Galaxy DX 88HL reads really high on driver bias

[mr_fx]

the lowest I could get it to set to is 85ma or so, the service manual says 50-75ma, other than that it goes up to 186ma

I checked it on 3 multimeters with the same results each time, so any ideas?


IIRC I can just bias the driver by setting voltage right? or is there some underlying problem that needs to be addressed?

Thanks for any help you guys (and gals) can offer

 

[dxhound]

the lowest I could get it to set to is 85ma or so, the service manual says 50-75ma, other than that it goes up to 186ma

I checked it on 3 multimeters with the same results each time, so any ideas?


IIRC I can just bias the driver by setting voltage right? or is there some underlying problem that needs to be addressed?

Thanks for any help you guys (and gals) can offer

First ensure the supply voltage is 13.8 and not 15 or so......

Check R219, VR11, and R218, for proper value. Verify with an ohm meter. Preferably out of circuit, but not needed to be. If either of these were too low in value, that would cause excess bias voltage and added current.

Since d90 is attached directly to 13v (mirror board) You could check it for being "leaky" allowing reverse voltage to get into the bias path, but this is unlikely. There is also the chance that TR 44 itself is bad, and causing excessive current draw due to one or two internal junctions being shorted. Again, an outside shot.

 

[mr_fx]

thank you. basically check everything between the bias jumper and the driver