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Galaxy dx99v Driver bias too low need help

jef

Member
Mar 3, 2013
32
5
18
Have a few Galaxys with the same problem the driver bias is too low like 35 ma max can't get the 50 to 75 they want .2 of the radios are galaxy 99v's and 1 dx88hl they all work great but vr11 is maxed and only reads 35 ma the final vr10 and vr 20 I can get set correctly on all 3 but the driver bias is low on the 2166 drivers.The radios seem to work fine but would like to fix it correctly.Any help is appreciated Jef
 

There can be something wrong with 2166 itself. Also with bias diode D112. You can use 1n4148 as replacement.
Mike
I thought bias diode for the driver was d69? I will check all3 d69 d112 and d68.Cleaned vr 11 well, it's working checked it with an ohm meter through its range,.I was thinking maybe a disc cap electrolytic or resistor in the neighborhood may be at fault but don't know where to start. .Need to get more ma to the vr11 somehow.I will try a different 2sc2166 if I can find one around here if it is the driver transistors all 3 are bad on all 3 radios could that be the output wattage is fine onall of them.
 
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Did you actually test the driver bias diode (MV1Y) yet?

Both the early and late 99v schematics show it as D89. D90 is a 1n4148 diode; you can check that one too. Also check the driver transistor as sp5it said. It isn't a complicated circuit to work on, so I would also check all of the solder joints in that area first.

Snapshot_2017-11-18_16-42-55.jpg
 
Last edited:
Did you actually test the driver bias diode (MV1Y) yet?

Both the early and late 99v schematics show it as D89. D90 is a 1n4148 diode; you can check that one too. Also check the driver transistor as sp5it said. It isn't a complicated circuit to work on, so I would also check all of the solder joints in that area first.

View attachment 22031
Thank you very much you 2 the 2166 was bad on one radio and the diodes on the others, you guys nailed it!.
 

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