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GE Superbase clarifier unlock

Lkaskel

Lkaskel

Well-Known Member
Aug 4, 2017
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SO, another "challenge". I have a GE Suprebase that I waned the clarifier unlocked. I followed the method posted on Secret CB Volume 10.

1)Solder a wire on the unused side of the clarifier , the other end goes to the emitter of Q216 (9 volt source)

2)Cut R-221

3) Remove D-204 and replace with a jumper wire.

4)Cut R-205

I did not cut R-221 or R-205. I desoldered one leg and lifted it out from its hole. I have 8.77VDC at the wire run to the clariier.

When this mod was complete the radio now will not throw a carrier on am or transmit any power on SSB. It was working fine before the mod. I have triple checked the mod, which is actually simple to do and all seems ok.

Any thoughts?
 

That radio is famous for intermittent soldering issues, especially on the lower circuit board. See if pressing on the board, especially around the single-row connector pins to see if transmit power will flicker on briefly while you're keyed.

73
 
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nomadradio said:
That radio is famous for intermittent soldering issues, especially on the lower circuit board. See if pressing on the board, especially around the single-row connector pins to see if transmit power will flicker on briefly while you're keyed.

73
Click to expand...
Great suggestion!!!! I did resolder all of the pass throughs when I re-capped it. Pressing on it did not help. I do have good voltage at the regulator (Q216) and I also have voltage at the bias points. I did notice that when testing the driver and final I had over 12vdc on the collector at transmit and the schematic shows I should have 6vdc. Hmmm. I did the clarifier mod perfect. I cannot understand how that caused a transmit issue. Also, I have reversed the clarifier mod and put it back to factory.

Thanks Nomad!!
 
The DC voltage to the driver and final collectors will only drop to 6 Volts in AM transmit mode if the radio is delivering a carrier. The current drain from the driver and final are needed to drop the voltage across the big, white ceramic carrier-set control. So long as the driver and final have no carrier driving into them, they draw no current. Hence no voltage drop from 12 Volts down to 6.

That's why you see that reading.

73
 
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nomadradio said:
The DC voltage to the driver and final collectors will only drop to 6 Volts in AM transmit mode if the radio is delivering a carrier. The current drain from the driver and final are needed to drop the voltage across the big, white ceramic carrier-set control. So long as the driver and final have no carrier driving into them, they draw no current. Hence no voltage drop from 12 Volts down to 6.

That's why you see that reading.

73
Click to expand...
Thanks for that Nomad!! Now to figure out why there is no carrier.
 
I know this is a bit late but I just saw it. The CB Secret book had a misprint. It should be disconnect D205 not R205. If one looks at the schematic R205 has nothing to do with the clarifier. Since there will be a constant voltage on the clarifier after connecting the wire to it, the TX only voltage source needs to be disconnected. So lift D205. There is actually no need to lift D204. It was there to stop the TX only voltage from going to the clarifier. It would also be best to use about a 15K resistor at Q216 instead of connecting the wire directly to it .
 
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tramd said:
I know this is a bit late but I just saw it. The CB Secret book had a misprint. It should be disconnect D205 not R205. If one looks at the schematic R205 has nothing to do with the clarifier. Since there will be a constant voltage on the clarifier after connecting the wire to it, the TX only voltage source needs to be disconnected. So lift D205. There is actually no need to lift D204. It was there to stop the TX only voltage from going to the clarifier. It would also be best to use about a 15K resistor at Q216 instead of connecting the wire directly to it .
Click to expand...

Tramd, thanks for your reply!! I had put the radio on the shelf to work on other projects but I am going to get it back out and finish it. I was 99% there until I had the xmit freq problem and then the clarifier unlock/no transmit problem. Do you think that because I disconnected R205 and left D205 in place that it caused the final to go? Still trying to determine the no xmit issue.

Thanks again!!
 

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