Sansui AU alpha 707MR - Hot?

[pete_mac]

The Bourns multi-turn are available in different styles and orientations. There's a type to suit your exact needs.

 

[missak]

Hi. The new trimpots arrived and I'll start the replacement.

I'm afraid to damage the patterns, so I wanna ask you some help, please. For the job, I even bought a soldering station, YIHUA 937BD+.

1) Which temperature should I choose to work safely and not damage the PCB tracks?

2) Which kind of desoldering wire is recommended for this kind of job? Regular, unfluxed or no clean?

3) Any other tips?

 

[LA3WMA]

Here is what the manual says..

 

[pete_mac]

Here is what the manual says..

Nice one! It's very generous of you to help. Very cool that it also applies to the 607MRX, which I'm fortunate to have here at present.

I'm assuming you only have a hard copy of this document, and not an electronic copy of the schematic etc?

 

[LA3WMA]

I only have the hard copy of this manual.

 

[Hyperion]

Thank you for clearing up the confusion regarding the bias setting figure.

 

[LA3WMA]

I have the 907DR and it is not very hot. It's adjusted to 8,8 mV

 

[missak]

Here is what the manual says..

I have the 907DR and it is not very hot. It's adjusted to 8,8 mV

Then, in 907DR, the Bias current is 40mA (assuming that the emitter resistor is 0.22R).

And accordinhg the service manual (thanks for the pic ), the a707MR Bias current is around 42mA (10mV / 0.235R = 42.55mA).