A600/M-Tec A630 instability

[Damion]

I finally got a chance to play around with an A600/M-Tec 630 combo I picked up last year, and I'm finding it has some issues. :/

Basically, the thing suffers from random lock-ups and reboots. All I have to do is fire up the 3.1 "Blanker", and it's only a question of time (a few hours at best, usually a few minutes) before it crashes.

I've tried both an A500 brick, and a 360W ATX PSU.

It's not IDE related, as it'll do it straight from 3.1 floppies.

Although it doesn't get hot anyway, I pointed a huge fan right at the '030, no difference.

I cleaned all the contacts where the card interfaces with the A600 68K, have re-seated it several times, and even gave each pin on the M-Tec's PLCC socket a very gentle nudge outward.  

Thinking the '030 might be stressed (seems most of these are overclocked 33 MHz parts, no 40 MHz QFP '030 exists), I de-soldered the oscillator, installed a nice machine-pin socket and clocked her down to 30 MHz... no change.

I haven't tried an extensive test with the accelerator disconnected... but, it doesn't yet crash without it.

Turning off all cache, no fastrom, etc, "seems" to reduce the frequency of crashes.

I'm thinking my next step should be to replace the caps on the A600 mobo. Any other suggestions from those who have experience with similar hardware?

[Damion]

Thanks for the input gents, much appreciated. :pint: I'm glad to hear that the M-Tec is generally a stable unit.

I'm also leaning towards bad caps on the motherboard. At this point I think I'll buy a PAL board (would rather have one for demos anyway), replace the caps on both and keep the NTSC board for a spare. I'll update here when I finally get it sorted.

[Damion]

marcfrick2112 wrote:
-D-: Just my 2 cents, I wouldn't insert/remove the A600's accel. any more than is absolutely necessary, I had heard that the prongs that lock in place over the 68000 have only so much 'life' in them.  ( my dad had a 600 with '030 accel. for some years, can't remember the specifics tho...)

Thanks, I'll keep that in mind. Worse case scenario I'll replace the socket, but hopefully it won't come to that. (I get real nervous putting an iron near old, almost irreplaceable Amiga HW.) Anyway, I'm determined to fix it, one way or another. ;-)

[Damion]

Finally got back to my A600/'030, and am happy to say it's now running 100% perfect. :-)

The caps under the floppy had leaked so badly, I decided not to bother fixing the motherboard. Same with the second board I bought on ebay... some of the pads were simply destroyed.

Third time was the charm. This time a Rev 1 board (woot!) from a UK seller. The caps under the floppy had also leaked, but after removing them and the nearby IC, and cleaning with some baking soda/distilled water, the board was thankfully 100% untouched. Replaced all caps (PITA, as the Rev 1 boards have much smaller smt land sizes than the others), the corroded L347M IC, and the POS Jamicon caps on the M-Tec with some Nichicons. Initially the hard drive light didn't work, which turned out to be a little transistor near the connector for the activity LEDs.

Anyway, I'm so pleased it's working now. :pint: