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PDP8/A (front panels wanted)

The switchregister was an optional extra.....
I really have to get my 8/A running again, it has a max configuration 128K mem, FPP8A and RL01.
And was used as a numbercruncher, which must be quite rare for an PDP8 !
 
Volker, That is a nice looking 8/a. The rack appears to be in fantastic condition. What all is in it?

I think the most common arrangement for an 8/a was without a programmers console.

The Option 2 board (M8317) has a boot loader rom and dip switch to let you select the boot device. One of my machines boots from the RX01 and the other from the RL01. The second machine was also equipped with a programmers console but it was so clean I doubt it was used much. That machine was used for accounting at a photo processing company as late as 1993 or 1994. I traded two arcade games for it, a stand up Atari missile command and a cocktail table Asteroids game. This particular machine had a 16K core memory board and an EAE so it did not have the 8/a CPU (M8215). It is in one of the short DEC racks.

To boot you flip the power switch and wait for the drives to come ready. You then toggle the boot switch on either the limited front panel or press the boot switch on the programmers console. A fraction of a second later OS/8 is running.

The other machine was one of the ClassIC (Classroom Instructional Computers) built into a desk. From what the seller related he got it at an auction from the University of Arizona, Tucson. It did not have the programmers console but it came with the FPP8 (Floating Point Processor). The two best parts of that purchase are the FPP8 and the fact that It still had the chair that came with the desk assembly. It is a terrible chair and both the chair and desk have not faired well with the passing of time. You turn on the power, close the door on the floppy drive and then toggle the boot switch. The drive makse that terrible clang sound when it loads the heads and a fraction of a second later OS/8 is booted. You then wait for the picture tube in the terminal to warm up enough to read it.
 
Doug, after cleaning it looks quite well, but only from the front. The sides of the rack have some rust. Inside the frame are the cards for the minimal system, 8k core I think, the card for RX-01 and a printercard for the Logabax. Nothing unexpected. Down in the rack is the power control. We had very limited time the weekend and I was eger to fix the 8/e with TD8E they have in display. Now it boots OS/8 again.
The OCM is a small museum where you can get hands on most computers. So when the family comes, the children like the arcade-room and daddy the pdp-room. We have to enlarge the pdp-room and I was quite successfull to find some hardware this spring. Now there is a further 8/e, the 8/a and a 11/23+ to bring into function, not only display.
 
Nice! Oldenburg is about 2 hours driving from here... :) Here in Zwolle we have Bonami game computer museum, but they have machines like the straight 8, PDP12 and many more really old machines.

About the PDP8/A, I know the octal panel was an option. But I'd love to have the 8/A with all the options... Doesn't matter if it will cost a few bucks... It will probably be the only 8/A I ever have, so it has the right to be good looking... :giggle:
 
Maybe we organize a meeting in Oldenburg later this year. We had a first one some weeks ago with Jörg Hoppe tutoring his Unibone and repairing the memory of a 11/34. I will let you now when we have a date.

Are the computers in Bonami in working condition? Would be very interesting to "play" with the PDP-12. I have around 100 LINC Tapes with my PDP-12, but I'm far away from having this beast running. Would be fun to see whats on them. Do you know the serial number of the PDP-12? I would like to find out if the serial number, the backplane (lower Plane 6 or 8 rows) and drive type (2 TU-55 or one TU-56) are going together.
I would swap my 8/a for a further PDP-12, even with 2x 16k core! Really. ;-)

Have fun,
Volker
 
There is a plan that I'm going to help Rinus at the museum to get the 12 up and running again. But this school year was so busy that I didn't even have time for my own machines... I think (hope?) next year will be a bit easier...

Searching for a PDP8/A front is the first thing I did to start with my hobby again...
 
DougIngraham said:
Volker, That is a nice looking 8/a. The rack appears to be in fantastic condition. What all is in it?

I think the most common arrangement for an 8/a was without a programmers console.

