bscott@nyx.UUCP (Ben Scott) (09/02/90)
I have tried elsewhere for this info but got no definitive replies, so - The story so far: I bought a used A-500 motherboard (bare board) as-is for $75. When it arrived, suprise suprise it didn't work. I swapped out Denise, Paula, Gary, the ROM and the 68000 and all worked in my other machine, but I got nothing at all through the video port or the RGB output. I hooked up a keyboard and got an error signal of 10 short blinks, 1 long blink, pause and repeat on the power light (note: NOT the Caps lock light, I have the chart for those). I have been able to find no one (and I've called every repairman and hardware guru in town) who has a chart of what the power light blinks mean - one claimed that it was a bad keyboard, but I know (or am pretty sure) it is some kind of error code. (oh, BTW, I once got a green screen for a fraction of a second, but nothing at any other time on the screen) Anyway, a few days later I decided to try again. So I plugged in and it gave me a red screen, steadily, which I considered progress. I did not bother to look up what that meant (I do have the chart somewhere) but began swapping chips again. I would have tried Agnus first if she wasn't such a <w>itch to get out of her bed. As a last resort, I tried swapping the CIAs (8520s) though I didn't see how they'd affect the video circuits and the whole machine. But to my suprise, it asked for a WB disk! I hurriedly hooked up an internal drive and it booted and worked normally. I did not test the serial or parallel ports, though I'm sure one or the other must have been nonfunctional if one of the I/O chips was bad. At any rate, the mouse worked fine and all the memory appeared kosher. I then decided to power down and hook up my A-501 just to see how it would work. However, when I did I got a green screen again, and it would not boot. I took the A-501 out again but still get a green screen. The A-501 (actually it's a clone, EXP-512 PP&S) still works fine. (at long last) MY QUESTION IS: Have I blown the other 8520? Should I just replace them both or is this indicative of a deeper trouble that will just keep eating CIAs until I run out of money (not too far distant at $15 a pop)?? I mean, for $75 I'm happy to have the Denise, Paula, Agnus, Gary and etc. for spare parts, but it'd be even nicer to have a third Amiga as a secondary backup. Can anyone out there diagnose my problem? The board was supposedly working at the time it was taken out of service, and the other two that the same guy had for sale are now working fine for the person who bought them (hi, Blaine). If it's just the CIAs, then tell me and also tell me how to hook up an A-1000 or A-2000 keyboard in case I can't find a cheap A-500 keyboard anywhere. THANKS in advance. . <<<<Infinite K>>>> -- .---------------------------------------------------------------------------. |Ben Scott, professional goof-off and consultant at The Raster Image, Denver| |Amiga UUCP node domain: bscott@vila.denver.co.us Else: bscott@nyx.cs.du.edu| |FIDO point address 1:104/421.2, or call the Arvada 68K BBS at (303)424-9831| |"Don't embarrass us..." "Have I ever?" - Buckaroo Banzai | *AMIGA POWER* | `---------------------------------------------------------------------------'