Search found 82 matches

by bagpuss22
Wed Oct 11, 2017 12:29 am
Forum: General QL Chat
Topic: Bad evenings repairs
Replies: 10
Views: 602

Re: Bad evenings repairs

@Derek, You are correct and that is what has happened, 9v on the 5v line. I did not realise CST put the link in. JUst trying to ascertain what is damaged and what is not. So far 4 x DRAM and a 8049 destroyed, not checked the 8302 yet. Once I know they are all working then I will move onto the logic....
by bagpuss22
Wed Oct 11, 2017 12:19 am
Forum: Compatibles Corner
Topic: CST Thor 1
Replies: 75
Views: 8819

Re: CST Thor 1

I am hoping that I may not have to change too much. My worry would be, if the board would be
better scrapped or rebuilt!

:?
by bagpuss22
Sun Oct 08, 2017 9:09 pm
Forum: Compatibles Corner
Topic: CST Thor 1
Replies: 75
Views: 8819

Re: CST Thor 1

It was a shorting link put in by CST, by the main connector!

So far I have had to replace the 4 x DRAM and the 8049, just the ZX8302 to check and then
maybe some power can be applied.
by bagpuss22
Sun Oct 08, 2017 9:07 pm
Forum: Wanted
Topic: Replacement ROM Image
Replies: 1
Views: 210

Re: Replacement ROM Image

Sorted.

Thank you.
by bagpuss22
Sun Oct 08, 2017 9:04 pm
Forum: General QL Chat
Topic: Bad evenings repairs
Replies: 10
Views: 602

Re: Bad evenings repairs

OK! Just a cautionary tale. If using a QL motherboard from a Thor or unknown origin, check for this> https://preview.ibb.co/cxFQJw/IMG_2422.jpg ON my Thor board the regulators are removed and this link shorts the 7805 input to output. So if you want to use this board in a QL and then add the regulat...
by bagpuss22
Sat Oct 07, 2017 11:21 pm
Forum: General QL Chat
Topic: Bad evenings repairs
Replies: 10
Views: 602

Re: Bad evenings repairs

Hi Derek, I have not got to the Thor cards yet. Still trying to get a stable system to test them with. I was trying to use the Minerva to test the QL mainboard removed from the Thor. Looks like the 5v line was up at whatever a normal QL PSU outputs at DC, 9volt plus! Not sure what will cope with tha...
by bagpuss22
Sat Oct 07, 2017 6:24 pm
Forum: General QL Chat
Topic: Bad evenings repairs
Replies: 10
Views: 602

Re: Bad evenings repairs

Swapped the boards back. Put the regulators back on the board from Rich and cleaned up both boards. Rich's replacement board is now OK and running from the Sinclair PSU. Put the original Thor board back in and I get a black screen. Sooooooo back to diagnosing the issue with the Thor QL mainboard. St...
by bagpuss22
Sat Oct 07, 2017 5:56 pm
Forum: General QL Chat
Topic: Bad evenings repairs
Replies: 10
Views: 602

Re: Bad evenings repairs

OK just found that the board that cooked my Minerva ROM somehow has a short around the 7805! I removed the 7805 and carrier and I still have 0 ohm between the in and out!? Anyone want to look at a Issue 5 circuit diagram and tell me what could cause this as I have been under a magnifying lamp to see...
by bagpuss22
Sat Oct 07, 2017 1:54 pm
Forum: Compatibles Corner
Topic: CST Thor 1
Replies: 75
Views: 8819

Re: CST Thor 1

ON the board removed today I added the regulators I took off the board I was installing to the Thor. I have also noticed on this Issue 5 board I removed, that memory ICs 3, 5, 9 and 10 are getting very hot, +60 degrees within seconds. The screen seems to be constantly changing with different patter...
by bagpuss22
Sat Oct 07, 2017 2:46 am
Forum: Wanted
Topic: Replacement ROM Image
Replies: 1
Views: 210

Replacement ROM Image

Does anyone have a 64K ROM Image with Minerva and Toolkit II on it?

I had one with a jumper to turn toolkitII on/off until the IC fried yesterday
and wondered about replacing the ROM IC only...

Russ

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