Graphics Card VRAM Chip Replacement Procedure

This is a basic procedure for how to safely remove/replace VRAM chips. This procedure uses a preheater to warm the whole card, but many people also successfully remove/replace VRAM chips using a hot air station alone (which requires a higher hot air temperature). It always looks easy when watching experts do this procedure, and with experience, probably it can indeed become very routine. However, like most procedures, there are risks and I find it’s easy to underestimate the value of experience. So, if it’s the first time you’re trying it, I recommend practising until you feel comfortable on older cards. I am learning too and trying to refine this procedure as I go, so all thoughts are very welcome, please do add comments.

See also Graphics Card VRAM Reball Procedure

(TODO Add pictures. Add reflow process.)

Prep & Tools

  • Hot air station (no nozzle fitted)
  • PCB preheater (nice, allows for lower hot air temps, but possible without)
  • Soldering iron with flat tip e.g. bc3 or similar for cleaning pads
  • Flux
  • Leaded solder & solder wick/braid
  • Suction tool or tweers for chip removal

Before & Tips

These tips are of course based on my limited experience, please don’t take them as expert advice. I am improving, but this is mainly to share the mistakes I have made.

  1. ALWAYS measure the resistance of the Vmem rail before and after (don’t let shorts make things harder!).
  2. ALWAYS cover nearby sensitive components (e.g. electrolytic capacitors) with foil or Kapton tape.
  3. DO clean pads thoroughly and carefully. Plenty of flux. Sweep the pads with a soldering iron with a blob of leaded solder first, trying not to drag the iron on the actual pads, and let the solder ball glide.
  4. DON’T overheat the chip i.e. if using higher heat (e.g. 400-450 deg C), be quicker, if using moderate heat don’t spend too long. The chip can get damaged. I have baked chips by overdoing the heating i.e. spending too long.
  5. DO commit to the ‘side nudge test’ to confirm solder is flowing – I personally had a problem doing this (I feared that I would dislodge the chip or cause solder balls to fuse). However, it’s probably worse to try to guess if the solder is flowing and often wastes time by having to repeat the process. Without the ‘nudge test’ it is easy to underheat (see example here MSI GTX 1050 2Gb) or worse, possibly overheat the chip.
  6. DON’T use loads of flux when soldering the new chip. Just a thin layer all over the pads is enough. Too much flux seems to lead to a higher chance of fused solder balls. I used to do this a lot. It also doesn’t seem necessary to add lots or any flux when removing the chip, doing so isn’t a big deal, but tends to create more mess and smoke.
  7. DO clean the desoldered pads with IPA while the card is still on the preheater (or while the card is still hot), it makes the flux residue much easier to remove.

Chip Removal

  1. Preheat board to about 130-150 underneath and 110+ on the surface (varies a bit)
  2. Apply flux around the chip (optional)
  3. Begin to slowly heat with hot air station set to 350 deg C
  4. Try to raise the temperature over say 30 seconds to 250+, the flux should start to bubble
  5. Then close in and keep heating until it’s possible to slightly nudge the chip easily from the side
  6. remove chip with the suction tool

Pad Cleaning

  1. with the board still, on the preheater and a BC3 soldering iron at 300, add more flux and run the soldering iron gently across the pads and wick gently to get the worst of the solder off
  2. Add some leaded solder to the iron tip and gently ‘float’ the solder iron tip across the pads. Cleaning the tip off in between sides.
  3. Carefully wick away as much solder from the pads as possible (be careful with wider wick not to let it stick and potentially rip off pads).
  4. With card still on the preheater, clean area with IPA using a cotton-bud

Chip Replacement

  1. Preheat board as in chip removal above.
  2. Add a thin layer of flux to pads and to the new chip (heat the chip slightly to spread the flux).
  3. Try to align the chip as well as possible.
  4. Slowly heat as with chip removal.
  5. Set the hot air station to 350 deg C and close in until the chip settles down and repeat the same gentle ‘nudge test’ as in removal.
  6. Allow the board to cool before testing.

Testing

  1. (before powering on) When cool, check the resistance of the Vmem rail is normal. If shorted, the replacement procedure can be repeated (see common issues).
  2. Power on test, if any usable picture is shown (may have artefacts), power down and replace the cooler before further testing.
  3. Consider retesting with mats or tserver.
  4. If all is well, proceed to windows and continue to stress-test etc for validating the fix.

Common Issues

These are issues that I have personally experienced.

  1. Short on vmem rail – One or more pairs of solder balls may have likely joined, possibly there was too much old solder left on the pads after cleaning (see HD 7850 – Attempt 1). Possibly too much flux might increase the risk of this. The replacement must be repeated.
  2. MATS errors on every bit – If this wasn’t the case before replacement, the chip may not be soldered down correctly (e.g. insufficient heat/reflow of solder balls). Example GIGABYTE GTX 1050TI 4GB Card B. A successful reflow may fix this.
  3. Artefacts – If there were previously no artefacts, then this can be a sign of one or more loose solder joints. A possible cause might be that not enough heat was used to get all solder balls correctly soldered. A successful reflow may fix this.
  4. Exact same MATS errors after successful replacement – memory controller faults, faulty connections under the GPU core and broken tracks can also cause MATS/memory errors. This needs more discussion and examples, but this may be identifiable from the patterns and exact errors in MATS with experience. Resolving this is likely beyond this procedure.

Samples & Results

HD 7850 – Attempt 1 – Failure (short / suspect too much solder left on pads)
HD 7850 – Attempt 2 – Cleaned with leaded solder – May have damaged a pad using too thick wick – Chip replacement still successful, card works in windows, need to stress test.
MSI GTX 770 Card B – Attempt 1 – Artefacts and mats shows the same chip has errors.
Zotac GTX 1060 – Attempt 1 – Initially had a picture, then a blank screen with backlight once cooler was replaced, mats shows errors on the same chip

Links to example cards

Here you can take a look at some examples of cards that have been through the above process.

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