Marantz PM 310 low volume

[rayma]

QN03.......I do not find....

It's there on the same board, connected to RN04 and RN05.

 

[Lynyrd]

But QN03 I do not find

 

[Lynyrd]

https://zupimages.net/up/21/48/w4p6.jpg

 

[rayma]

I can't see much on the photo.

See if you can find those resistors, and trace back to the diode.
Or just measure at the common end of the two resistors, to ground.
That will be good enough for now.

The J801 wire eyelet is connected to the anode of that diode.

 

[Lynyrd]

No..... nothing....no J801.

+33v on RN04 other side 0v.


+33v on RN05 other side 8.2v

 

[rayma]

Ok, that's good enough.

Can you measure the DC voltage to ground at each end of resistor RN03?
One end should be 32V, the other end is in question.

 

[Lynyrd]

34.3v other side 0.9v

 

[Lynyrd]

QN04 dead, desoldered and tested with my parts tester.

 

[Lynyrd]

QN04 replaced,no results

 

[rayma]

Ok, keep checking transistors and diodes. If no more are bad,
then check the resistor values.

 

[Lynyrd]

QN1 &. QN2 also deads.
After replacing Amplifier works fine.
Thank you very very much

 

[Lynyrd]

Loudness knob works fine

 

[rayma]

QN1 &. QN2 also deads.
After replacing Amplifier works fine.
Thank you very very much

Good work. I was wondering if some of the capacitors were shorted,
but for some reason several transistors were bad instead.
That's kind of unusual.

 

[Lynyrd]

No suspect parts. ...

 

[Lynyrd]

Can I ask you one question?
I have a Pioneer TX 205L FM tuner.
The power transformer is dead.
No service manual......
What voltage on secondary for stereo FM tuners?
Thanks

 

[Lynyrd]

15v?

 

[rayma]

That's not something you cannot guess at, so look for the schematic.
I don't know what the L means.
PIONEER TX-520 SERVICE MANUAL Pdf | ManualsLib

That manual's version needs 16.5VDC, but it uses a voltage doubler, so the secondary winding
is likely to be around 6.3VAC. I wouldn't be surprised if all the tuner versions had the same voltage
of secondary winding.

 

[Lynyrd]

Ok, thank you.