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What is so special about a GE superbase anyway?

Update: tp1 is not adjustable. Its solid at 5.5v and its supposed to be adjusted to 3.6v. When turning the VCO, i can hear shifting as if dialing in a portable AM pocket radio but nothing audible just hissing. Then, there are more issues. The tx light is flickering on and off while in rx mode. The audio has a squeal past half volume. I turned it off and Im gonna try it again later to see if the faults are immediate or only after it warms up. There was a switch in the back with 2 long wires but that went nowhere. Since I did see that the big cap area was cleaned and that cap was replaced, there could still be issues eith other caps causing this mess. Would anyone know if my VCO is still good because I can hear tuning when I turn it? Or isbit screwed because tp1 has a solid 5.5v and wont adjust to 3.6?
 
Its odd as heck. The schematic shows a 5.5v source feeding 1 side ofvthe VCO. There is an output that goes to pin 1 IC201 and it says 2.7v. Hand written. Something doesnt make sense.
 
TM86 said:
Two possible VCO sources for replacements:
www.microchipz.net

VCO Units | Microchipz

Replacement VCO units for Cybernet vintage CB radios
www.microchipz.net www.microchipz.net

Or you can follow this video on how to fix one:
Click to expand...

Great video. Ive seen a lot of his videos. Pretty easy to restore the VCO it seems. I just have to figure out how to test the block for functionality first.
 
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Lots af great info. Thanks guys. Im gonna recap the mofo andcsee wherevthst gets me. Something tells me that the vco msy still work and if not, I'll borrow one from one of my other cybernet chassis.
 
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Had a VCO on a Superbase die here. Radio was recapped and worked great for a few years, then one morning no transmit or receive when it was turned on. After about a hour it came good but 5 minutes later died again. TP1 voltage stuck on 5.4v and moving the VCO screw made faint sounds in the speaker like tuning an old shortwave radio as it was rotated, and TX light flickering when dead keying on AM. Tech explained how to change the VCO (delicate and expensive to ship a radio that big interstate!). Microchipz VCO v1.1 (order code VCO11) is the correct one for the Superbase:

https://www.microchipz.net/vco-units

Replaced this part and it's working great again. Cost about $25 aussie with shipping from England to Australia.
 
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hpssb said:
Had a VCO on a Superbase die here. Radio was recapped and worked great for a few years, then one morning no transmit or receive when it was turned on. After about a hour it came good but 5 minutes later died again. TP1 voltage stuck on 5.4v and moving the VCO screw made faint sounds in the speaker like tuning an old shortwave radio as it was rotated, and TX light flickering when dead keying on AM. Tech explained how to change the VCO (delicate and expensive to ship a radio that big interstate!). Microchipz VCO v1.1 (order code VCO11) is the correct one for the Superbase:

https://www.microchipz.net/vco-units

Replaced this part and it's working great again. Cost about $25 aussie with shipping from England to Australia.
Click to expand...
Thats EXACTLY what mine is doing. Thanks mate! Im gonna look into this today!
 
I contacted microchipz and this is what they told me. Is there anyone else in thevforum that can vouch for the VCO version 1.1 from these guys before I send them a bunch of money? Shipping to Canada is crazy money from the UK. Here's that screen shot of what he said...1000021381.jpg
 
Sorry for the delayed replay, wanted to ask out tech why they may had had trouble.

The RF board has pins that connect one side of the board to the other and these are a common source of trouble. It's possible that one or more of those was disturbed when they replaced the VCO.

I can only speak for the only one I've done here last year. That radio had a major service - all electrolytics and most of the troublesome pins replaced, and a full cleanup / alignment - two years before the VCO died, so in our case the dead VCO was the only faulty part. Replacing it got the radio working perfectly again.

The tech we use normally uses these in GE Superbases and B models (the mobile version with the dual clarifier):

Spectrum UK ebay link

These have always worked well. The right one of the VCO27 (not the A or B versions, those are for Euro market radios). She only suggested the microchipz ones after Spectrum comms (the usual supplier above) had none listed and were not answering messages at the time.
 
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