Re: Diagnosing a C64 problem

Christian Lott schreef:
On Fri, 6 Jun 2008 03:35:42 -0700 (PDT)
drevin@xxxxxxxx wrote:

I also did another RAM test: loaded a "non-working" program into
memory, then instead of typing RUN, saved the program from memory to a
disk. When I compared the saved file with the original, the contents
matched exactly. Not even one byte of difference. I'm starting to
think more and more that the RAM isn't faulty. In addition to this,
the machine has passed 2 different RAM hardware tests.

Have you tried a different power supply? I'm not an ee but.. maybe a ps can burp every now and again. The reason why the fastload makes the program run is because it's pulling more power - maybe the correct amount of power to not cause the ps to burp. The reason why games fail at exact places may be because they're using the controller chips heavily, upsetting the ps. Total guess. Good luck.

If it would be related to the power supply, I would expect random crashes instead of perfectly reproducible crashes the OP reported. I seriously doubt that a fast-loader really makes a difference w.r.t. power consumption. The C64 always runs at full speed with all circuitry active regardless whether it is doing something useful or not. Assuming no datasette is being used, I expect the power consumption to be pretty constant. This is unlike PC's where the power consumption does depend on the workload. Nevertheless it might be worthwhile to swap power supplies just to be sure.

Loading and saving a program does prove only that the part of RAM in which the program was loaded is not corrupt, assuming the comparing was done on another system, otherwise the test proves exactly nothing. However when running a program other RAM areas may be used (e.g. due to decrunching, memory buffers...etc).
.

Relevant Pages

  • Re: Diagnosing a C64 problem
    ... which the program was loaded is not corrupt, assuming the comparing was ... decrunching, memory buffers...etc). ... RAM, not just the area used for loading the program. ... areas" are faulty the program can crash. ...
    (comp.sys.cbm)
  • Re: Diagnosing a C64 problem
    ... which the program was loaded is not corrupt, assuming the comparing was ... decrunching, memory buffers...etc). ... So if I understand right the crashes can still be caused by RAM, ... areas" are faulty the program can crash. ...
    (comp.sys.cbm)
  • Re: Windows uses 4 GB? Really?
    ... I bought 4 GB of RAM because I thought it would speed up my system a bit. ... Some info that is posted here as reference seems to suggest that it is a Windows issue, but others seem to suggest that it is also a hardware issue. ... "I have install total 4GB memory on my motherboard. ... On a SLI system, since PCI-Ex graphic cards will occupy around 256MB, another 256MB will be occupied after you install a 2nd PCI-Ex graphic card. ...
    (microsoft.public.windowsxp.general)
  • Re: Computer wont boot up after installing new RAM
    ... I even took a look at an old Gigabyte motherboard ... DDR2 memory stick, the notch does not line up. ... "To install the memory module, ... into the motherboard RAM slots. ...
    (microsoft.public.windowsxp.hardware)