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Started By
Message
anyone do PCB repair?
Posted on 1/29/17 at 10:12 pm
Posted on 1/29/17 at 10:12 pm
I'm in the appliance trade and printed circuit boards are the norm now. Yet they are so expensive for the customer. I do get a mark-up on them, but I hate hate charging for a $300 board when a relay is all that is wrong.
So I have been teaching myself basic PCB repair.
I was wondering if anyone had suggestions for resources and specialty tools. (I have four different soldering irons and one gun, two of the irons are adjustable)
I can solder well but I don't have things like heatsinks or on board relay testers.
Generally when a board is bad it is 80% of the time a relay 15% a capacitor and 4% the contact pad and 1% other.
What spurred me to really start getting into this, is I had a customer friday. She is in a nice house, nice fridge, i didn't flinch when I gave her the $400 estimate. ($65 less than Bluebook) She brok out in tears. Mother dying of cancer, husband had recently died in a military accident. I felt so bad. I sat there working on her kitchen counter, testing the relays until I found a bad one. Went to my van, grabbed a hold board: I hold all exchanged control boards for 30 days, in case a customer has an issue requiring me to return their money and the new board for credit, then I have to give old board (there is a core charge of $60 on each one). I took a matching relay off the hold board, swapped it with her bad relay and voila her board worked. I charged her pure labor and saved her hundreds.
I actually make more this way and I wouldn't mind trying to be the local guy that does this service. As I like most other companies send boards off to Illinois or California for repair if i can't buy new. (most boards for machines made before 2003 can't be found)
So again. looking for a point to resources, guides, online classes. I feel strong I can do it now, but I like extended personal training because you learn better from multiple people in similar fields.
So I have been teaching myself basic PCB repair.
I was wondering if anyone had suggestions for resources and specialty tools. (I have four different soldering irons and one gun, two of the irons are adjustable)
I can solder well but I don't have things like heatsinks or on board relay testers.
Generally when a board is bad it is 80% of the time a relay 15% a capacitor and 4% the contact pad and 1% other.
What spurred me to really start getting into this, is I had a customer friday. She is in a nice house, nice fridge, i didn't flinch when I gave her the $400 estimate. ($65 less than Bluebook) She brok out in tears. Mother dying of cancer, husband had recently died in a military accident. I felt so bad. I sat there working on her kitchen counter, testing the relays until I found a bad one. Went to my van, grabbed a hold board: I hold all exchanged control boards for 30 days, in case a customer has an issue requiring me to return their money and the new board for credit, then I have to give old board (there is a core charge of $60 on each one). I took a matching relay off the hold board, swapped it with her bad relay and voila her board worked. I charged her pure labor and saved her hundreds.
I actually make more this way and I wouldn't mind trying to be the local guy that does this service. As I like most other companies send boards off to Illinois or California for repair if i can't buy new. (most boards for machines made before 2003 can't be found)
So again. looking for a point to resources, guides, online classes. I feel strong I can do it now, but I like extended personal training because you learn better from multiple people in similar fields.
4
Posted on 1/29/17 at 10:58 pm to Napoleon
Honestly, you are a true American hero 
Posted on 1/29/17 at 11:21 pm to Napoleon
I do...I work on them for my Lionel trains and my audio gear. I am also currently building a power amp from scratch.
I can replace caps, resistors, relays, tube sockets and such, and have soldering irons, torches, and a couple multimeters.
I know enough to get my stuff repaired and working again.
I can replace caps, resistors, relays, tube sockets and such, and have soldering irons, torches, and a couple multimeters.
I know enough to get my stuff repaired and working again.
Posted on 1/30/17 at 7:25 am to Napoleon
I know enough to get me in trouble. Enough to fix my own stuff, but not confident enough to fix someone else's.
Learned a ton of troubleshooting in the military, but there we transitioned to card replacement. So kind of did a memory dump, because half the work was gone.
Learned a ton of troubleshooting in the military, but there we transitioned to card replacement. So kind of did a memory dump, because half the work was gone.
Posted on 1/30/17 at 1:45 pm to kengel2
I got a great example today I can post up.
Lady has a high end oven. I go last week and diagnose from the control. I look for Ohms between the contacts going to the elements. The wiring diagram gives you watts, so you use Ohm's law to figure out resistance. You measure for Ohms and check ranges. Well blatantly I got an open line reading on the bake element. I pulled it and replaced it.
