When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I swapped the capacitors for some 2200 35v max, unfortunately they only had the axial style capacitors, but I made it work. Unfortunately though it still doesn't work.
With an amp this old, I would say all of the caps are suspect. Typical restoration of vintage electronics is to replace all caps.
BTW, how are you testing?
Yeah I was kind of thinking that too but was trying to be optimistic in that only the two mains were gone. I'm using the capacitance feature on my dvom.
All output channels are bad, even with a known good input?
If you're having fun with this, carry on -- but this amp looks pretty simple on the inside, and that leads me to believe you could get a vintage audio restoration shop to restore it for you for a few hundred dollars. The only thing that tends to stop them cold app-specific ICs that aren't available. Discrete components like caps and power amp transistors are typically still available -- and that looks like the case here.
Like many others I find a true thrill in taking something broken and fixing it myself. We live in a throw away society today and most people don't even know how to change the time on their kitchen stove. Next I will swap out the rest of the caps and hopefully give this amp another life to live.
Way.. way.. back when troubleshooting an Amp, I would start with checking the power supply for proper function, then using a signal generator (set at correct voltage and frequency) at the Amps Inputs and Scope the circuit through to the Output Amplifier circuits outputs.
Else you are just a shotgunner, and rule of thumb is always replace both Cap and Resistor in an R/C circuit as they work together.
I'm just speculating, that someone ran a new Head unit (new ones typically output 20 to 25 watts RMS) and they over drove the Inputs of that old Power Amp that has an Output of about 20 watts RMS !!!
End results is smoked components as you have seen, good luck you just might get lucky
So I received the radio I purchased from otr18wheeler and tested it today, works perfectly. Unfortunately it's in rough shape so I have to transplant the good parts into my radio. I can't believe both the radio and amp were fubar. Any tips on what to look for in a no output signal situation? I see there's another capacitor in the rear by the output jacks, maybe that's a good place to start.
I started taking apart the working unit so I can transplant the good part(s) into my unit. Here's what it looks like apart. Last picture shows the piece that I think is the culprit on my unit, so I'll swap that in first and see if it does the trick.
End result, radio and cassette works perfectly. It turns out the section of radio that holds the volume control and rear output connections was faulty, I will probe/troubleshoot it at a later time in hopes of salvaging the radio and getting it to someone who needs an OEM period correct piece in their car. I swapped in the unit from the donor radio and everything works great. Thanks to everyone who helped with parts and suggestions.
I replaced all of the capacitors and a few resistors in the amp, but still no luck. Thankfully I was able to buy an identical radio that was beat up but working and swapped in the necessary parts needed. Seems like there was some kind of overload issue that blew the amp and part of the radio itself.
03-28-2016, 02:12 AM
