VOGONS


First post, by gex85

User metadata
Rank Member
Rank
Member

I have this FX 5900 XT graphics card that I received in one of those "scrap lots". It does not work at all and first I thought it was due to the bulged caps and ordered some replacements for recapping it.
Upon closer inspection I saw that a transistor (?) on the back side of the card was knocked off (but still there). The silkscreen identifies it as Q502. It can't be soldered back in place because the legs are ripped off, so I need to replace it.
Unfortunately I can't really identify it. The inscription is really tiny but readable, see pictures below. I tried googling different variants:
- GOA3T
- G0A3T
- GDA3T
- GOA8T
- G0A8T
- GDA8T
But none of these returned plausible results. The package seems to be SOT-23.

The attachment Transistor2.jpg is no longer available
The attachment Transistor3.jpg is no longer available
The attachment Card.jpg is no longer available

There is a second identical component (Q501) that I could try do de-solder and then measure, but since I do not have special SMD soldering equipment nor extraordinary soldering skills, I'd rather avoid that.

Any help would be appreciated.

EDIT:
After some more googling I might have found two possible candidates:

1. IRLML2502 (fast-switching MOSFET, would make sense) --> Datasheet: https://www.infineon.com/dgdl/irlml2502pbf.pd … 1535668048e2606
The code would translate to:
G = Part No. IRLML2502
0 = Year 2000
A = Week 01
3T = Lot Code

2. HSMP-3890 (single diode, which would not make much sense imo) --> Datasheet: https://media.digikey.com/pdf/Data%20Sheets/A … P-389x-489x.pdf

My retro computers

Reply 1 of 5, by kalohimal

User metadata
Rank Member
Rank
Member

I think you've found the correct one, IRLML2502, which is an n-channel mosfet. It's part of the buck converter, and the circuit right out from the datasheet of the pwm ic ISL6522 is like this:

The attachment isl6522.jpg is no longer available

Slow down your CPU with CPUSPD for DOS retro gaming.

Reply 2 of 5, by gex85

User metadata
Rank Member
Rank
Member

Thank you, good idea to look up this datasheet as well. I'll give it a shot, just ordered two IRLML2502. 😄

My retro computers

Reply 3 of 5, by gex85

User metadata
Rank Member
Rank
Member

Today I found some time to solder on the replacement transistor. Power on - success!

The attachment POST.jpg is no longer available

Some time ago I received this Revoltec VGA cooler as part of a bigger lot. Didn't think I'd even use it one day, but since the stock cooler was missing the aluminium top plate, I decided to give it a shot:

The attachment Revoltec.jpg is no longer available

So this is the end result:

The attachment Result.jpg is no longer available

Completely recapped with Panasonic caps, too. I haven't tested it beyond the BIOS POST yet, but I'm pretty confident that it will be fully working again 😄

My retro computers

Reply 4 of 5, by Doornkaat

User metadata
Rank l33t
Rank
l33t

Nice job! 👍
I'd go with something beefier than that Revoltec cooler though.

Reply 5 of 5, by pentiumspeed

User metadata
Rank l33t
Rank
l33t

If this is very heavy copper heatsink, keep that, I have one like that and it's beautiful.

Cheers,

Great Northern aka Canada.