Herbert: power loss?

[amporo]

Hi,
my amp (Herbert) have power loss.
All the tubes are ok; the bias is around 68mA (-41Volt); the Voltage on the 1K resistance to the power tubes is 485 Volt; no items are burned;
The sound on the clean channel goes distored when I cranked up the volume nobs but the power stays low as an 20 Watt amp!
Have you a suggestion? I'm a tech but not a proffessionel.
Thanks for answering

 

[Peter Diezel]

Welcome to the forum

You will need a tech to check the output transformer

 

[amporo]

Hi Peter,

I measured on the OT (Input, with middle wire lifted up from the board)
left wire to middle wire = 13,8 Ohm / right wire to the middle wire = 20 Ohm.

I hope it could be helpful.

 

[Emg77]

Hi,
my amp (Herbert) have power loss.
All the tubes are ok; the bias is around 68mA (-41Volt); the Voltage on the 1K resistance to the power tubes is 485 Volt; no items are burned;
The sound on the clean channel goes distored when I cranked up the volume nobs but the power stays low as an 20 Watt amp!
Have you a suggestion? I'm a tech but not a proffessionel.
Thanks for answering

I know it may sound silly but are you using active pick ups? Sounds like when the battery goes dead with my emg's. Just a thought

 

[amporo]

Hi,
my amp (Herbert) have power loss.
All the tubes are ok; the bias is around 68mA (-41Volt); the Voltage on the 1K resistance to the power tubes is 485 Volt; no items are burned;
The sound on the clean channel goes distored when I cranked up the volume nobs but the power stays low as an 20 Watt amp!
Have you a suggestion? I'm a tech but not a proffessionel.
Thanks for answering

I know it may sound silly but are you using active pick ups? Sounds like when the battery goes dead with my emg's. Just a thought

@Emg77
I believe that’s not the problem. I think it’s the output transformer.
I checked the output transformer, and the windings of both Input coils has different resistance.
(left wire to middle wire = 13,8 Ohm / right wire to the middle wire = 20 Ohm.)

I wait to see what Peter suggests.

 

[amporo]

Welcome to the forum

You will need a tech to check the output transformer

Hi Peter,

I measured on the OT (Input, with middle wire lifted up from the board)
left wire to middle wire = 13,8 Ohm / right wire to the middle wire = 20 Ohm.

 

[Peter Diezel]

About 36 ohms from the brown to the red wire.
That´s ok but more important would be the
inductivity to check if it´s ok.