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Re: Replica 1 Ten #36 no go

OK another 6502 received and fitted - no go. Same symptom. Now I'm at the limit of my expertise and it's annoying (especially as I recently built a Z80 CP/M 80's vintage machine with no issue!!!!) and I fear I'm killing chips somehow. I'm see how much it will cost to send back to the US as I really ...
by p20vintage
Jun Wed 25, 2014 1:13 am
 
Forum: Troubleshooting
Topic: Replica 1 Ten #36 no go
Replies: 5
Views: 11437

Re: Replica 1 Ten #36 no go

Hi Next instalment - I found this post http://www.brielcomputers.com/phpBB3/viewtopic.php?f=3&t=1008 which was useful. No 'scope just yet but armed with a DMM that measures frequency I was able at least to do the basic testing mentioned (with the EPROM and RAM removed from circuit). Pin A15 on t...
by p20vintage
Jun Wed 04, 2014 2:19 am
 
Forum: Troubleshooting
Topic: Replica 1 Ten #36 no go
Replies: 5
Views: 11437

Re: Replica 1 Ten #36 no go

OK here's an update… Checked everything as Vince suggested, observed that from pin 6 on the USB board, I was getting 4.9V. Remade the joint at Pin 6 and the power switch, then getting 4.9V at the common of the switch. However when the circuit was switched on this dropped to 4.5V with chips out! Afte...
by p20vintage
May Thu 29, 2014 3:55 am
 
Forum: Troubleshooting
Topic: Replica 1 Ten #36 no go
Replies: 5
Views: 11437

Replica 1 Ten #36 no go

Hi Built #36 last week and got the reset does nothing problem. Checked all my solder joints (a few times) and remade a few. Still no joy. I then checked the continuity from the IC pins (topside of the PCB) based on the schematic just in case I missed a cold joint. Everything checked out EXCEPT there...
by p20vintage
May Wed 28, 2014 1:14 am
 
Forum: Troubleshooting
Topic: Replica 1 Ten #36 no go
Replies: 5
Views: 11437

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