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Elenco AM/FM-108ck Radio kit build. Failed Output Bias Test

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I've just started building this kit and already have an issue with the output bias test.

9v battery at time of testing measured 8.57v

Static Measurements -
- Power Test measured 3.60 milliamps. Manual says current should be less than 10.
- Output Bias Test only measures 0.67volts Between TP1 & TP15.
  Manual says it should read between 3 to 6 volts.
  Note; Turn power off and voltage reads 1.36v and continues to drop.

I have
- Double checked all resister values
- Checked capacitor values and pos / neg orientation
- Re flowed / soldered all joins
- Double checked orientation of IC is relevant to notch shown on PCB

Only thing different I have done is used slightly thicker gauge wire at the speaker / earphone jack.
Two pics attached.
More pics here https://mega.nz/folder/QpknjYyI#dAxlw08nsooE-6IJXjftMw

Happy to add further pics of schematics / manual etc

Appreciate your time and thanks for checking this post out.

Guessing that IC is an LM380.
Possibly C40 is bad, allowing leakage current into the IC input.

Thanks for your reply Circlotron

The IC is marked LM386N, SUM 14L01S.
I checked C40 while still attached to board with a basic ESR meter and it read 0.608
I will de solder tomorrow and check again.
C40 is 10uf 25v


I have replaced battery with a new 9v that measured 9.94 volts out of the box.
Repeated the power test as described in the manual, powered on and found there was a vibrating sound coming from the speaker and milli amps seemed to climb and thus turned it off.
Repeated the test with the earphone connected and the noise seemed more noticeable (amplified?) and again amps continued to rise.
I have gone back over all connections for shorts etc and checked continuity and all seems as it should.

U1 LM386 pin 5/TP1 is ideally around 1/2 battery voltage (bias) at idle. But hard to measure if it is oscillating or motorboating, the multimter reading will be wrong with all that AC voltage there.
Did you solder the 0.1uF cap C45 correctly on the bottom side of the PC board, across pins 2 and 6, it's mirror-imaged the pin count. Same for C39 470uF. These caps are essential to keep the LM386 from going unstable.
What does the volume control do?

edit: I looked at your assembly pics and it looks fine, I think your soldering is a bit cool meaning leave the tip touching the PCB an extra 2 seconds to transfer heat to the PCB. The solder is not flowing and making a good fillet, which can lead to bad connections.


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