Radeon HD3850 AGP repair \ VOGONS

Radeon HD3850 AGP repair

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First post, by Retronerd878

Retronerd878 Offline

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Joined: 2023-11-14, 13:02

Got this HD3850 that doesn't want to post at all. Even with a secondary PCI card, no image on the working VGA adapter.
I found some missing components. If someone knows the values that would be great:
C580
C519
C471
C117
C63
C614
U7

U7 was knocked off and holding on just by one pin. I managed to straighten it and solder it back. However, I think that made it worse. When U7 was not connected, the PCI post analyzer card went further to code 2A 20. But now, after soldering it back in place, the post code cycles through just one code and settles at D1 D4. Maybe U7 is bad from the hit and needs replacing. The marking on U7 is Z08L

Reply 1 of 4, by Retronerd878

Posted on Today, 11:06

Retronerd878 Offline

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Joined: 2023-11-14, 13:02

Only 5 attachment per post. Here the last 2 pictures.

Reply 2 of 4, by Retronerd878

Posted on Today, 14:49

Retronerd878 Offline

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Posts: 123
Joined: 2023-11-14, 13:02

On the 2nd picture I measured the cap that was loose (C519) and it measured 1.2 uF. Isn't that kind of high for a 0402 cap? I'm asking because it doesn't look particularly damaged but it gave me a hard time to get a reading out of it.
I also took off and measured C456 and it's 120 nF. Judging by the pattern I'm assuming that the missing C471 is also 120 nF

On picture 5, i took off cap C614 off and it had the one pad loose. I tried to measure it and i got all sorts of values ranging from 50nF to 150 nF. I don't know if I can trust these measurements but it smells like a 100 nF cap to me.

Regarding U7 I measured the voltage of the pins and looks like some sort of 5V to 3.3V converter that is working properly. Attached picture with voltage.

Reply 3 of 4, by Beerfloat

Posted on Today, 16:38

Beerfloat Offline

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My smartphone camera isn't the new hotness it once was. Hope you can make out what you're looking for.

Reply 4 of 4, by Beerfloat

Posted on Today, 16:38

Beerfloat Offline

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Joined: 2023-07-17, 22:07

.. and finally U7

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