DIY repair on a vacuum cleaner circuit board

[Walter]

A mate had a short circuit on his Shark Navigator vacuum cleaner. We spent some time trying to get a local electrician to do a board level repair, but couldn't find anyone to do it. We called the Shark people and their solution was to trade the whole unit in and they would sell him a new one, because they don't have the parts.  Since this was 6 years old, I said we aren't going to lose anything by me trying (and I've said elsewhere, I'm not a handyman).

I knew it was a relay and diode that had blown, as I could see it, and using a multimeter I could see all of the other parts were ok, and all of the circuit paths were fine.

So I watched a few Youtube videos on circuit board repair (I've never done this before, and was convinced I was likely to make it worse - I'm OK at makiing a circuit), and I desoldered and removed the broken bits:

You can see the burned bit.  Underneath, the copper had been ruined at these spots this was my big fear at repairing, because scraping the circuit to expose more copper wasn't something I was confident at doing- I've ruined circuit boards before by using too much heat.  But I did it. In this photo you can see the broken copper:

Cleaned the burned bits with isopropyl alcohol.

The diode was a standard 1N4008 (and I have about 100 of them) so that was easy to solder in.

The relay was $7.95 locally bought.

Here's the fixed circuit so you can see my soldering:

Finished:

and it all works.  About 2 hours taking it apart, fixing and putting it back together.  $7.95 versus $400.00? No contest

[Walter]

@r23on  It was a few years ago, but yep, 1.5KΩ from memory.  Sorry, but not going to take my mates Shark apart to verify

 We did find some similar circuits (used) on eBay, although some are obviously earlier or later variants.

I will say, my mates vacuum cleaner is still going strong 3 years later, so I call that a win. 

[r23on]

The problem was the only colour that I could make was the green hence my call. it great when we fix a problem and its still working one feels good

[MikeTNZ]

"We spent some time trying to get a local electrician to do a board level repair."

Ha Ha Ha Ha

One thing needs to be said about resistors, once you put enough power through them to dis-colour the bands (which they normally

have done when repair is necessary), that is what you have.

You need to de-solder them and test them, if they aren't actually screwed.