It's the ULA on the CPU board.
Freeze the chip and the fault appears. Let it warm up and it goes away.
Ironic that the name of the chip is "XBAD03".



Oh no that's a bit of a blow. I guess with a name like that you could have gone straight for itstephen_usher wrote: Thu Nov 30, 2023 7:47 pm Used freeze spray (well, an air duster upside down) and isolated the fault.
It's the ULA on the CPU board.
Freeze the chip and the fault appears. Let it warm up and it goes away.
Ironic that the name of the chip is "XBAD03".


Pretty sure I have some 27c256s if you want some.stephen_usher wrote: Thu Nov 30, 2023 9:05 pm Yeah. Hehe.
The other problem I have is that I don't have any 27C256 EPROMs, only old 27C64s, 27C010s and a 28C256, which has A14 and Vpp swapped realative to a 27C256. *sigh*


No worries, I have spares if you need more.


I feel your pain, the Quinnterface I have coming was posted on the 24th and took 4 days to get from 'Received by our network' to 'Handed over to the air carrier' where it has sat since the 28th. I expect it to vapourise into nothingness once it actually takes off, and to vanish for days until reappearing in the Royal Mail track and trace.stephen_usher wrote: Fri Dec 01, 2023 10:31 am *mumble* *mumble* Everything I ordered is in delivery hell *mumble*
The capacitors I ordered from RS on Monday (where they said plenty in stock and other stock in Europe) says that it's dispatched "via multi-courier", which means their European stock, in an e-mail which gives a DHL parcel reference that DHL knows nothing about. Also the web site doesn't even say dispatched. I also note that the delivery information for the parts have changed to "delivery: 5 working days" from the "Next Working Day" it had when I ordered. So, the dispatch e-mail(s) were a lie. This means that I can't recap the OPD monitor.
The Microdrive cartridges I ordered from eBay are coming via Evri and so are going to take a week. So, I can't create the OPD standard carts.
I've a few other things which are less urgent inbound also stuck in the courier system. *sigh*
