Finished assembling the amp, LEDs light up both channel, I was able to set the DC balance, but extremely low output from the right. My knowledge of electronics is very limited, this is the 3rd amp kit ( Hafler and Akitika) I have built and the others work fine. I checked the back side of the board and can`t find any cold joints or solder bridges. If anyone has time to look at the pics and advise me, I would be grateful. I`m hoping it is something simple. Thanks.
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Transistor or electrolytic in wrong way around ?
I had a pig of an amp to fix once.
It played but distorted. I checked every component on the pcb and all checked fine.
But I kept coming back to one transistor where voltages seemed wrong.
SO diode checked it and ok but then I realised it was checking backwards.
Some kind person got i nbefore me and put in a pnp instead of an npn transistor.
The transistor had lost its markings so that was no help.
So replaced wrong transistor and it burst inti life sounding great.
I had a pig of an amp to fix once.
It played but distorted. I checked every component on the pcb and all checked fine.
But I kept coming back to one transistor where voltages seemed wrong.
SO diode checked it and ok but then I realised it was checking backwards.
Some kind person got i nbefore me and put in a pnp instead of an npn transistor.
The transistor had lost its markings so that was no help.
So replaced wrong transistor and it burst inti life sounding great.
get input signal directly to pcb, to deduce is it to pcb itself or input wiring harness
desolder existing input wires prior to that
desolder existing input wires prior to that
You've got some solder joints that look suspect. Also, check all your resistor values against this Resistor Color Code Calculator.
If you have one channel working, you are in luck, it will be much easier to troubleshoot the problem in right channel. Simply measure all important voltages on both channels, write it into schematics, blue for left channel, red for right channel. Post.
Good point! Step 56 “Troubleshooting” in the Amp Camp V1.6 build guide gives voltage and resistance labeled pictures.
Thanks for all the advice. I plan to work on it some more Wed. I thought that I might have twisted the input wires to tight and broke one in the process.Thanks again everybody for all the help.
If input wires are the issue, testing continuity or for shorts with an ohmmeter is a quick and easy job 🙂
So far I have replaced input wires and resoldered the board, and performed the trouble shooting per the build guide. Everything checks out and is in the range on both boards. Still very low to no output on the right side. Also I removed the board and checked to see if any wires that were soldered from the front were to long. Any more advice is appreciated.
It's got to be input or output wiring then. Are the RCA and binding posts isolated from the chassis? If you've built other amps before you have probably noticed that the washers have an orientation...check that they're correct. You can beep them out (continuity test) to find out.
To try to isolate the problem unsolder the left channel and right channel output wires from the amplifier boards and swap them. Still weak output from the right channel speaker jacks? If yes, then it is the right channel output wiring that is the issue. If no, then the problem is with the right channel board or the input into the right channel board.
Today I switched input and output wiring from left channel to right. Both boards are working, so I switched input terminals from left to right, and it is not the input. I disassembled and resoldered the output terminals and carefully reassembled it with the same result, very little and very distorted output from the right side. Any more suggestions ? I am at a loss now.
"Both boards are working" - what do you mean by that?
I had suggested you switch the output only so that it can be determined whether the fault was with the output wiring. But you switched both the input and output. Did you then get weak output from the left channel speaker output?
I had suggested you switch the output only so that it can be determined whether the fault was with the output wiring. But you switched both the input and output. Did you then get weak output from the left channel speaker output?
You keep inputs switched, because thats how it works, and listen upside down. While doing headstand.
Verify before doing anything else that yes, both channels have identical voltage readings as shown on step 56 of the ACA 1.6 guide.
https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.6+Build+Guide/5?lang=en
https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.6+Build+Guide/5?lang=en