Amplifier Repair

[slipperybidness]

Yes, class D does have a built in complexity. However I have a huge beef adding the complexity of regulated power supplies to linear designs.

It is true they eek out a small amount of power from the same power amp if you uses a regulated power supply, versus an unregulated one. I personally prefer unregulated power supplies for power amps, for lots of reasons.

The literature that I read specifically says "unregulated linear power supplies are best for power amplifiers". They go on to list their reasoning and arguments as to why this is true.

 

[slipperybidness]

I got very little useful to add, but I will add it anyhow (sue me).
5 years ago my Pana Plasma TV broke. I basically followed youtube guides on trying to find a circuit with a short using nothing but the most basic dollar store multimeter.
After finding the board in question I used these guys to do replace actual chips (surface mounted)

Contact Us - Coppell TV Repair LLC

Component level repairs for main boards, power supply boards, sustain boards etc. for LCD,plasma,LED,OLED TVs by LG,Samsung,Vizio,Insignia,Panasonic,Toshiba,Hitachi etc.

www.coppelltvrepair.com

Replacing regular (non-SMT) components should pretty easy with a moderately cheap setup.
A decent multimeter is $40-50. PC based scope about $100
a Hakko or Weller Digital Soldering station - another $100
but look at this way: 2-3 repairs and you'd be ahead

Agreed, everyone is this hobby should have at least a DMM and a soldering iron! Note--I actually have the analog weller soldering iron. I don't even remember why I went analog vs. digital it has been so long ago, but certainly that was a decision that I made based on my research at the time, I think analog is a little cheaper too.

In fact, everyone should at least have a DMM, period!

I have always been a little leery of the PC based O-scopes. It may be a completely unrealistic fear, but I sure hope those things have some good PC protection circuits built in! It would suck to kill your PC by being careless.

The nice thing about this type of gear is that the people that buy it and use it also tend to take good care of it! Literally taking care of electronics is their job, and these are tools for the job. So, I have picked up excellent condition, good priced, used O-scope, benchtop PS, and function generator. I have a cheap DMM in the truck, a nice auto-ranging true RMS Fluke DMM, then an off-brand DMM that specifically has capacitance/inductance measurement capabilities. That set of tools will get you through "most" electronics work!

EDIT--Also, keep an eye out for when the local electronics schools upgrade their gear and clear out the old gear at auction or at surplus sales.

 

[fuzz092888]

What amps are you talking about? A really major issue, is whether the circuit and service manual are published. If not, only the manufacturer can repair it.
In times passed these items were readily available. Now they seldom are, which is a disgrace. If you post what you want repaired, I can do a search and tell you your prospects. I do repair amps, in fact I repaired a Quad 405 last week.

My prospects for one are good and terrible for the other one. One is an Adcom 7807 and I got a couple repair places from the Adcom website to respond, so there might be hope.

The other is a Verastarr 6.4SE, which is basically a Cinepro, but the OEM for both is/was AB International who seem to be out of business. 4 of the 6 channels seem to be functioning, 2 channels per board, 3 boards. So something on one of the boards must have gone bad.