Repair of a Burned Circuit Board using Grafting Technique

RE: Repair of a Burned Circuit Board using Grafting Technique

DAB — Wed, 30 Sep 2020 18:59:56 GMT

Very good fix John.

Judging when you can fix verses scrap can be a daily challenge to some electronics technicians.

As you have shown, sometimes the decision is obvious and you have to move on.

DAB

RE: Repair of a Burned Circuit Board using Grafting Technique

fmilburn — Wed, 30 Sep 2020 15:39:07 GMT

Hi John,

Such beautiful work. Every detail thoughtfully done such as resealing with masking pant that is the same color.

Frank

RE: Repair of a Burned Circuit Board using Grafting Technique

phoenixcomm — Wed, 30 Sep 2020 15:05:39 GMT

[mention:f80b53cee57c44bc9d7c577d07d7c791:e9ed411860ed4f2ba0265705b8793d05] Cool way to fix a burn. I had a electron microscope's power supply fail in a similar but more dramatic fashion. It let out much magic smoke! my solution was to fab him a brand new board. I made lots of pcbs for folks while I was in college. Thankfully there was a board shop that made very pretty boards right down to the gold fingers. I still have some some of my samples around here somewhere.

~~Cris

RE: Repair of a Burned Circuit Board using Grafting Technique

genebren — Wed, 30 Sep 2020 15:05:07 GMT

John,

Wow! As usual, your work is meticulous.

I have seen this type of grafting applied to very expensive, custom electronics (read military), where it was more cost effective to redesign a small section of the board and then graft the fixed portion into the existing boards (back in the mid 70's). This was all lower power stuff, not heavy, 20A stuff. Back then I worked with some amazing technician and assembly folks who could do things like precision drill multi-layer PCBs (up to 12 layers) and cut inner layer traces without damaging surrounding traces. We had boards that would have multiple surgical 'scars' (epoxy patches) and still function in extreme temperature and vibration environments.

My hat is off to you, on this repair. Well done!

Gene

RE: Repair of a Burned Circuit Board using Grafting Technique

dubbie — Wed, 30 Sep 2020 12:14:17 GMT

I have not seen this approach to fixing a PCB before. It was very interesting.

Dubbie

RE: Repair of a Burned Circuit Board using Grafting Technique

shabaz — Wed, 30 Sep 2020 12:04:49 GMT

Hi John,

Great surgical work on the board!

And nice reminder that such fuse-holders might not always work well over time.

I don't know the regulations on such equipment if it were redesigned perhaps an option could be a resettable fuses type idea (push-button on the back of the unit to reset it) but I guess it cannot always be used such as in this example where you've got more than one fuse (or it's intended to be a non-user replaceable fuse) - the resettable solution would only really work to replace a single fuse.

RE: Repair of a Burned Circuit Board using Grafting Technique

Andrew J — Wed, 30 Sep 2020 08:51:30 GMT

Yes, really interesting. I guess you don’t sell these but would it be worth retro-fitting the clips to boards before they breakdown as part of an offered service to dentists? I suppose that wouldn’t do the warranty any favours though.

RE: Repair of a Burned Circuit Board using Grafting Technique

michaelkellett — Wed, 30 Sep 2020 08:15:43 GMT

Very interesting - thanks.

I'm amazed that the original manufacturer hasn't improved the design over such a long period.

Especially when it can go as badly wrong as in your last picture.

Keep up the good work !