Hi all,
A customer has a problem with an old CNC Mill that uses an LSI11
for control. There is an DEC VT510 connected to the LSI11 as console,
The LSI11 is booting from an RX01 (2?) and uses some basic programm..
pretty much a museum...
The problem is, that on the Sigma Systems serial Card (similar to the
M8043) the AM26LS32 receiver is going bad afer some on/off cycles of the
computer. I've already fitted a socket for the 26LS32..
The AM26LS23 only could tolerate +-7V common mode voltage difference and
seems to be not the best part for RS232..
I've checked the terminal and changed in the meantime the X2 and X
capacitors at the line filter, the protective earth from the Line is
connected to the Pin 7 (singal Ground) of the DB25 Connectors and I
could'nt measure realy potential differences that could be the cause for
the damadge of the receiver chip.
To make it short..chase away the problem I wan't to use some RS232
Opto Isolator in the RS232 Line. I've got a used BLACK BOX SP340A-R2
and an SP400A-R3 from Ebay, additional some Power Injector from BLACK
BOX for powering that with some wall wart that wasn't included.
I've now looking for a Manuals for the BACK BOX SP340A and the SP400A to
configure the dip switches in there. There are 2 DIP Switches with 8
positions each..for configuring the power supply for the opto couplers
from the DB25 connectors it seems. Haven't found anyithing related on
bitsavers, there is blackBox in the communication archive, but nothing
related to the SP340 oder SP400..
Can anybody help please?
Regards,
Holm
--
Technik Service u. Handel Tiffe, www.tsht.de, Holm Tiffe,
Goethestrasse 15, 09569 Oederan, USt-Id: DE253710583
info(a)tsht.de Tel +49 37292 709778 Mobil: 0172 8790 741
I have recently bought a DEC PDP-8/s. It hasn't been powered on for about
40 years before I got it. I cleaned it and did some repairs on it (glued
broken flip-chip handles, replaced all front panel lights, restored the
acrylic front panel to as new condition and built a new switch mode power
supply for +10V and -15V).
After testing each flip-chip individually for dead shorts on the power
rails I reassembled the flip-chips into the backplane and on power up it
shows signs of life, but has a number of problems I will have to debug and
fix.
Does anyone here have the original Engineering Drawings or good PDF scans
of the drawings?
There are reduced copies of the PDP-8/s Engineering Drawings in Appendix A
of the two PDP-8/s Maintenance Manuals on Bitsavers, but I have not been
able to find scans of the actual Engineering Drawings. Some details in the
reduced copies in Appendix A are not legible.
Thank you
Tom
Found earlier today:
https://www.facebook.com/share/16ubJMkAzw/
I was looking for an affordable source of 720K disks before I sold my 5140
so my instinct kicked in haha.
--
Anders Nelson
Bill Degnan had asked in a previous message about the DeVry Trainer that we
exhibited at HOPE_16.
The trainer is labeled: De Vry Institute of Technology Bell & Howell Schools
We don't have a lot of information about it. Like the year that it was
created, who manufactured it, who used it, home many were made, etc. The
usual information that you would put on an info card for an artifact.
Here is a picture:
https://vcfed.org/wp-content/uploads/2025/08/DeVry_Institute_of_Technology_…
Enjoy!
Jeff Brace
> VCF/MARCH will have 5 tables this weekend Aug 15-17 at HOPE (hope.net
> <http://hope.net/?fbclid=IwZXh0bgNhZW0CMTAAYnJpZBExMFdyWUcwTTFHMUkwOHRqNwEeW…>)
> in Jamaica, Queens at St. John's University.
> Please stop by if you are in the area!
> List of artifacts on display:
> Lawrence Livermore (in a briefcase), 8080 processor.
> Heathkit trainer ET 3400.
> TTL Trainer
> Devry Trainer
> 555 Timer
> HP 5036-A
> TRS-80 Model III or IV
> Commodore PET
> IBM P-70 - Luggage
> IBM Portable - 5140
> Pong!
> Atari 5200
> Bally Astrocade
> Fairchild Channel F
> We will be promoting our events and local group.
I'd love to stop by, but $250 is one hell of an entrance fee.
John
VCF/MARCH will have 5 tables this weekend Aug 15-17 at HOPE (hope.net
<http://hope.net/?fbclid=IwZXh0bgNhZW0CMTAAYnJpZBExMFdyWUcwTTFHMUkwOHRqNwEeW…>)
in Jamaica, Queens at St. John's University.
Please stop by if you are in the area!
List of artifacts on display:
Lawrence Livermore (in a briefcase), 8080 processor.
Heathkit trainer ET 3400.
TTL Trainer
Devry Trainer
555 Timer
HP 5036-A
TRS-80 Model III or IV
Commodore PET
IBM P-70 - Luggage
IBM Portable - 5140
Pong!
Atari 5200
Bally Astrocade
Fairchild Channel F
We will be promoting our events and local group.
Jeff Brace
Looking for the 24-pin PC clock batteries, such as benchmarq p/n: PM346006
Mouser and Digikey is out of stock.
Anyone have an adapter or method to make one?
Bill
