Dead 286 Biostar mb-1220ve \ VOGONS

Dead 286 Biostar mb-1220ve

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First post, by TimWolf

Posted on 2021-08-07, 18:42

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Twenty-four hours ago this board was working perfectly fine. Plugging in a new to me IO card off of eBay, I got Magic Smoke From the io card. Shut the unit down and now I get 10 beeps. I have tried removing the 287. Changing out the CPU. Changing out the timing Crystal. Different Ram. Obtaining a new copy of the BIOS. Checking all capacitors and resistors on the board. I still get 10 beeps, doesn't matter if it's the old bios or the new one. Starting to think the chipset is fried. Is there any hope? Thanks for any information.

Reply 1 of 11, by paradigital

Posted on 2021-08-07, 19:32

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Any of the voltage rails shorted to ground?

Reply 2 of 11, by TimWolf

Posted on 2021-08-08, 00:36

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paradigital wrote on 2021-08-07, 19:32:

Any of the voltage rails shorted to ground?

No, none of the rails are shorted. While I was at it I tested the power supply. Only getting -9 from the -12 volt. Not sure if that could cause this. Looking for another power supply.

Reply 3 of 11, by Horun

Posted on 2021-08-08, 01:16

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Low -12v should not smoke a ISA card unless it includes a huge amount of ripple on the order of +/- many volts AFAIK.
Can you post a good picture of the front and back of that IO card ? Maybe we can spot the cause of the short...

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 4 of 11, by TimWolf

Posted on 2021-08-08, 02:02

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Horun wrote on 2021-08-08, 01:16:

Low -12v should not smoke a ISA card unless it includes a huge amount of ripple on the order of +/- many volts AFAIK.
Can you post a good picture of the front and back of that IO card ? Maybe we can spot the cause of the short...

Tried another power supply, and same 10 beeps. Here is the io card. The heat and smell seemed to have been the main ic.

Reply 5 of 11, by TimWolf

Posted on 2021-08-08, 02:08

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Reply 6 of 11, by BitWrangler

Posted on 2021-08-08, 02:40

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Possibly plugging the IDE connector upside down could ground enough to cause smoke, but usually the PSU fails to start.

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 7 of 11, by Horun

Posted on 2021-08-08, 02:43

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Looks like you blew a Tantalum cap, it is missing but the pins remain on both front and back. Is the only thing I see wrong unless it came that way....
that would explain the smell near main Acer chip. None of the IC's look burned but the timer ic NE558 is a bit more faded than the rest but could be just bad printing.
Not sure why that would kill your motherboard unless it was already near failure due to other reasons. Hopefully someone else may have some ideas...

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 8 of 11, by pentiumspeed

Posted on 2021-08-08, 02:56

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Yellow coated axial are solid high density ceramic capacitors adopted from SMD capacitors. Due to dense inter-layers, they fail too.

Tantalum capacitors are physically larger despite the uF rating.

Cheers,

Great Northern aka Canada.

Reply 9 of 11, by PC Hoarder Patrol

Posted on 2021-08-08, 03:03

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If you check other images of the card online, there is no component at that spot anyway

Reply 10 of 11, by Horun

Posted on 2021-08-08, 03:21

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Hmmm true about the axial lead ceramic but it also has a + which ceramics usually do not have a polarity (not saying all but most do not) and if there was not one there then why are there pins soldered there ? Usually missing parts have blank solder points.
Curious minds want to know 😀

Hate posting a reply and then have to edit it because it made no sense 😁 First computer was an IBM 3270 workstation with CGA monitor. Stuff: https://archive.org/details/@horun

Reply 11 of 11, by TimWolf

Posted on 2021-08-08, 05:59

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https://www.ebay.com/itm/363460715166

The cable was on it, when it came. The fdd was untested, also from ebay and was the first use also. The CF adapter I was using was set up on another pc and used for 2 weeks with an ide only isa card, with no issues.

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