LTC and q-bus termination, and I confirmed it's wired for Q22. I was 
hoping to transplant an 11/83 into it, since it will fit more comfortably 
in my work area. It has lit DCON/RUN/LTC/HALT buttons on the front pane.
The etching on the backplane says something like "MDB Systems, Inc.
East Orange, CA 92665"

Unfortunately, I discovered slots are all wired Q22/Q22, no top ABCD 
(Q22/CD) PMI slots like a BA23. So, not good for an 11/83 CPU wired 
for PMI on slots C-D.

So, I was hoping I could get my KDJ11-B (quad-wide 11/73) running in it.
Upon power up or reset I get "Testing in progress. Please wait" on
the serial console, and the LEDs get stuck on test 56. CTRL-C doesn't do 
anything yet, and my only options seem to be to hit reset, or if I hit the 
run/stop toggle, I can reset to the ODT prompt. This is with either just 
the KDJ11-B in the top slot, or with the addition of a suitably configured 
MSV11-QA in the next slot. If I turn off the LTC on the front panel,
I get the expected Error 61 M8190 clock error, PC and register values,
and options to re-run once or loop on test, so I know the LTC is working.

I confirmed the KDJ11-B works fine in a BA23, getting past test 56. I also 
tried an 11/53 CPU here in the ABAB backplane and that gets past the self 
tests into dialog mode, but I really would like to get the KDJ11-B working
in this chassis. I do see that a couple traces to the KDJ11-B C-D slots
besides the Grant Continuity connections. I assume since the KDJ11-B
has those Grant Continuity connections on slots C-D, it can run in a
qbus/qbus Q22/Q22 quad Q-bus slot.

I noticed the FP "RUN" lamp never comes on (and is not burned out), but maybe
that's normal -- monitoring something on the bus that doesn't happen during
power on self test.

Does anyone here have suggestions about next steps in diagnosing this?

https://archive.org/stream/bitsavers_decpdpaintNov86_5833755/EK-1184A-MG-001_1184maint_Nov86_djvu.txt
-
4.10.18 Exit Standalone Mode (Test 56) 

In the 22-bit mode, the exit standalone mode is checked by using the 
guaranteed timeout address of 17 760 000 to verify that the timeout 
logic works without hanging up the CPU. 
-

-- 
Mark G. Thomas (m...@misty.com), KC3DRE