 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
76.167.189.8
I recently had my amp in a shop to be checked for a problem it is having, the tech checked out for a nominal fee and said he was pretty sure it was a cold solder joint some where on the output board, voltage regulator section ? Anyway they wanted $200 + to find and repair it. Is there an easy way to track down a cold solder joint ? I can solder just fine and I have a soldering iron plenty of solder a Digital multimeter and I have a very powerful magnifying glass I used to use to get fine metal slivers out of me when I did bodywork . and I know what a cold joint is, other than that, just free time on my hands all day tomorrow. Any help or ideas would be great !
Follow Ups:
than a good joint. They also may have a pit or divot as compared to a clean joint that does not, a good joint has that "volcano" look. You can just resolder all the joints. You need a good iron not any old iron and I would use a high temp and keep the time on each joint and the added solder to a minimum. Good luck.
ET
Your problem sounds a lot like there is a protection circuit detecting DC at one of the outputs and is (un)powering a relay to protect your speakers. If it is the case, it should be simple to narrow the problem down to the defective channel. Use your multimeter to measure both outputs, before the relay contacts, while it is doing the problem and confirm if there is DC on one or both of them or not. You said both meters peg to full and that leads me to believe the problem could even be in the power supply section as it looks like it affects both channels at the same time. I don't know the amplifier in question so I could be way of track here.
As Tweekeng said, it is a good idea to poke at components to try to recreate the problem at will. To resolder all the joints is not a bad thing but you will learn nothing this way so personally I would keep this solution as a last resort when all else fail. This is unless you are not interested in the process and all you want is your amp in working condition as fast as possible...
$200?!!? If you can solder, go through and redo each and every solder joint. Shouldn't take more than an hour and since you personally redid each one, you can certainly find out if the armchair diagnosis was correct to begin with.
Is there an easy way to track down a cold solder joint ?
Easy? well.... Yes, no... maybe...
Here is a couple things to look for. Most cold solder joints in power sections are caused by a marginally rated component (over) heating and cooling and are accompanied by darkening of the PCB around the solder joint.
If you are brave you can run the amp open and poke at components with a plastic stick and listen for changes, crackling, etc...
You haven't given us any symptoms to go on, it could be something simple like a dirty switch contact or even a component failing.
Sorry I left out that info, its an SAE Two A-14 integrated amp 140 wpc at 8 ohms 25+ years old . I just got a copy yesterday of the service manual from jim's SAE site . He seems to have info of most SAE stuff. Symptoms are a pretty loud pop sound then the power meters peg to full. It sits for a while then just comes back one running fine, it doesn't get hot when they are pegged just no sound whatsoever, also if you tap the case on the top like when I was trying to get an album to go back into a stubborn cover it pops and comes back on playing just fine. Last, if I leave it on all day it might do it once in a great while but everything sounds just fine when it's functioning.The only thing else I can say is that it did it the 1st time when I was running some MMG's, it didn't do anything to the speakers fuse was fine and when it popped back on everything ran fine. I have it hooked up for while I am checking it out to a pair of Tritrix Parts Express speakers I built for my daughter, it has done what I described many times to these and nothing seems affected at all. If the tweeter go it's almost nothing to replace so they are kind of my test subjects while I see if I can repair this or search for another person when can that wont cost more than the amp is worth.
Freeze spray on suspect contacts is a good way to find the problem.
Either it does or it doesn't. I think it's kind of arbitrary that he tells you that, unless he already knows something about your particular amp. Have you checked with the manufacturer first? You could easily touch up most or all of the solder joints without worrying about it, if you know how to solder well. First thing though, would be to do a thorough visual inspection. But I'd rather go about diagnosing the problem in a more standard fashion. With a schematic/service manual. Get that first if you plan on fixing it yourself. Then you can measure at the voltage points and/or trace the signal path. If you know what the regulated voltage is supposed to be and where to find it, then you are off to a good start.
Seems like a rip off if he only has to redo a solder joint or two and then charges you $200. But you never know what this guy may be up to. Try and find some guy who works out of his garage instead, maybe an older retired guy. You'll still get the same level of service and save yourself a few bucks.
Post a Followup:
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
