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| Chimes of death |
Posted by: beachycove on 2013-10-28 19:52:00
I have an LC520 logic board (makes a nice upgrade for a Color Classic, with a 25mhz 68030, 32 bit bus, and 36mb RAM) that gives immediate chimes of death on powering on. This happens whether or not the board is installed bare (without memory sticks), and no matter what RAM/ VRAM sticks are installed (all sticks work in comparable machines from the era). Power-on tests have been conducted in a working LC575 that starts up fine from other logic boards, including another LC520 board that was sold on long ago.
So this one LC520 logic board that I have left is definitely bad.
I would prefer not to throw it out, so I wonder about the theoretical possibility of repair. There is a small quantity of onboard RAM (4MB) and VRAM (512k) soldered on the LC520's logic board, so my thinking is that one of the on-board memory chips is most likely what has died. POST checks RAM and VRAM right out of the starting gate, as I understand it.
Is a proper diagnosis possible or is it just guesswork?
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Posted by: Macdrone on 2013-10-28 22:41:14
It's guesswork, but understand the power supply in the 575 is stronger than the Color Classic and if the 520 board has not been recapped "boom" sad Mac. Weak capacitance will do that.
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Posted by: uniserver on 2013-10-28 22:54:10
the LC-III also does the Insto chime of death with bad caps…
but i have serviced a lc3 before that did that… chime of death.
changed all the caps…. and changed the ram too…
and it still did the chime of death.
that one i gave up on .
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Posted by: Macdrone on 2013-10-29 02:52:40
Can't win them all.
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Posted by: beachycove on 2013-10-29 05:23:48
That's very helpful. The LC520 is basically an LCIII adapted for the AIO form factor, and it has not yet been recapped (only cleaned). I'll give recapping a go and see if there's any joy.
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Posted by: uniserver on 2013-10-29 07:41:43
Can't win them all. True my good man.
give recapping a go sounds like a good place to start.
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