Unknown Stack cartridge

[Neo-Rio]

Found this Vic-20 cartridge the other day. It's got a STACK label on the bottom, but I have no idea what it is or does.

All I know is that STACK had a bunch of utility cartridges, of which this is probably one of them.

Plugging it into my VIC-20 displays that the available BASIC RAM has increased to 6655 bytes (so it's probably a 3K expansion)... but aside from that I notice nothing different on power on.

Does anyone have any instructions or way of determining how it is used?

[Neo-Rio]

Some pictures of the cart.

[Neo-Rio]

I did some searching around for information on these carts.
I have at least determined that it is not Vickit 2.
http://www.nemetzpower.de/Denial/VICKIT-II.pdf

SYS 45056 does nothing.

[Neo-Rio]

My curiosity got the better of me, so I opened the cart shell.

There's no ROM in there. So it's only just a RAM expansion with a cart pass-through port?
Seems like a lot of chips for just 3K extra.

Looks a bit like the Stack Storeboard: http://www.computinghistory.org.uk/det/ ... toreboard/
...but obviously there's nowhere to add more RAM or add a ROM. It's just +3K and that's yer lot.

[wimoos]

These RAM chips are the good old 2114's. They are 1024x4 bits. So, 6 of them are arranged on the board as 3072x8 bits.
(As you can deduce from the wiring pattern on the left in the second picture, where the datalines are divided 50/50 over the two rows of 3 chips).

These are used as base memory in many VIC-20s. In mine I have soldered six 2114s piggyback on existing ones on the motherboard (in 1984!).

Regards,

Wim.

[Neo-Rio]

I suppose RAM exapnsions aren't worth much, but I guess they have a use because they can be gutted for spare parts in case my VIC's memory blows.

[Mayhem]

RAM expansions no, but I've never seen that cart before, so it might be worth something. I'm guessing the pass through is so you can possibly run another 8k/16k on top, or another Stack utility cartridge.

[srowe]

According to https://archive.org/details/your-comput ... ne-1982-08 (pg 26) it looks to be a "Low Cost 3K Memory"

[Mike]

Does anyone have an idea, what that extra TTL on this cartridge is supposed to do?

[srowe]

Looks to be a NAND gate with the output connected to /WE of the RAMs. I can only trace one input, probably to the /VRW.

[Neo-Rio]

According to https://archive.org/details/your-comput ... ne-1982-08 (pg 26) it looks to be a "Low Cost 3K Memory"

Interesting. So that solves this mystery!