Baking HD 4870

Another go at baking a broken GPU.

This time it seems that I finally overdid it

And it looks like it... 
Yummy smelly soldering flux, anyone?
Model: Radeon HD 4870 / Sapphire HD4870 512MB (the red one)

Price: 5,99 EUR incl. shipping (ebay.de)

Symptom: Artifacts, hardware not properly detected

Ye Olde Artefacts.
Cool mouse cursor though.
I baked this one twice:

1. On the first go I used somewhat lower temperatures than usual. Cranked the oven thermostat up to 190 °C, then waited about 15 minutes after the thermostat reached target.

Video card in a metal tray, top tightly covered with aluminium foil (see picture further below)

Before the baking:
an awful lot of stinky soldering flux.
Now, I have to admit, I kind of lacked the concentration on this one. I really wanted to get an accurate estimation of the oven temperature, so attention was all about the thermometers I had set up.

It turns out to be not at all that easy to make sure a certain temperature is reached *inside the tray*, especially as it is covered with foil. I measured 190-ish temperatures with the "Salter" thermometer (using its ~1-inch long probe) near the top heaters of the oven, but the analog one next to the tray only ever got to about 160 °C.

No, I didn't bake the wooden one to 190 °C

I imagined that the max temperatures inside the tray may be even lower than 160 °C, but anyway that should do for the moment, I thought.

Cleaned up the card, assembled the cooling and installed it on the test PC.

No artefacts, the card now worked just fine!

For only two hours...

Ran PassMark 3D tests a few times, and at the 3rd or 4th run I already got the black screen.

It might be curious to mention that I had upped the fan RPMs quite a bit, and temps were only around 40 °C at that time. Pretty low temps for a GPU to die, heh?

Anyway, I thought, I just baked the card at too low a temperature. I bought myself yet another thermometer and did the

2. The second go

Now here, this looks almost like science
This new thermometer also had an inch-long probe, but because of being all-metal I could just stick it on the tray and right into the oven.

First I tried a dry run together with the round one from the last baking. New thermometer stuck like on the picture, old thermometer sitting inside under the foil. After some time in a ~200 °C oven, the temperature inside the tray turned to actually be about 10 °C higher than measured on the probe thermometer sticking out of the foil! Looks that after some time, the temps inside actually catch up.

So I put the Sapphire HD4870 inside the tray (together with two unlucky Galaxy Edge N915fy boards). Crank the thermostat to a bit more than 200 °C and watch that thermometer closely.

All in all, I think I baked the cards about 20 minutes after the thermostat reached the target. The (stuck) thermometer showed values up to 210 °C, which might have meant temps of 220 °C or even more.

After that I opened the oven and let it cool as usual, them brought it out to lose the awful smell.


Can anything worse happen to a video card?
Sure, like random ceiling paint fall on it while cooling down.

Brush the paint off, clean up some of the soldering flux (did I mention how bad the stuff stinks?), put on the cooling and test it.

Nope. Cooler spins, radiators heat up, but no picture this time.

Was 220 °C too much?

Seems that, for the first time, I baked a card too hard :))

Whatever, that was fun.

As I am thinking of it, I suspect the card having been baked a few times before I got my hands on it. The stickers on the PCB weren't exactly mint.


Stay tuned to learn about some laptops that actually worked after baking.


DISCLAIMER:
- Baking electronics in your oven can damage them.
- You can poison your oven with toxic fumes.
- You can poison yourself.
- You can burn your house.
- Do it at your own risk. Stay sharp while at it.

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