Commodore PET 64K Expansion

[dansretropod]

Hi,

I recently got hold of a 64K expansion board for the PET, however it came with none of the cables need to hook it up:-(. Does anyone know if these cables or similar ones are sold anywhere online? The one that goes into the 6502 socket I'll probably have to knock together myself, but the other two I'm hoping are fairly standard?

Many Thanks!

 

[dansretropod]

Since posting this I've created the 3 cables for this myself as I couldn't find anything similar for sale. So with the cables made, theres just one more problem.

It would seem that the previous owner has snapped off one of the voltage regulators! So, my question is this: Does anybody out there that owns the 64K memory board know what is in VR2 (Next to row A of the RAM banks) so I can get a replacement ordered?


Thanks!

 

[dave_m]

: Does anybody out there that owns the 64K memory board know what is in VR2 (Next to row A of the RAM banks) so I can get a replacement ordered?

If the board uses the 4116 dynamic memory chips, then the following voltages are needed at the 4116 pins:
pin 8 Vdd +12V use LM7812 or equiv.
pin 9 Vcc +5V use LM7805 or equiv.
pin 1 Vbb -5V use LM7905 or equiv.

They are available in several packages like TO3 and TO220 so make sure you get the right package.

78XX

 

[Drea]

On mine it says:

128
Lm340t12
7812

 

[dansretropod]

Thanks Dave/Drea, it will be a 7812 that I need then! When I do get this installed and can power on the PET, are there any commands that I can use to test the extra RAM is working? Will it show 96KB available when it boots to the BASIC prompt?

 

[Drea]

Thanks Dave/Drea, it will be a 7812 that I need then! When I do get this installed and can power on the PET, are there any commands that I can use to test the extra RAM is working? Will it show 96KB available when it boots to the BASIC prompt?

To access the extra ram you must use the los-96 os

http://www.zimmers.net/anonftp/pub/cbm/pet/os/LOS-96/index.html

 

[mnaberez]

When I do get this installed and can power on the PET, are there any commands that I can use to test the extra RAM is working?

There is a RAM test program that will exercise it: http://www.zimmers.net/anonftp/pub/cbm/pet/utilities/index.html

Will it show 96KB available when it boots to the BASIC prompt?

No, there will be no change in the BASIC startup banner. It will still behave as an 8032 unless the expansion memory is specifically addressed. Its operation is described here: http://6502.org/users/andre/petindex/8x96.html

 

[dansretropod]

There is a RAM test program that will exercise it: http://www.zimmers.net/anonftp/pub/c...ies/index.html

Thanks for the link. What is the usual way to get programs from a PC onto a PET 5.25" disk? I guess you would need to own a really old PC. I have an EPROM burner, could I use that to get the program onto disk somehow?

Many thanks!

Dan

 

[for()]

I have an EPROM burner, could I use that to get the program onto disk somehow?

If your EPROM burner can handle 2532 (not 2732!), you could burn an EPROM, plug it into one of the expansion sockets and save it with the TIM monitor. But of course that isn't the "usual" way.

Have a look at ZoomFloppy / XD-2031 / petSD / PETdisk ...

 

[rorypoole]

hi I have just got a 64K expansion board for my commodore 8032, is there any software or games that can use it?