Help me! My C128 want abandon me!!!

[retrobazar]

Hello, I'm experiencing problems with my commodore 128, when starts up in 128 mode there are some flashing dots on the screen ... when GO64 the screen change in c64 mode but i receive the following message

?OUT OF MEMORY ERROR IN 0
READY

instead classic text

**** COMMODORE 64 BASIC V2 ****
64K RAM SYSTEM 38911 BASIC BYTES FREE

I tried to type LIST command but no program listed, when I try to load a directory from the disk drive or a file from datassette the computer freezes.

Can you help me please? ani suggest will be appreciated.

Thank you!

[dabone]

Going from the trouble shooting chart located here...

http://www.zimmers.net/anonftp/pub/cbm/documents/repair/troubleshooting-c128.txt


To me it sounds like....

U38 THRU U53   16 RAM chips (4164)
                4 RAM chips (4464) in later versions.
     Blank screen, no border. Shorted chips will get hot. Will sometimes
produce "garbage" screen, abnormal number of bytes free or "out of memory
in 0" error on startup screen, and program crashes when loading (depending
on what part of memory is bad)... repeatable, ie crashes in same place.

later,
dabone

[retrobazar]

Thanks for your help, fortunately i got a lot of rams of any types including 4164 and 4464, unfortunately I have no patience to desolder 16 chips (!!!) I will try thanks again

[retrobazar]

Opened my c128 and seen that there are 16 x 4264 ram, unfortunately I have only 4164 (i confused 6264 that have with 4264 that not have!!!) . On my datasheet seen that 4164 and 4264 are both 64kx1 with the same pinout, do you think that I can substitute?

[Mangelore]

Instead of desoldering all 16 chips, just let the C128 run for a couple of minutes and gently place your finger on top of each RAM chip.
Chances are the defective one will be much warmer if very hot compared to the others.

If you can't locate it this way, then piggy back (don't solder) a working chip on top of the other 16, one at a time, while powering up the 128 in 64 mode. When you locate the defective one, desolder it and off you go...

Cheers
Fotios

[dabone]

Yes you can use the 4164 rams.


Later,
dabone

[retrobazar]

WOW Mangelore!!! I used your method and found the "bastard" ram at last, the U45 gone but not warmed!!! I'm desoldering it and will mount a 4164

Thanks all!!! My c128 will live again for another 20 years (I hope

Cheers

[retrobazar]

REPAIRED!!! THANK YOU

[RobertB]

REPAIRED!!! THANK YOU

That was fast service!  And a fast repair!

             Truly,
             Robert Bernardo
             Fresno Commodore User Group
             http://videocam.net.au/fcug

[Mangelore]

Well done!

[Andrew Wiskow]

Nice to see that another Commodore computer has been saved! 

[airship]

Nice to see that another Commodore computer has been saved! 

And I'm praying for all the rest!  :angel: