Biggles Posted March 3, 2023 Report Share Posted March 3, 2023 Hive Wisdom Sought. This is the circuit board from a Dometic RMD8555 3 way fridge. The fridge packed up and I got to hear of a company called Get It Fixed. I contacted them and they said they had experience of this board and on sending it in the diagnosed this chip needed replacing. I paid and a couple of weeks later its arrived back. I'm not an expert in electronics. This chip looks exactly the same as before and there seems to ne no evidence that the chip has been changed. I have seen these changed on YouTube and a heat gun is used to do the soldering, but there is no evidence either on the front or the back of the board to suggest its been changed. Before I remount the board I wanted opinion, as I suspect they have done nothing and will go on to say I have damaged the board when connecting it up. Thoughts please Link to comment Share on other sites More sharing options...
robtheplod Posted March 3, 2023 Report Share Posted March 3, 2023 I suspect you're going to have to fit it to see if works aren't you? No point having a go at them if they have repaired it ok? Link to comment Share on other sites More sharing options...
Biggles Posted March 3, 2023 Author Report Share Posted March 3, 2023 Yes I get that, but a little expert comment would be valuable. Do you have anything from an expert POV to say? Link to comment Share on other sites More sharing options...
alan_fincher Posted March 3, 2023 Report Share Posted March 3, 2023 I'm not up to speed on modern day repairs of PCBs, but did used for a while to do it as a day job back in the mid 1970s. I find it hard to believe that that chip has been manually de-soldered, removed and replaced to show so little evidence of such an operation. There is no evidence of flux left around, for example. Is it possible that what they have actually done is to simply send you a complete board that they held in stock? Can you conclusively say that the board you have got is the one you sent them. 1 Link to comment Share on other sites More sharing options...
jake_crew Posted March 3, 2023 Report Share Posted March 3, 2023 FWIW the close up of the chip shows untidy soldering to me. So perhaps they have done something. 1 Link to comment Share on other sites More sharing options...
MtB Posted March 3, 2023 Report Share Posted March 3, 2023 Once it arrived, they may have traced the fault to something else and fixed that instead. Or… Are you certain this is the board you sent them? They might well have sent u a different, repaired board. Link to comment Share on other sites More sharing options...
IanD Posted March 3, 2023 Report Share Posted March 3, 2023 (edited) That does look like a chip that's been manually (re)soldered to me, but it's difficult to be sure. There's normally no added flux used when reworking a QFP (Quad Flat Pack) package like this, it drops onto the solder already on the PCB pads. Edited March 3, 2023 by IanD Link to comment Share on other sites More sharing options...
robtheplod Posted March 3, 2023 Report Share Posted March 3, 2023 1 hour ago, Biggles said: Yes I get that, but a little expert comment would be valuable. Do you have anything from an expert POV to say? oops sorry no, I'm not an expert.... Link to comment Share on other sites More sharing options...
GUMPY Posted March 3, 2023 Report Share Posted March 3, 2023 Soldering if redone properly can't be seen by an amateur to have been done. It may also not be your original board but an exchange board they will then fix yours at leisure and someone else will get it Fit it and find out if it works😱 Link to comment Share on other sites More sharing options...
Higgs Posted March 3, 2023 Report Share Posted March 3, 2023 1 hour ago, Biggles said: Yes I get that, but a little expert comment would be valuable. Do you have anything from an expert POV to say? There maybe nothing wrong with the chip, and may have been put in an oven to reflow the solder. It may have had a few dry joints. It can also be done with an hot air gun. Link to comment Share on other sites More sharing options...
cuthound Posted March 3, 2023 Report Share Posted March 3, 2023 I visited the Deep Sea factory once. On their repair line they put PCB's into an oven and used a vacuum to remove the solder, before replacing any faulty components and dipping the lower part of the board into a bath of molten solder. This left no evidence of a manual repair. Link to comment Share on other sites More sharing options...
IanD Posted March 3, 2023 Report Share Posted March 3, 2023 18 minutes ago, cuthound said: I visited the Deep Sea factory once. On their repair line they put PCB's into an oven and used a vacuum to remove the solder, before replacing any faulty components and dipping the lower part of the board into a bath of molten solder. This left no evidence of a manual repair. This can be done sometimes if all the components on the PCB can be reflowed, but often a finished PCB has had other things added in final assembly which don't allow this. Reworking a small QFP like this is actually quite easy to do by hand given the right tools, without disturbing anything else on the PCB. A BGA (Ball Grid Array) with >1000 pins is rather more difficult, but can still be done if you *really* know what you're doing... 😉 Link to comment Share on other sites More sharing options...
Bee Posted March 3, 2023 Report Share Posted March 3, 2023 You should have let me have a go at it - you'd soon see the difference. 1 Link to comment Share on other sites More sharing options...
