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-   -   Amiga 500 hangs or crashes while loading Workbench (http://eab.abime.net/showthread.php?t=99701)

memcpy 17 November 2019 20:38

Amiga 500 hangs or crashes while loading Workbench
 
Hello, I'm looking for some help as I have been stuck for a while on this. :banghead

I'm trying to troubleshoot an Amiga 500 (Rev5) that is acting strangely. In short, it has trouble loading any version of Workbench at all. The same goes for some other software as well. I have not found a clear pattern, but symptoms are typically that the loading from floppy hangs after a while, or it drops into some kind of AmigaDOS prompt.

I'm loading all software from a HxC SD-card floppy drive emulator.

What I have been able to load successfully, are some of the demos from Photon's ADF Demo Disk Archive. Around 50% of those maybe. Others fail to load, typically with hang or Guru meditation. The famous "Enigma" demo loads successfully for example, and all graphics and sound are OK.

I have tried loading the "Amiga Test Kit", version 1.5, but this also just hangs after reaching track 3 of 84. (As seen on the HxC display.)

I recently also got hold of the DiagROM (version 1.2) (and EPROM adapter) and have booted with this. I ran some tests, and both CIA chips are working correctly and all RAM (512K chip + 512K fast on trapdoor) is also tested OK by the diagnostics.

The last thing I have done is to run the floppy diagnostics from the DiagROM (yes against the emulator) and it's mostly working fine. Manually reading tracks 0 to 79 works fine, but the whole diagnostics just hang if reading track 80 and 81 (probably also to 84). Maybe this is just a bug in the DiagROM, since this feature is marked experimental anyway.


So now I am wondering what I shall try next...

Thanks for any suggestions!

solarmon 17 November 2019 22:56

Check your power supply unit - measure the 5V and 12V rails and see if they are withing acceptable limits and is steady/stable.

Use another known working power supply if you can.

It could be failing caps in your power supply, or on the motherboard. It could also be dry joints that is causing power issues.

You mentioned about trapdoor memory. Test the A500 without this memory expansion - do you get the same issues?

lesta_smsc 17 November 2019 23:38

I had this issue for 2 reasons. Bad floppy drive reading and also bad chip RAM.

Use SysTest to see if any hardware faults.

memcpy 18 November 2019 19:18

Thanks for the suggestions. :)

I'm running the original power supply and original caps everywhere, so I'll definitely look into that.

Tried without the trapdoor memory, but it makes no difference.
Unfortunately SysTest (Amiga Test Kit) does not load, so I am unable to do any extensive memory tests, only the simple one from DiagROM.

solarmon 18 November 2019 21:57

Also, I would re-seat all socketed chips, inspecting and cleaning the chip pins and sockets appropriately.

Use a proper chip puller for the normal chips, but use a PLCC extractor tool for Agnus. Be very careful when extracting the chips as if it is done wrong, and with the wrong tools it could cause more damage!


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