Electronics

Janne · Guest

Hi,

I have change the output transistors on a Luxman L510 and I need to
set the idling current, anyone know how to do it?

Mark D. Zacharias · Guest

Of course the correct way is to use the method in the service manual.
Lacking that, the remaining good channel is often a usable guide - adjust
the bias for about the same voltage across the emitter resistors. Usually
about 5 to 15 millivolts across each emitter resistor. My old Luxman L430
had you remove a jumper or 2 and actually measure the idle current, but
measuring across those resistors implies the same thing, and doesn't load
the circuit. (Most any DMM on a low-current range will have a certain
resistance value which can kind of screw up the very measurements you're
trying to make)

Mark Z.

"Janne" <jbl@rixtele.com> wrote in message
news:e64b1552.0502102244.48cb5e27@posting.google.com...

Asimov · Guest

"Mark D. Zacharias" bravely wrote to "All" (11 Feb 05 06:00:35)
--- on the heady topic of "Re: Set idling current on a Luxman L510"

MDZ> From: "Mark D. Zacharias" <mzacharias@yis.us>
MDZ> Xref: aeinews sci.electronics.repair:10200

MDZ> Of course the correct way is to use the method in the service manual.
MDZ> Lacking that, the remaining good channel is often a usable guide -
MDZ> adjust the bias for about the same voltage across the emitter
MDZ> resistors. Usually about 5 to 15 millivolts across each emitter
MDZ> resistor. My old Luxman L430 had you remove a jumper or 2 and actually
MDZ> measure the idle current, but measuring across those resistors implies
MDZ> the same thing, and doesn't load the circuit. (Most any DMM on a
MDZ> low-current range will have a certain resistance value which can kind
MDZ> of screw up the very measurements you're trying to make)

Sometimes the inductance of the lead cables can even cause oscillation
in the emitter.

A*s*i*m*o*v

.... A stereo system is the altar to the god of music.

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