Jen-in-Wellies Posted March 4, 2023 Report Share Posted March 4, 2023 I have been involved with this sort of repair more recently. A skilled person can replace a component like that and leave no evidence that it has been done. That you can't tell, either shows they haven't done it, or they have done it and are very good at their job. See if it works! 1 Link to comment Share on other sites More sharing options...
MtB Posted March 4, 2023 Report Share Posted March 4, 2023 31 minutes ago, Jen-in-Wellies said: I have been involved with this sort of repair more recently. A skilled person can replace a component like that and leave no evidence that it has been done. That you can't tell, either shows they haven't done it, or they have done it and are very good at their job. See if it works! If I'd done it using my old Antex smouldering iron there would be plenty of evidence it had been done, AND it probably still wouldn't work... 1 Link to comment Share on other sites More sharing options...
GUMPY Posted March 4, 2023 Report Share Posted March 4, 2023 15 minutes ago, MtB said: If I'd done it using my old Antex smouldering iron there would be plenty of evidence it had been done, AND it probably still wouldn't work... You would have used an Antex and not a blow torch ? Link to comment Share on other sites More sharing options...
MtB Posted March 4, 2023 Report Share Posted March 4, 2023 25 minutes ago, Loddon said: You would have used an Antex and not a blow torch ? I'd warm it up with the blowtorch, obviously. Link to comment Share on other sites More sharing options...
magnetman Posted March 4, 2023 Report Share Posted March 4, 2023 perhaps worth applying some sort of indelible invisible mark somewhere to identify the board. Drill a very tiny hole somewhere or something. Are they reserving the right to send you an exchange or are you paying for a repair to your own board? Link to comment Share on other sites More sharing options...
GUMPY Posted March 4, 2023 Report Share Posted March 4, 2023 28 minutes ago, magnetman said: perhaps worth applying some sort of indelible invisible mark somewhere to identify the board. Drill a very tiny hole somewhere or something. Are they reserving the right to send you an exchange or are you paying for a repair to your own board? I wouldn't care so long as the board worked🥴 2 Link to comment Share on other sites More sharing options...
blackrose Posted March 4, 2023 Report Share Posted March 4, 2023 22 hours ago, Loddon said: Fit it and find out if it works Yes, and if it works then this thread was unnecessary. I can't see the point of all the speculation - just get on with it and fit the board. If it doesn't work then there's a different conversation to have with the repairer 1 Link to comment Share on other sites More sharing options...
booke23 Posted March 4, 2023 Report Share Posted March 4, 2023 (edited) On 03/03/2023 at 15:00, Biggles said: Hive Wisdom Sought. This is the circuit board from a Dometic RMD8555 3 way fridge. The fridge packed up and I got to hear of a company called Get It Fixed. I contacted them and they said they had experience of this board and on sending it in the diagnosed this chip needed replacing. I paid and a couple of weeks later its arrived back. I'm not an expert in electronics. This chip looks exactly the same as before and there seems to ne no evidence that the chip has been changed. I have seen these changed on YouTube and a heat gun is used to do the soldering, but there is no evidence either on the front or the back of the board to suggest its been changed. Before I remount the board I wanted opinion, as I suspect they have done nothing and will go on to say I have damaged the board when connecting it up. Thoughts please In the distant past I used to work in electronics manufacture and I spent a bit of time in the faults and rework department.......where this sort of repair (and much more complex BGA repairs) would be undertaken on boards that had just come off the line, which for whatever reason, would occasionally need remedial work. I agree with what others have said.....ie done properly with the correct equipment you cannot spot this sort of repair. On the left side of the chip a few of the legs show signs of rough but probably perfectly functional soldering. I think you need to plug it in. Edited March 4, 2023 by booke23 Link to comment Share on other sites More sharing options...
Onewheeler Posted March 4, 2023 Report Share Posted March 4, 2023 Looks like a solder bridge (or spatter) top left of lower picture. Doesn't look original anyway. 1 Link to comment Share on other sites More sharing options...
StephenA Posted March 4, 2023 Report Share Posted March 4, 2023 Re flowing the solder (usually fluxless) on QFPs is pretty common practice... Just about anyone with a turn of the Millennia Volvo (S60 etc) has had this done on their dash module at least once, and there is no sign on the reflowed boards that anything has been done. Link to comment Share on other sites More sharing options...
magnetman Posted March 4, 2023 Report Share Posted March 4, 2023 59 minutes ago, Onewheeler said: Looks like a solder bridge (or spatter) top left of lower picture. Doesn't look original anyway. I don't do any of this sort of thing but first impression was that this looked a bit naughty Link to comment Share on other sites More sharing options...
robtheplod Posted March 4, 2023 Report Share Posted March 4, 2023 7 hours ago, Jen-in-Wellies said: I have been involved with this sort of repair more recently. A skilled person can replace a component like that and leave no evidence that it has been done. That you can't tell, either shows they haven't done it, or they have done it and are very good at their job. See if it works! Ah, vindicated, thanks Jen! Link to comment Share on other sites More sharing options...
Featured Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now