48k Issue 3 Board issues

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BlackFX
Posts: 2
Joined: Sat Mar 14, 2020 6:36 am

48k Issue 3 Board issues

Post by BlackFX »

Hi all

I have an issue 3 here that I have been working on, initially the 7805, TR4, TR5 and a hand full of electrolytics were done for. Having replaced all of those I was faced with an apparent lower ram issue. So that was all replaced, but still no dice.

I did some probing around and noticed that I seemed to be getting CPU CLOCK on A0 on the ROM. I have removed all ICs, lifted R25 and removed TR3 to try and isolate the short and it still persists.

Anyone got any pointers on where to look next?

BlackFX
Posts: 2
Joined: Sat Mar 14, 2020 6:36 am

Re: 48k Issue 3 Board issues

Post by BlackFX »

She's a little fluxy and needs a clean. But I get a measurment of 0.7ohm between the two orange spots - according to the schematic I have they never really even come close.
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