I test it and it works fine.
Lady calls me back frantically Saturday. "IT'S NOT WORKING AND I PAID $366 FOR THE REPAIR!!!"
I go out first thing today and with the board out everything works. Put it back together it doesn't work, pull it back out and it works. Funny. Obvious loose connection somewhere
So I remove the board and find a tiny little partially blown resistor, one leg of it is loose and only completes its circuit when gravity is assisting it. For some reason it makes contact when the board is facing up but when the board is sideways and installed in the oven it does not do it's job.
The resistor goes to the cut-off relay, so with the resistor not making contact the main relay does not allow power pass through.
I usually test with the control open so I can get my plugs in there. It ran great when I tested it, after re-install it failed.
So I took the board home with me and plan on repairing it tonight. The board would have cost here $320 just for the part, and she for sure needed the expensive hidden style element I replaced as it was blown. So it would have been a $600 repair for her.
Because of circumstances I'm not going to charge for the repair on the board.
It's a $0.10 part that I have tons of at home.
Her original complaint was that "nothing happened" when she turned it on. She guessed it was the board, and she was right. But the element had a huge burnt out spot. Looks like the two issues were related. My repair guide says to change both the element and the control and charge $727.85 for the repair. That is crazy.
I did err when I found the bad element and assumed that is all that was wrong.
Lady has a high end oven. I go last week and diagnose from the control. I look for Ohms between the contacts going to the elements. The wiring diagram gives you watts, so you use Ohm's law to figure out resistance. You measure for Ohms and check ranges. Well blatantly I got an open line reading on the bake element. I pulled it and replaced it.
I test it and it works fine.
Lady calls me back frantically Saturday. "IT'S NOT WORKING AND I PAID $366 FOR THE REPAIR!!!"
I go out first thing today and with the board out everything works. Put it back together it doesn't work, pull it back out and it works. Funny. Obvious loose connection somewhere
So I remove the board and find a tiny little partially blown resistor, one leg of it is loose and only completes its circuit when gravity is assisting it. For some reason it makes contact when the board is facing up but when the board is sideways and installed in the oven it does not do it's job.
The resistor goes to the cut-off relay, so with the resistor not making contact the main relay does not allow power pass through.
I usually test with the control open so I can get my plugs in there. It ran great when I tested it, after re-install it failed.
So I took the board home with me and plan on repairing it tonight. The board would have cost here $320 just for the part, and she for sure needed the expensive hidden style element I replaced as it was blown. So it would have been a $600 repair for her.
Because of circumstances I'm not going to charge for the repair on the board.
It's a $0.10 part that I have tons of at home.
Her original complaint was that "nothing happened" when she turned it on. She guessed it was the board, and she was right. But the element had a huge burnt out spot. Looks like the two issues were related. My repair guide says to change both the element and the control and charge $727.85 for the repair. That is crazy.
I did err when I found the bad element and assumed that is all that was wrong.
This post was edited on 1/30/17 at 1:48 pm
Posted on 1/30/17 at 6:18 pm to Napoleon
2 minutes and a spot solder should fix that
Posted on 1/30/17 at 6:22 pm to kengel2
quote:
but there we transitioned to card replacement
Yep--kinda the norm now. I repair them in stuff where I can't get exact replacements or the time to get a replacement is long...but if a new board is $150 or less--it's plug and play---not worth the time and effort to diagnose and repair (it is mentally taxing if I can't find where it is bad!!).
Posted on 1/30/17 at 6:39 pm to Napoleon
Cheap-arse ^h^h^h frugal radio station owners require us to keep 50 year old junk running "just one more time", so PCB repair skills are a must.
A vacuum desoldering station like this bad boy will make your work E-Z. Pro-tip: find one with a foot-switch for the vacuum pump.
A vacuum desoldering station like this bad boy will make your work E-Z. Pro-tip: find one with a foot-switch for the vacuum pump.
Posted on 1/30/17 at 8:42 pm to Napoleon
Good on you Napoleon! Seem like an honest dude willing to help. You service the Raceland Area?
Posted on 1/31/17 at 11:48 am to CHEDBALLZ
I got the board fixed. The resistor that was blow was reading open and then reading like 200 ohms if you put pressure on it. Yet the solder was tight. Odd.
