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| Macintosh IIci fast chime and no video |
Posted by: NE555 on 2019-07-09 16:09:07
When I turn on the board I get a fast error chime, no video. When I install a ROM sim I will get a green striped screen. Jumper is in . All memory populated or 4 RAM populated makes no difference. swapped for other RAM it makes no difference, either.
The Power up circuit seems fine. So what is next to check out?
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Posted by: bibilit on 2019-07-10 00:44:42
Battery leaked at some point ?
had this exact problem not so long ago.
Turned out two traces were broken under the battery holder, and this is near the Rom chips.
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Posted by: NE555 on 2019-07-10 06:19:43
there is no prominent damage from battery acid. But I'll look at the traces and vias in that area.
thank you for the advise.
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Posted by: NE555 on 2019-07-10 18:01:40
No broken traces under or near the battery tray.
I noticed that having the RAM in or not doesn't seem to make a difference. But taking the ROM jumper out causes the board to do nothing at all.
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Posted by: CC_333 on 2019-07-10 23:00:43
I'm by no means an expert in these matters, but maybe the ROM is corrupted or damaged somehow? Was the SIMM you used compatible? Flashed with the proper ROM?
There also could be broken traces between the ROM chips/ROM SIMM and the CPU.
c
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Posted by: NE555 on 2019-07-11 06:56:02
I used a couple of 512k ROM . They should boot or at least show a gray screen? I also tried the RAM of a good board. to the same effect. If the onboard ROM is bad then using a 512k Should do the trick or not? PSU is known to be good, too.
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Posted by: Bolle on 2019-07-11 14:00:09
So you are getting fast chimes as well with no RAM installed? That means it fails somewhere before it even tries to use RAM at all, otherwise you would probably get slow chimes if RAM there would be problems accessing RAM.
Do you get anything when you use a Nubus video card? I suppose the green stripes occur with a display connected to the onboard video?
I would guess that ROM is fine as you are getting chimes. Does the SIMM you tried contain a IIci ROM or did you use a ROM from a different machine? This could explain different behavior of the onboard video when using two different kinds of ROMs.
I would guess there is a broken trace somewhere. Got any high res pictures of your board? Any obvious signs that it has been sitting with cap goo doing its thing?
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Posted by: NE555 on 2019-07-11 17:33:37
SO yes Even without RAM I will get a fast chime.
The green pattern comes up with a ROM in the socket and internal video and RAM.
I didn't try a NUBUS video card. well I did. But I am not sure that card is actually good. I can take a high res picture, but there is nothing prominent. I even looked it over under the microscope
About the ROM, I tried with an SE/30 ROM
https://www.ebay.co.uk/itm/Apple-Mac-SE-30-ROM-64-Pin-SIMM-Macintosh-820-0241-02-630-4339-Vtg-SE30-/362591668923
The other is a toshiba ROM SIMM it has a number 7788A1. Not sure if that's a SE/30 simm
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