The Option 2 board (M8317) has a boot loader rom and dip switch to let you select the boot device. One of my machines boots from the RX01 and the other from the RL01. The second machine was also equipped with a programmers console but it was so clean I doubt it was used much. That machine was used for accounting at a photo processing company as late as 1993 or 1994. I traded two arcade games for it, a stand up Atari missile command and a cocktail table Asteroids game. This particular machine had a 16K core memory board and an EAE so it did not have the 8/a CPU (M8215). It is in one of the short DEC racks.

To boot you flip the power switch and wait for the drives to come ready. You then toggle the boot switch on either the limited front panel or press the boot switch on the programmers console. A fraction of a second later OS/8 is running.

The other machine was one of the ClassIC (Classroom Instructional Computers) built into a desk. From what the seller related he got it at an auction from the University of Arizona, Tucson. It did not have the programmers console but it came with the FPP8 (Floating Point Processor). The two best parts of that purchase are the FPP8 and the fact that It still had the chair that came with the desk assembly. It is a terrible chair and both the chair and desk have not faired well with the passing of time. You turn on the power, close the door on the floppy drive and then toggle the boot switch. The drive makse that terrible clang sound when it loads the heads and a fraction of a second later OS/8 is booted. You then wait for the picture tube in the terminal to warm up enough to read it.
Click to expand...
Speaking of the DEC CLASSIC... I just got one in real minty shape - it's completely spotless inside and the LA35 is brand-new, never been used!

It's complete with all of the original documentation, software, VT50H, LA35, etc:
1687300595744.png
1687300722821.jpeg

1687300779650.jpeg

Board compliment: M8655, M8357, M8315, M8316, M8317, G649/H219, G649/H219, and 303-0112-000A (Monolithic systems -- 8K semiconductor memory system)

It is a bit strange that it has a combination of core and semiconductor memory - 24Kw total. The only other oddity is the missing fans from the RX01 drives -- not a huge deal to replace, but strange that they're missing.

-Chris
 
cchhrriiss11 said:
Speaking of the DEC CLASSIC... I just got one in real minty shape - it's completely spotless inside and the LA35 is brand-new, never been used!

It's complete with all of the original documentation, software, VT50H, LA35, etc:
View attachment 1259329
View attachment 1259330

View attachment 1259331

Board compliment: M8655, M8357, M8315, M8316, M8317, G649/H219, G649/H219, and 303-0112-000A (Monolithic systems -- 8K semiconductor memory system)

It is a bit strange that it has a combination of core and semiconductor memory - 24Kw total. The only other oddity is the missing fans from the RX01 drives -- not a huge deal to replace, but strange that they're missing.

-Chris
Click to expand...
Interestingly enough, when consulting the original operator's manual, the RX01 floppy drives indeed did NOT have fans on the back (in addition to the blowers on the top of the spindle motors)! As can be seen here:
1687315254146.png

Still have to get these manuals scanned....

-Chris
 
m_thompson said:
The VT5-52 looks normal, except for a larger power supply, serial console cable to the PDP-8, and power connector for the PDP-8.
I haven't checked to see if the cast base is deeper on a WT-78 vs. a VT-52.
Click to expand...
Thanks for the photos. It is interesting to see the many wire links on the PCBs in the first photo.
This was used to route all connections a single layer PCB. It was done very neatly.
 
Roland,
i could possibly exchange the spare boards from the KC8A programmer for other PDP parts with you.
I don't have the frame, it wasn't there. Unfortunately, the 0 key is broken off and other keys are minimal broken. But it can be repaired for sure.
The Programmers Console was shipped by DEC in Netherlands in 1977 according to the package. I bought the Programmers Console myself on Ebay Netherlands Silverster 2012.
I myself have an almost complete PDP8A-625BM with KC8A panel, 2x16K core memory, rare RL8A controller, RX01, semiconductor memory, serial ports...
As you can see from the pictures, I had to build the Limited Console in a PDP11/03L panel as I only have a damaged board without the front panel.

Jonny

KC8A-1.png
KC8A-2.png
KC8A-3.png
PDP8A-1.jpg
 
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