I couldn't see the bands on the resistor so I did research and zoomed in on a picture of the board and saw a red, red, brown, black, brown resistor, or 221 ohms with 1% tolerance.
I had none of those, but I have tons of 220 ohm (red, red, black, black, brown) so since the tolerance is 1% I have 2.2 ohms in either direction to play with a 220 would be fine.
I put it back together and tested the relay using 8 AA batteries, and it works. I have not hooked the board back up to the oven yet. Going to LaPlace to do that now.
--(though with how this lady just talked to me on the phone I wish I just told her to buy a new board and made my extra $100,
)
I couldn't see the bands on the resistor so I did research and zoomed in on a picture of the board and saw a red, red, brown, black, brown resistor, or 221 ohms with 1% tolerance.
I had none of those, but I have tons of 220 ohm (red, red, black, black, brown) so since the tolerance is 1% I have 2.2 ohms in either direction to play with a 220 would be fine.
I put it back together and tested the relay using 8 AA batteries, and it works. I have not hooked the board back up to the oven yet. Going to LaPlace to do that now.
--(though with how this lady just talked to me on the phone I wish I just told her to buy a new board and made my extra $100,
) Posted on 1/31/17 at 11:49 am to CHEDBALLZ
My cut-off is Paradis, but I have made exceptions before.
Posted on 1/31/17 at 1:17 pm to Napoleon
quote:
(though with how this lady just talked to me on the phone I wish I just told her to buy a new board and made my extra $100,
While I applaud your willingness to learn a new thing and genuinely help people at a reasonable cost - I feel like it wont be long before you realize why PCB repair is a dead art on a small shop level.
Posted on 1/31/17 at 3:39 pm to jcole4lsu
Bingo. One of the problems you'll run into is that you might find a bad component but you might not be finding the root cause of the component failure. Replacing the whole board insures all components are fixed. Your customer isn't going to appreciate savings if they have to keep calling you back.
If you know for certain the root cause, then component replacement makes sense.
I love to fix my own stuff but hate messing with other people's stuff.
Someone showed you a resoldering gun. Another cheaper and more portable option is the Hakko Fr-300
I'm afraid you are going to go down the path of no good deed goes unpunished here.
If you know for certain the root cause, then component replacement makes sense.
I love to fix my own stuff but hate messing with other people's stuff.
Someone showed you a resoldering gun. Another cheaper and more portable option is the Hakko Fr-300
I'm afraid you are going to go down the path of no good deed goes unpunished here.
Posted on 1/31/17 at 3:49 pm to DoctorTechnical
quote:until you've owned one you really never know how much you need one. I have that exact model and it's a life saver.Also a goof bench magnifier is a must as well. Proper soldier is also a must.
A vacuum desoldering station like this bad boy will make your work E-Z. Pro-tip: find one with a foot-switch for the vacuum pump.
Posted on 1/31/17 at 7:15 pm to jcole4lsu
yeah, especially since the resitor popped right when it went back on the board.
After further testing. I am lost.
I wasted like 3 hours of research and work and finding the resistor in a random box in my shop. Three hours of work labor going there and back.
Would have been cheaper for me to just buy her the board.
She wasn't too upset, it was obvious I tried.
After further testing. I am lost.
I wasted like 3 hours of research and work and finding the resistor in a random box in my shop. Three hours of work labor going there and back.
Would have been cheaper for me to just buy her the board.
She wasn't too upset, it was obvious I tried.
Posted on 1/31/17 at 7:20 pm to CoolHand
yeah, i thought the resistor was blow due to the short on the heating element. The problem I have is so odd, no one I described it to understands it.
I'm going to load the video I made to Youtube.
It is so odd. It works fine when the board is facing up, does not work when the board is on its side.
I lose continuity on both sides of the element when I move the board.
So when testing everything passes, when in place, nothing works.
I'm going to load the video I made to Youtube.
It is so odd. It works fine when the board is facing up, does not work when the board is on its side.
I lose continuity on both sides of the element when I move the board.
So when testing everything passes, when in place, nothing works.
Posted on 1/31/17 at 8:52 pm to Napoleon
Diagnostic video I uploaded.
Trying to save a customer money, always costs you money in the end. FACT.
Still it feels good to try sometimes.
Trying to save a customer money, always costs you money in the end. FACT.
Still it feels good to try sometimes.
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