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Anyone want to take a stab at this before I dig into it later tonight?

ButtFuzz

Anti-BS Advocate ● WO0WOO ● Reverend Doctor
Aug 11, 2005
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Sunny Salem, VA
robco.ath.cx
Radio: Major M-360. I like older radios and thought I'd add this one to my collection. Got it at a more than fair price, didn't expect it to work... and it didn't!!! Ha ha ha!

So anyways, This is a 3 band (FCC 40 - High - Higher) multimode radio. About the size of a 148 GTL. Cybernet export chassis and it uses 3 crystals (therefore only one set of n-codes) to drive a PLL02A about it's business to synthesize the freqs for the three bands. Modes available are AM-FM-USB-LSB.

Innards of the radio look pretty good (no obvious hacking) other than someone has turned RV12 all the way up (AMC), which is to be expected.

Radio powers up. I hear static on USB/LSB and FM, but not so much on AM. Needle barely moves on AM when I am near unit with portable CB transmitting on Ch 19.

When I attempt to transmit AM/USB/LSB, no power indicated on wattmeter sitting betwixt the radio and "you big dummy" load. Yes, I attempted speaking into the mic on SSB.

Not that this matters, but the mic socket has been rewired from 4 pin cybernet to 4 pin Uniden/Galaxy/RCI, etc. This is known good and not causing the problemo.

I am not at all familiar with this radio, and I'm looking for some basic troubleshooting for this chassis before I send it to a professional.

thanks,
Fuzz
 

I am a newbie at troubleshooting and radio repar. But, I like a good challenge. So here goes nothing...
Before I would test any parts with a VOM, I would look for any obvious burned parts or traces on the board - or bad solder joints.
*I would check the power amp/tr first.
*Then, I would check the audio IC
Then, I would key the mic and put a freq counter on a couple of appropriate test points to see if anything was happening when modulating thru the mic.
*If all of that fails, I would use it as a door stop.
*Or - see how it works as a frisbee...

I guess I need more patience!
 
Last edited:
I have had a few of these cybernet chassis and would bet the problem lies in the VCO. When these go bad they exhibit those symptoms.
 
Audio chip usually righthand side wall 8-10 pin chip from foil side of the board you will see the straight line or row of where the pins are soldered this is a usual spot you see peopl attach to one of these pins to get 8 volts from when doing (unlocking) a clarifier

Sorry Tony I may have missed something ,I know what the audio chip is. Just wondering why you are bringing it up.

When the vco goes out of lock you still have a hiss from speaker.
I believe you have a PLL02A chip in that radio . check to see if its in lock.
The vco coil in these sets are notorious of going bad
 
It has the "green" cybernet VCO block and it is probably bad from what I can tell.

These cybernet rigs are such a pain in the buttocks sometimes. Mostly due due to frailty of components or dry solder joints that I've seen.

I really appreciate everyone's help. More as events transpire.
 
yup, probably bad. Still wondering what Tony was going on about. I read your first post 30 times thinking I was missing something
 
and there you have it (y)
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