Galaxy 66 low to no power

[rayray1963]

Got this in a trade. It talks but has no power output at all. Final is good. Keys up and can hear it transmit on a monitor radio just has no power. I'm thinking voltage regulator. The variable on it doesn't move the dead key either.


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[MDYoungblood]

Does it receive and did you check the driver also.

3's

Greg

[rayray1963]

Does it receive and did you check the driver also.

3's

Greg

Yes the RX is good. Figured out its in the VCO area. That's out of my league, guest I'll sent it in to CB Supertech and see if he can save it.

Thanks


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[TheCBDoctor]

Hi rayray1963

If the radio receives then it won't be in the VCO. Check and see if you have 4 to 6 volts on the Final of the collector. You can measure it at the tab. It sounds to me like the AM modulation transistor or a component supporting that circuit has failed. That would be the large PNP transistor next to the Final on the right rear side. It may also be the A-473 or the 2SC-945.

They all work together to create a current amplifier. Without voltage at the Final the radio will not have output. The fact that a near-by radio picks up a signal tells me the radio is transmitting, but is not being amplified by the Driver or Final because there is not voltage on the collectors.

Modulation is created when the current changes at an audio rate as you speak using the Modulation transistor. I believe it is a B-754 or any of the other large PNPs, such as, the B-688. Some of the cheaper radios will use the an A-473 T-220 case style.

Check the modulation transistor first by measuring to see if there is voltage on the collector of the Final. If it is missing you can fix it cheaply and by yourself.

Good Luck

[rayray1963]

Hi rayray1963

If the radio receives then it won't be in the VCO. Check and see if you have 4 to 6 volts on the Final of the collector. You can measure it at the tab. It sounds to me like the AM modulation transistor or a component supporting that circuit has failed. That would be the large PNP transistor next to the Final on the right rear side. It may also be the A-473 or the 2SC-945.

They all work together to create a current amplifier. Without voltage at the Final the radio will not have output. The fact that a near-by radio picks up a signal tells me the radio is transmitting, but is not being amplified by the Driver or Final because there is not voltage on the collectors.

Modulation is created when the current changes at an audio rate as you speak using the Modulation transistor. I believe it is a B-754 or any of the other large PNPs, such as, the B-688. Some of the cheaper radios will use the an A-473 T-220 case style.

Check the modulation transistor first by measuring to see if there is voltage on the collector of the Final. If it is missing you can fix it cheaply and by yourself.

Good Luck

Thanks for the information. I haven't had much time to look at it again. Will check your suggestions this weekend.


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