Posted By
SVS
on 2002-07-15
 |  1551 diagnostic flashes
Does anybody know the meaning of the start-up diagnostic led' flashes of 1551?
My second (and last) drive entered into fault today and I *must* to repair it ASAP in order to produce something during next holidays.
Thanx
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Posted By
JamesC
on 2002-07-15
| Here's info for the 1541....
on which the 1551 is based. I would presume that Commodore, in an attempt to reuse as much code as possible, used the same blink codes between the 1541 and 1551.
1541 Power Up Flash Codes
Now, if one has a 1581, the codes are different because the DOS was rewritten. 1581 power up codes can be found at this link.
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Posted By
JamesC
on 2002-07-15
| Either way...
you should be able to take the (good) circuit board from your other 1551 (the one with the bad disk mechanism) and combine with the good mechanism in this 1551 (with a circuit board problem) to still get one decent 1551.
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Posted By
BushRat
on 2002-07-15
| What was the error sequence?
Valentino, what blink code were the lights showing? Those interface contacts are well known for junk and oxidation buildup, that you can clean. If it indicates a ROM failure, check to see if the Roms are Eproms (the covered windowed chips) if they are you may just need a new set of Roms. Commodore supplied many of their 1551 drives with Eproms that tend to lose their code after 7 to 10 years, from internal leakage.
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Posted By
JamesC
on 2002-07-15
| *MY* 1551 :)
has ROMs complete with part numbers stamped on just like inside the Plus/4. If SVS does have a ROM problem I think he has an EPROM burner to make a new EPROM to get him by.
I was just pointing out that he has one 1551 with a bad read/write assembly, that he could swap circuit boards with.
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Posted By
BushRat
on 2002-07-15
| Yup
That's the first step, James, The swap should get him going again. I was curious just what his diagnostic lights were indicating. I figured he either had, or had access, to a burner if he had the Eprom version. By the way, what are the part/revision numbers on your roms and what did you ever figure to be the glitches you were having when you originally got your 1551?
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Posted By
SVS
on 2002-07-16
| Thank you 4 yr. replies
The blinks are 4, then maybe it's Eprom 2 (I mounted the expanded O.S. that allows 840 Kb). I'll try to put original Roms.
Cheers.
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