PhilCs blog / the latest things hes broken(fixed)

[PhilC]

Well I guess I shouldn't have been surprised but the C64 still doesn't work correctly. There is no life from the keyboard and unless you are booting to the dead test or diag test then it doesn't do a whole lot else.

I guess I'll have to get the scope out and probably desolder a few more things yet.

[stephen_usher]

Dead CIAs?

[PhilC]

Dead CIAs?

That’s what I’m thinking, I think I have at least one spare, so could swap them out one at a time and see.

[PhilC]

So it's not the CIA chips, having a quick scope around I see no activity on the /CS lines which go through a 74LS139 which has plenty of activity on the inputs but nothing on the outputs. Guess I'll have to order yet more logic chips for stock then.

[PhilC]

So in between waiting for another logic chip for the C64 I’ve been doing a bit more assembly on the Open128.

So far today we’ve soldered in all the chip sockets and populated them with chips, all except the SID which seems to have gone missing.

Then soldered 90% of the caps, leaving a few odd values to sort out. I hate the finding one cap or resistor for builds like this.

So just the suppressor caps, the resistors and inductors to do and I’m about finished.

Hope it works after all this I know, it’s a C128, there’s no chance of that.

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[rubber_jonnie]

So in between waiting for another logic chip for the C64 I’ve been doing a bit more assembly on the Open128.

So far today we’ve soldered in all the chip sockets and populated them with chips, all except the SID which seems to have gone missing.

Then soldered 90% of the caps, leaving a few odd values to sort out. I hate the finding one cap or resistor for builds like this.

So just the suppressor caps, the resistors and inductors to do and I’m about finished.

Hope it works after all this I know, it’s a C128, there’s no chance of that.

IMG_3008.jpeg

Very nice, I like the purple board, looking forward to seeing it running.

[stephen_usher]

It is very... purple!

[PhilC]

And a bit of a success with the old C64 today. Swapped out U15 for a new 74LS139 and now the cart and everything else works as it should

[rubber_jonnie]

And a bit of a success with the old C64 today. Swapped out U15 for a new 74LS139 and now the cart and everything else works as it should

Splendid.

[PhilC]

And here it is in its fully working splendour.

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IMG_3024.jpeg (394.3 KiB) Viewed 1072 times

A total faulty chips were:

1x PLA
1x Screen Ram
4x logic chips, u13,14,15 & 25.

And a fair bit of knowledge gained whilst fault finding.