Led not lit and no output sound.

[Hilts]

A3 led would not light then I realised that some stray solder had crossed over from A3 to A4. I resoldered the centre pin, A3 and removed the stray solder. The A3 led will still not light, the other led is lit ok.
When I connect my streamer there is no output sound in my headphones. Have I blown the 9 pin socket when A3 and A4 have shorted out ?

 

[Doc B]

In theory a bad LED might kill the output in one channel but it's very unlikely to kill both channels. So there may be more than one issue that needs fixing. What are your voltages? This can help us to determine where the issues may be located.

 

[Hilts]

Resistance Check.

1.  0.630m Ohm
2.  0.606m Ohm
3.  0.2 Ohm
4.  0.480m Ohm
5.  0.530m Ohm

6.  0.3 Ohm
7.  2983 Ohm
8.  0.3 Ohm
9.  2983 Ohm
10. 0.3 Ohm

12. 0.3 Ohm
13. 0.465m Ohm
14. 0.3 Ohm

20. 0.3 Ohm
22. 0.3 Ohm

B3. 2980 Ohm
B6. 2982 Ohm

Center pin.  Black 101.1 Ohm  Red 100.6 Ohm
Ground Tab. Black 0.3 Ohm  Red 0.4 Ohm

Voltage Check

1.  68.9v
2.  180v
3.  0.02v
4.  180v
5.  69.2v

6. 0.02v
7.  102.5v
8.  0.02v
9.  101.4v
10. 0.013v

 

[Doc B]

Regarding no sound, you are missing wires from the center terminals of the volume pot to 12AU7 socket pins A2 and A7. I would fix that first - see page 34/35 of the manual. Regarding the LED, the photo you posted shows a whisker of what looks to be wire or something between A4 and A3. Is that the one you removed?

 

[Hilts]

Thanks Doc. Can't believe I've missed this, school boy error  :-\

I have removed the stray solder between A3 and A4

 

[Hilts]

We have sound and what a sound it is. The missing 2 wires was the problem.... Doh

The led is still not working though. Could it have blown when the stray solder connected between A3 and A4?

 

[Paul Birkeland]

If the LED isn't light up, then your voltages likely aren't correct.  Can you post them?

 

[Hilts]

Which voltages do you need Paul? I posted my voltage check in earlier post on this thread. Are these OK.

 

[Paul Birkeland]

Carefully measure the voltage at A3.

 

[Hilts]

Voltage at A3 is 0.550 VCD and A8 voltage is 1.590 VCD

 

[Paul Birkeland]

What's the resistance between A3 at terminal 3?

 

[Hilts]

Resistance between A3 and terminal 3 is 420 Ohms

 

[Paul Birkeland]

Does it change if you pull the 12AU7 out?

 

[Hilts]

No is still reads 420 Ohms

 

[Paul Birkeland]

If you heat up pin 8 on the power transformer and slip the black wire out, does the DC resistance at A3 change then?

 

[Hilts]

Wire removed from pin 8. Paul do you mean check the resistance between A3 and terminal 3 or do a DC voltage check at A3 ?

 

[Paul Birkeland]

Resistance.

 

[Hilts]

Resistance is still 420 Ohms

 

[Paul Birkeland]

I would replace the 9 pin socket and the LEDs (since they probably won't come off without being damaged).  There's likely debris inside the socket giving partial continuity between pins 4 and 3 causing this problem.

 

[Hilts]

What actually is the function do the led's. Is it just to light up the valve? Would it affect the sound at all as to me the amp sounds amazing.