The Sinclair QL Forum

For Kobe read job

Thanks to everyone for your comments.. well if only I’d changed the ZX8301 first I’d have saved myself a few pounds and everybody’s time!

Swapped out the duff 8301 and popped in the replacement and hey presto, she’s up and running again.

Now I’ve just got to do a proper Kobe of those keyboard led ...

We’ll thanks for the replies..

The 8049’s are definitely good but it isn’t the problem.. I’d bent a pin when fitting so once that was sorted I’m back where I was.. stuck on the F1/F2 screen.

Thanks for your comments Martyn, I’m on the former version of the ZX8301 and I can’t seem to locate the ...

One step forward but !!

I was convinced it was the 8049 so eventually got hold of one (well 2 actually) and replaced it, expecting/hoping thing to at least improve, but with the replacement 8049 in place, it no longer gets as fas as displaying the memory test screen let alone reach F1/F2!! Instead ...

Thanks for the advice

Post Sun Apr 30, 2023 11:44 am

Hi,

I originally posted this as a dead keyboard issue but following some helpful advice, I now realise that there is an issue with all I/O and not just the keyboard. Here’s a potted history:

I replaced the keyboard membrane and I’m doing so dislodged one of the led ...

I’ve now replaced the ZX8302 and it seems that it’s not the culprit..

I’m in the process of getting a readable copy of the circuit diagram so that should help and hopefully I’ll be able to identify the PIN numbers better.

Is it possible for the CPU to be partly faulty in that it’s able to access ...

I have a replacement ZX8302 en-route.. I’ll swap it and see what happens before tinkering any further and I’ll update with the results.

I must do something though as a permanent solution for the poor LED connection.

Cheers

Ok Thanks for that..

I’ve swapped on my Minerva rom and it’s not just the keyboard because the machine hangs after the memory test displaying the Minerva splash screen but where it normally defaults to F2 after a few seconds, it now doesn’t.

It’s over 35 years since I dabbled with electronics so ...

Hi, I’m a newbie here so please forgive any stupid questions.

I’ve just fitted a new keyboard membrane and one of the silly led wires popped out and shorted somewhere (the screen disappeared and locked up). After rebooting the keyboard is totally dead. At least before most of the keys worked. Can ...