Sinclair ZX80 / ZX81 / Z88 Forums

Yes, I have a scope and a logic probe

Thanks

Mark.

Hey Mark,

Yes, I just tried a kempston joystick interface (which works on a 48K machine) and it's not working on the +2a.

I guess I'm possibly looking at a faulty ULA then?

Thanks,

Mark.

Which expansion cards / interfaces have you tried? Mark Hi Mark, I've tried the ByteDelight diagnostics card, 2 different V3 SmartCards from Retroleum and a Dandanator Mini - all which work fine on other Spectrum machines (including another 2a that I have). The edge connector has been cleaned, and ...

Hi all, Got a Spectrum +2a (black) that works just fine. It had an issue with a dead RAM chip which I replaced. My issue is that any expansion card that I plug into the back and power up results in a garbled screen once more. I thought it may have been an issue with a faulty Z80 with a bad /M1 line,...

dessony wrote: ↑Fri Oct 28, 2022 11:49 pm Hello everybody,

I have some extension boards for sale.Extension board.JPG

Cheers,
DesSony

You're in the US though.. by the time I pay for the PCB, customs, postage and VAT, I'll need a mortgage!

Thanks,

Mark.

Thanks for confirming that, Mark.

Mark.

Hi Dessony, Your PCB's look different next to the key - each track and pad on the Memopak goes to another single pad. You have 2 pads connected together on your PCB (looks like GND?) - are you sure this would work with the memopak16? EDIT: I've attached pics of the front and back of the Memopak conn...

Hi all, Does anyone know if someone has recreated the little through PCB on the Memotech Memopak 16? The little PCB that's soldered onto the ZX81 connector that allows another peripheral to be connected to the back of the RAM pack? I have one that I picked up that has a broken connector - and someon...

IC25/26 being faulty will certainly cause you issues with upper RAM..

I would socket them both and replace them. Probably find that will sort the issue.

KbJ

Hi 1024MAK

It's a plastic OTP ROM (Intel P27256) I think? (Could be a mask ROM I guess).

I've attached a pic.

Cheers again,

KbJ