Alinco DJ-180 handheld transceiver, low audio output

sghioto

Joined Dec 31, 2017
5,380
That had no effect.
Interesting.
Couple of things to check if you can't get any voltage readings. If you suspect Q16 try bypassing it with a jumper
to get power to the audio IC. Also suspect the output cap C110 and filter cap C108. I have seen problems relating to both caps in my profession.
1650823616732.png
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
Thanks for your help. I'll have to solder a jumper to manually short to ground, as I can only operate the radio with the boards assembled since the audio circuitry is in the middle there.
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
Well, it's not Q16 (UN2214). I put the test voltage of 2.9V on the base and the collector was pulled to ground. I'm still hunting the component layout diagram to find C108 and C110.
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
Are you able to get voltage readings?
It looks like both boards have to be mated in order for the everything to work. The audio circuitry is on the top side of the bottom board. I might be able to probe a couple of points, but not many. See the photo. It may look bigger than it is in the photo...I'll definitely need to make a 90deg probe tip, but getting it in there to the right spot will be quite difficult.

IMAG1414.jpg
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
I watched a Hindu Indonesian video of a DJ-180 repair and one of those caps was identified as the problem. I may just go ahead and replace them, if I can do it. (I was looking on the other side of the board; never thought they would be on the RF side.)
 
Last edited:

Thread Starter

upand_at_them

Joined May 15, 2010
940
The service manual says that C108 and C110 are tantalum ("Chip Tantal ECEV0JA476P"), but they sure look like electrolytic SMD to me. I'm assuming this is a print mistake, as tantalum doesn't even come in a cylindrical can.
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
I'm not sure about the cap markings. See image. The audio output cap (C110) appears to be 100uF/6V instead of the 47uF in the service manual. The filter cap (C108) does appear to be 47uF, but not sure about that voltage rating. Or the tolerance of either one.

IMAG1418.jpg
 

Thread Starter

upand_at_them

Joined May 15, 2010
940
Since I had the back exposed I measured the test voltages at the two caps (C108 and C110) and they both check out. Apparently this is with squelch off, as squelch on had very low voltages.

I'll try to get the other voltage tests, but it's not going to be easy.

Edit: I checked a couple more test voltages. One failed. Pin 7 (bypass) of the 386 amp.

4-20-2022 8-32-14 PM.png
 
Last edited:

Thread Starter

upand_at_them

Joined May 15, 2010
940
I checked the 386 audio amp pin 7 for a third time and it was okay. I must not have been hitting it before. Access is pretty tight.

I probed the pre-amp transistor (Q13)...Seems okay?

I should be able to get to Q15, if I make a long thin probe tip with a short 90deg bend. And *maybe* Q14, but that's a big maybe. Probably not Q16, though.

4-20-2022 8-32-14 PM.png
 
Top