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959 stuck on channel 33

Kung Fu Panda

Member
Jul 5, 2018
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Hello I have a 959 galaxy that’s stuck on channel 33. I tried a new front board that I had spare and same thing. Checked for cold solder joints anyone had this problem before.
 

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Is it actually receiving and transmitting on channel 33, or is that just what the frequency display says ? Can you hear it on a test radio nearby ? Does it only receive/transmit on 33 no matter where the channel knob is set ? Does it have one of those ribbon cables connecting the front board to the PLL? If so try wiggling the ends and see if that does anything... Could also be a PLL problem of some kind; like the VCO is out of range..
And the big question.....has it been previously had the golden screwdriver treatment ?
I'm not super familiar with those radios, but the frequency display on many CB's is often just that, a display, as opposed to a real frequency counter..........
 
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Is it actually receiving and transmitting on channel 33, or is that just what the frequency display says ? Can you hear it on a test radio nearby ? Does it only receive/transmit on 33 no matter where the channel knob is set ? Does it have one of those ribbon cables connecting the front board to the PLL? If so try wiggling the ends and see if that does anything... Could also be a PLL problem of some kind; like the VCO is out of range..
And the big question.....has it been previously had the golden screwdriver treatment ?
I'm not super familiar with those radios, but the frequency display on many CB's is often just that, a display, as opposed to a real frequency counter..........
It’s receiving and transmitting on 33 only no matter what channel it’s on.
 
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It’s receiving and transmitting on 33 only no matter what channel it’s on.
I'm no Galaxy expert; hoping someone else will chime in who knows these radios better than I...... But the symptoms pretty much point to the channel selector, the circuitry on the encoder side of the PLL and any associated connectors/cables.

If the PLL itself was bad, it's unlikely the radio would tx and rx at all, or it would be stuck on some way out of band frequency.
 
But the channel display shows 18.

Does the channel display change with the selector? If it does and the frequency counter doesn't, could be the freq counter board.

As mentioned above you need to verify what channel you tx and rx on.

Mods?
Has it worked normal before
Did the symptom start after any specific event?

Very little background info in the original post.

Ps I watched that movie with my kids years ago and it was actually pretty funny!
 
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But the channel display shows 18.

Does the channel display change with the selector? If it does and the frequency counter doesn't, could be the freq counter board.

As mentioned above you need to verify what channel you tx and rx on.

Mods?
Has it worked normal before
Did the symptom start after any specific event?

Very little background info in the original post.

Ps I watched that movie with my kids years ago and it was actually pretty funny!
I put a whole other face on it ,counter ,channel selector the whole thing and does the same thing on that face. Looks to be stock. Was received like that.
 
Even tho I had one of these, I no longer have the schematic, nor am I familiar with the switching network in it to begin with. Some local weenie down here in SWF "bought" it --- but never paid for it.... :mad:

That said (and given your troubleshooting progress so far) I would look for a 4, or 8 pin DIP chip designated as the "optocoupler" on the rig's schematic, within the PLL / channel selector chain.
Check it's input voltage for spec.

Again: I'm not looking at an actual schematic at the time personally, but I'm sure you will zero right down on it IF you have access to the 959's schematic. This chip (or the supoply to it) is the "usual suspect" in the 'chain', given your description of the problem and progress so far.
 
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On channel 32, all of the binary inputs are high. At ch33, they all roll over to low (which forces the internal P7 high). Being these binary inputs have pull down resistors, it would stand to reason that the channel selector is not getting its supply voltage and keeping all the binary inputs low (which keeps the radio on ch33).
 

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