Between the 30th of March and the 20th of April.
I am a computer collector from England and specialise on computer artefacts
>from the 1940s to the 1970s. and would love to attend one of these when
visiting my son in TN.
Many thanks,
peter vp
I've got a piece of gear here with a bad MC858P used as a bus
driver--terminated in 220/330 ohms at the far end.
Given that old DTL is a hit-or-miss proposition, I'm proposing to
substitute a 7438 OC buffer. Pinout's the same, as is Vcc.
Before I get out the soldering iron, any "don't do it" thoughts?
--Chuck
Hi,
I have 4 pcs. IDT49C402 Bit Slices, it is no problem to find a datasheet
for that chip..but it is an problem to find the pinout for the PGA84
Package. In all Datasheets that I've found only DIP68, LCC/PLCC68
PGA68 and CERQUAD68 are listet..
Has anyone a databook newer than 1989 where the PGA84 Pinout is listed?
TIA,
Holm
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> From: Warner Losh
> Do those chips have ROM numbers on them?
I have updated the:
https://gunkies.org/wiki/KD11-E_CPUhttps://gunkies.org/wiki/KD11-EA_CPU
articles with the DEC part numbers for the i) microcode and ii) instruction
decode PROms.
That's not all the PROMs on the Control card - there are effing bazillions of
the damned things (I suspect they used them to reduce the amount of random
logic, so the CPU'd fit on two boards) - but it's most of them.
I have yet to triple-check them, so there might still be transcription error
or two.
> From: Rod Smallwood
> I am sure somebody will come up with the actual images either the
> original files or derived from what we have.
I wouldn't be too sure of that; silence so far. I have reached out to Mike
Douglas, to ask where the microcode dump on DeRamp came from: perhaps the
originator can help with the missing bits. (Although perhaps I should ask Al
K; BitSavers also has the dump, and it's older, so perhaps that copy came
>from the originator.)
> We have narrowed the problem down.
> Its the instruction decode ROM's that are the issue.
> The images of those are whats needed.
All of them? Or is just one failed?
I'm wondering if you've just had a single one lose a bit or two; that's
somewhat common in old PROMs. The chip you reported as failing (E111) almost
certainly couldn't have taken out an instruction decode PROM, it's nowhere
near them.
I ask because we have absolutely nothing on those PROM's contents. With the
microcode PROMs, we at least have the contents in symbolic form (see pg. 15
of MP00082; alas, we don't seem to have the KD11-EA equivalent of Table 7-15
>from EK-FP11A-TM-002), but for all the instruction decode PROMs - nada.
Absolutely nothing.
But if they're _mostly_ there, with the partial contents, and a description
of the failure mode (e.g. 'SETC doesn't set the C bit'), we might be able to
work out what bit got dropped.
Failing that, someone's going to have to volunteer to unsolder a set, and
read them out - at least, I assume that's what would have to be done. Perhaps
a logic analyzer could be attached to an instruction decode ROMwhile the CPU
ran diagnostics, and eventually a complete readout of the contents
accumulated.
Noel
>>> On Tue, Feb 8, 2022 at 6:18 PM Rod Smallwood wrote:
>>> On the M8266 CPU control board a defective 7404 (E111) has killed a
>>> bunch of the PROMs holding the microcode.
That's pretty astonishing; I've heard of PROMs dropping bits over time, but
I'm a bit amazed to hear of a failure in a TTL gate (the 74S04 is a hex
inverter; its gates are on pg. 7 of the M8266 prints - they produce uPC03-08)
taking out a bunch of other gates connected to it.
>> On Tue, Feb 8, 2022 at 7:04 PM Warner Losh <imp at bsdimp.com> wrote:
>> I found
>> https://deramp.com/downloads/mfe_archive/011-Digital%20Equipment%20Corporat…
>> which has the source code...
>>
>> But I couldn't find the tools to use these files to create microcode
>> images.
Actually, the "m8266_ucode.v.txt" there seems to actually be the program that
produced the symbolic dump (which is also available at:
http://www.bitsavers.org/pdf/dec/pdp11/1134/m8266_ucode.out.txt)
It looks like the program is in VHDL or something like that, but it doesn't
seem to have the actual microcode (was it stored/defined in another VHDL
file?); that raises the question of where the actual microcode that it was
dumping was.
It might be worth inquiring of Mike Douglas (he runs the DeRamp site) to find
out where the files in "mfe_archive" came from; perhaps the source has, or
knows of, the file which "m8266_ucode.out.txt" was a symbolic dump of - maybe
>from a complete KD11-EA simulation in VHDL?
If that's not possible,it would be trivial to extract the PROM contents
(well, partial contents - see below) from the "m8266_ucode.out.txt" file;
each uword entry starts with the lines:
***** PDP-11/34a micro code word for MPC = 000 *****
(MSB is left, indented fields generated by expansion ROMs)
micro word........ = 0000 0111 1100 0000 1100 1000 1010 0001 0000 0000 1110 0000
from ROM: E105 E103 E104 E100 E98 E97 E99 E106 E107 E108 E109 E110
The address of each uword is the "MPC = xxx" line; the contents of the 12
PROMs, at that address, are given on the "micro word........ = " line (the
PROMs are 4 bits wide).
If someone explained what format they needed as input for burning new PROMs,
I could easily (like an hour) write a small portable program (using StdIO
only, so it could be compiled and run on _anything_) that read that file in,
and spat out the 12 PROM files. (Most of the dump could be ignored - all the
data that's needed is in that one line.)
BUT (and this is why it would be good to get back to the source of that file),
that's not a complete M8266 ucode PROM dump.
