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OK.. might be idea to measure resistance on each CPU pin and make sure you read something to VCC.. (IE 2.2K)Icky wrote: 18 Sep 2018 23:18 OK - I found some bad soldering on the RP6. I cleaned it up and now I am getting bombs but the screen is still all over the place. Let me attach a video
Thanks Exxos for all the help today. I will take a look at these suggestions tomorrow it has been a long day.exxos wrote: 18 Sep 2018 23:21 OK.. might be idea to measure resistance on each CPU pin and make sure you read something to VCC.. (IE 2.2K)
If your using Csync on your cable then the voltage may be to low... https://www.exxosforum.co.uk/forum/viewt ... 204#p10067
Yes great tag team today between you, me and Forgottenmyname and help along the way from a few others.exxos wrote: 19 Sep 2018 00:03 Cool! So we need to get your video stable more than anything next... You might even be able to try the diagnostic cart in the thing.. I mean even if you get a red screen it will give a clue how far down the ROM its getting..
Indeed a long day, we went through a lot today! :cheers:
Thanks Exxos - I too am not around much either. I will take a look at these later tonight.exxos wrote: 19 Sep 2018 09:09 Not going to be around much today.. but some thoughts..
Bridge over R127.. if your video lead as like 330R like in the diagram posted earlier, then the value is likely to high.
Also check V&H sync voltages and waveforms, and also check CSYNC voltages vs a working ST...
You could try swapping the BC337 for a 2N3904 from the donor board.
EDIT: Hi PeteW - sorry am phased tonight. Happy for the suggestions.PeteW wrote: 19 Sep 2018 20:39 Sorry I've been lurking and watching these build threads with interest :)
Does the cable work with a 'real' ST and if so, what's the difference in csync signal between the 2?
Ignore me if I'm talking rubbish 😁