Luxman L-11 integrated amp...

[Tim Schwartz]

Hello all,

I\'m working on an L-11 which has issues with the -b2 power supply which
feeds the front end of both channels of power amp. While I have a good,
clear downloaded schematic, it does not have any voltages on it. Any
chance that someone here has a factory service manual that you\'d be
willing to lend, or at least tell me about some of the voltages on the
schematic?

Thanks!
Tim Schwartz
Bristol Electronics

 

[jurb...@gmail.com]

Not hard. Look at the -B2 regulator circuit. The reference which is direct is two Zeners, WZ-270. In series they add up to 54 volts. That will approximately be the regulated output.

 

[Tim Schwartz]

On 12/25/2020 1:06 PM, jurb...@gmail.com wrote:

Not hard. Look at the -B2 regulator circuit. The reference which is direct is two Zeners, WZ-270. In series they add up to 54 volts. That will approximately be the regulated output.

Hi there,


I\'d agree, but the diodes are buring up hot, and I\'m using 1 watt in
place of the half watters. Several of the resistors have been replaced
before, and I\'m wondering if there is an error in the schematic as to
the part value. I\'ve replaced the pass transistor and dual diode as well.

Thanks!
Tim

 

[Phil Allison]

Tim Schwartz wrote:

I\'d agree, but the diodes are buring up hot, and I\'m using 1 watt in
place of the half watters. Several of the resistors have been replaced
before, and I\'m wondering if there is an error in the schematic as to
the part value. I\'ve replaced the pass transistor and dual diode as well.

** Try changing that 15 ohm in series with the PNP transistor to 27 or 33 ohms.
The circuit is a *current source* of about 45mA.
The load current is only about 12 mA leaving a lot for the two 27V zeners to cop.



...... Phil