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C128DCR help needed
Hi guys, sorry my first post is a plea for help but i obtained a c128dcr not long ago, its got issues! Wonder if anyone can advise? http://postimg.org/image/e424ziajf/ No keyboard (yet), colors dont flicker and i cant get carts to work, c64 dead test cart puts it into c64 mode but that is all
Re: C128DCR help needed

The different color for each letter on the screen is very psychedelic! :) That being said, why don't you ask master C= repair technician Ray Carlsen for help. Ray has repaired our C128's and C128DCR's.

FCUG celebrating 33 years,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm
July 18-19 Commodore Vegas Expo v11 -
http://www.portcommodore.com/commvex

Hi! Yes ive consulted Rays
Hi! Yes ive consulted Rays guide and the closest I can get to a diagnosis is the 8502 (typically one of the very few ic's soldered in!), everything else seems to work ok, 1571 autoboots a disk, it goes into 64 mode and after hacking a cable together (badly) I managed to fill the screen with characters and scroll it up, the colors are all in the background and the text changes color as it passes the affected area. Really would like to know for certain its the 8502 before getting the iron out though!
Also, just tried my 1541
Also, just tried my 1541 Ultimate 2 in it, had no effect whatsoever, like its not even plugged in, cleaned all the connectors, checked the pins on the pcb, everythings fine. Its the 8502 isnt it folks?
Re: Also, just tried my 1541

macc wrote:

> Its the 8502 isnt it folks?

Have you sent Ray Carlsen an e-mail to verify your diagnosis?

His on-line guide may not be enough,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm
July 18-19 Commodore Vegas Expo v11 -
http://www.portcommodore.com/commvex

Not yet Robert but I was
Not yet Robert but I was going to, just going off his article for my diagnosis, ill send him an email
Had a reply off Ray
Had a reply off Ray suggesting the problem may be two fold, first the graphic problems could be u19 and the cart issue one of the cia's, not got round to desoldering the cia's yet but i managed to do u19, tried two other ic's in there, both the same as the first. Managed to get a c64 diagnostic running off my uiec (no harness attached hence the later errors reported) http://postimg.org/image/42hg5m72v/
Re: Had a reply off Ray

Hopefully, you are getting closer to the solution!

FCUG celebrating 33 years,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm
July 18-19 Commodore Vegas Expo v11 -
http://www.portcommodore.com/commvex

I thought so too when U56 was
I thought so too when U56 was mooted as a possible suspect, Ray even cut the trace from that which led to the color sram on his machine, it then started to behave a bit like mine, replacing u56 however had no effect (I checked the trace too) Anyway, now were thinking VIC or PLA, two suspects I REALLY didnt want it to be! Honestly if anyone here has any ideas please chip in (excuse the pun!) or know of a way to test the two chips without using a cart, maybe a program of some sort or maybe theres a .d64 .prg of a c128 specific diagnostic somewhere?
No further forward sadly but
No further forward sadly but just to update the thread with what ive done since last post, replaced u4 cia to hopefully get the cartridges working again, made no difference. Replaced u20 (4066) on advice over at lemon64, no change. Honestly, I cant seem to make any headway on this at all!
Re: No further forward sadly but

Time to remove the motherboard and send it off to Ray Carlsen for diagnosis and repair.

Truly,
Robert Bernardo
Fresno Commodore User Group
http://www.dickestel.com/fcug.htm
July 18-19 Commodore Vegas Expo v11 -
http;//www.portcommodore.com/commvex

If it comes to it I may just
If it comes to it I may just do that although shipping from the UK might be a factor! A friend who has a flat 128 is sending me a few chips out of his own to try, hopefully I can then either rule in or out certain "big hitters"!
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