If you have a volt meter, you might check the voltage levels coming from the power supply. However, it would have to be in a pretty narrow range -- low enough to make the memory or something fail, yet high enough for the CPU to run properly long enough for the test to fail.
But, probably caps.
Try washing the board. Sometimes the caps leak and the leakage is conductive. Wash the board thoroughly, using your favorite method -- many have been suggested.
Then test again.
If it works after washing, you know it's the caps, and you can get them replaced secure in the knowledge that it's not good money going after bad.
If washing doesn't work, it could still be the caps, but I can't think of any other mostly free tests that require only moderate skill which would make that determination.
The fact is that any 68K machine anyone wants to keep needs the logic board caps replaced at this point. Leaving the old caps in is almost as bad as leaving the original battery installed and putting the thing in storage.
But, probably caps.
Try washing the board. Sometimes the caps leak and the leakage is conductive. Wash the board thoroughly, using your favorite method -- many have been suggested.
Then test again.
If it works after washing, you know it's the caps, and you can get them replaced secure in the knowledge that it's not good money going after bad.
If washing doesn't work, it could still be the caps, but I can't think of any other mostly free tests that require only moderate skill which would make that determination.
The fact is that any 68K machine anyone wants to keep needs the logic board caps replaced at this point. Leaving the old caps in is almost as bad as leaving the original battery installed and putting the thing in storage.