motorola gm300

[jmcelyea]

Does anyone know what ohm coupling caps was used on the gm300 uhf with m1107 output 30-45 watt pa canno't find it on the diagram. thanks Jack

[Bill_G]

Very high.

[jackhackett]

Capacitors aren't measured in ohms, and "coupling caps" is a pretty vague description.

I'm guessing you mean the caps on the PA transistor, which if I recall correctly are different for different band splits and don't have values on the schematic. Since you mention the diagram I'm going to assume you have the service manual... you should be able to find the part numbers and values in the parts list, but they're not listed with the rest of the caps, they're in the section with the PA transistor.

I'm going from memory on that.. I can check the manuals tomorrow to be sure.

[jmcelyea]

Then only service manual i have is on m120 it lists c2641 43pf-500v
c2642 43pf-500v
c2643 39pf-500v
c2644 39pf-500v
just making sure the ones in the 300 are smoked also m1107 final output.
thanks Jack

[jackhackett]

Well, the capacitors I was thinking of are listed under the "pa hardware kit" section of the parts lists, but also shown on the schematic.
The M1107 appears to only be used in the 10-25W 438-470MHz PA
Caps on the PA final in that one are:

qty / value / moto #
2 / 43pF 500V chip / 21-80060M34 on the input side
2 / 39pF 500V chip / 21-80060M33 on the output side

[jmcelyea]

Thanks a lot for the help i lost my service manual on the gm300.