The KD11-EA has a uword address space 1 bit larger than the KD11-E - almost
certainly to support floating point instructions; the KD11-EA adds 'uPC 09'
(although looking its source at the top of pg. 7 of the prints, I don't quite
grok how it is generated - maybe it's fed back through J2 from the FP11-A when
one is plugged in). Anyway, uword addresses run up to 02000 in the KD11-EA,
and the last uword in that dump is 0777.
Interestingly, according to the flow charts of the 'basic' KD11-E/EA ucode in
the prints (indexed and annotated here:
https://gunkies.org/wiki/KD11-E/EA_microcode
in full), they stop at 0757 - but the dump (in "m8266_ucode.out.txt")
contains uwords that are 'supposed' to be blank (per the flow charts),
as well as above 0757.
So that dump must have been prepared from a copy of the 'new' KD11-EA PROMs -
the ones including the floating point ucode. (Note that the FP11-A _also_
contains ucode, intended to control the stuff on the FP11-A; but the floating
point instructions _also_ use the KD11-A for some stuff - e.g. fetching
operands from main memory. Only the ucode address space is shared.)
> From: Warner Losh
> There's a small chance that the tools.tar.gz link on
> http://www.ak6dn.com/PDP-11/M9312/ has these, but that's for a
> different module so who knows.
Right, a _completely_ different card - a boot PROM, not a CPU; totally
un-related - and by a different person (Don North).
But just for completeness, I looked in "tools.tar.gz", and it's just
bootstrap PROM stuff.
Noel
You may recall that, a few weeks ago, I requested parts help (shopping
baskets) for
the Retro Chip Tester Pro that I got for Christmas. Well, today's mail
brought the last
few parts and I have finished and tested it. Wow! The only thing that it
doesn't do is
slice bread. It's great. I've put up a few pictures here:
http://wsudbrink.dyndns.org:8080/images/RCTPro/
I got the 4008 and 1702 adapters with it, but I'm pretty sure that I will
get the rest over
the next month or so. This is the latest HW version with the latest release
software.
Bill S.
PS: Thanks to everyone that helped with parts.
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> So it sermsdectape heads are special. I don?t think Dec would have the desire to make them internally so they probably contractef with a company already set up to do that. Who were the big tape head manufacturers at that time? Does anyone know?
A photo of the back of a TU56 DECtape head can be seen at https://www.pdp8online.com/tu56/pics/head_label.shtml?small .
The head has a label on it that reads:
Western Magnetics
Glendale Calif.
Record
7282
I've never seen a TU56 in person and have no idea if they have separate read, write, and erase heads or some other combo. The "Record" notation on the above head's label hints to me this might be a write head.
I found that and other DECtape photos at https://www.pdp8online.com/tu56/tu56.shtml .
-- Ron
>
>
> Date: Tue, 8 Feb 2022 20:55:31 +0000
> From: Wayne S <Wayne.Sudol at hotmail.com>
> Subject: Re: DECTape head problem
>
> So it serms dectape heads are special. I don?t think Dec would have the
> desire to make them internally so they probably contractef with a company
> already set up to do that. Who were the big tape head manufacturers at that
> time? Does anyone know?
>
We have one from Applied Magnetics Corporation, maybe the one in Goleta, CA.
--
Michael Thompson
On 2/8/22 14:14, Wayne S via cctech wrote:
> Searched a lille bit for Western Magnetics. Here?s a site that has some surplus heads, even a western magnetics onebut probably not the correct one. There is a corporate charter record for Western Magnetics in Minnesota dated 1964. Maybe this is the same company. There?s also a tape head from Michigan Magnetics. Maybe a merged company?
>
> https://www.surplussales.com/Equipment/magnetic-tape.html
>
>
> Sent from my iPhone
>
> On Feb 8, 2022, at 13:05, Ron Pool via cctech <cctech at classiccmp.org> wrote:
>
> ?
> So it sermsdectape heads are special. I don?t think Dec would have the desire to make them internally so they probably contractef with a company already set up to do that. Who were the big tape head manufacturers at that time? Does anyone know?
>
> A photo of the back of a TU56 DECtape head can be seen at https://www.pdp8online.com/tu56/pics/head_label.shtml?small .
> The head has a label on it that reads:
> Western Magnetics
> Glendale Calif.
> Record
> 7282
>
> I've never seen a TU56 in person and have no idea if they have separate read, write, and erase heads or some other combo. The "Record" notation on the above head's label hints to me this might be a write head.
>
> I found that and other DECtape photos at https://www.pdp8online.com/tu56/tu56.shtml .
>
> -- Ron
>
>
Thanks.? Hadn't seen the Minnesota information.? Found some references
but not actual company info.? Did find a reference somewhere it Canada,
but I couldn't tell if it was original or successor company.? At any
rate, no web presence nor telephone numbers found (yet.)
I've dealt with the SurplusSales (of Nebraska) many times.? His prices
are usually pretty high (not obscene, but just not 'surplus' prices I'm
used to.)? However, he is a first-rate dealer and when he says something
is so, you can count on it.? Never had problem with anything I was
willing to *PAY* for.? I scanned the list you provided and found only a
few 'digital' devices, unfortunately.? I suspect from 7 and 9 track mag
tape drives.? I will scan his site and send him a ping so he'll be on?
the lookout.
-Gary
Hi
???????? Jerry Walker and I have an 11/34 under restoration.
We have run into a bit of a problem.
On the M8266 CPU control board a defective 7404 (E111) has killed a
bunch of the PROMs holding the microcode.
Does anybody have or can get images of the PROMs on this board so
replacement devices an be programmed.
Rod
