Need some help here.Got an early uniden grant that doesn't transmit on am and ssb but pa works.Also squelch does not work.Any help would be great.
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
early uniden grant squelch not working
- Thread starter American-Vulture
- Start date
Ahh, "squelch does not work"?
Does this mean you can't hear receive signals?
At all?
Or does it mean you can't shut down the channel noise with the squelch knob?
First thing to find out is whether or not the radio is receiving the channel you select.
You make it sound as if the radio is not receiving OR transmitting.
There is a green LED on the front that should turn red when you key the mike.
Does it come on green? Does it turn red when you transmit?
That LED can serve to suggest where to check first.
Is this radio just a "Grant", or a Grant XL?
There have been almost a dozen different radios sold since 1979 or so with the name "Grant" on the front. Would help to narrow down which one you have.
73
Does this mean you can't hear receive signals?
At all?
Or does it mean you can't shut down the channel noise with the squelch knob?
First thing to find out is whether or not the radio is receiving the channel you select.
You make it sound as if the radio is not receiving OR transmitting.
There is a green LED on the front that should turn red when you key the mike.
Does it come on green? Does it turn red when you transmit?
That LED can serve to suggest where to check first.
Is this radio just a "Grant", or a Grant XL?
There have been almost a dozen different radios sold since 1979 or so with the name "Grant" on the front. Would help to narrow down which one you have.
73
Yes the squelch does not shut of f the channel noise and does not transmit.
Its the old grant xl with the faceplate like the president radios with some push buttons on it.
Its the old grant xl with the faceplate like the president radios with some push buttons on it.
Alrighty. This appears to be the FCC-legal 40-channel (only) version of the radio.
If I'm right, it has a 5-pin mike socket. That detail alone will tell us which radio you have for sure. I should have asked about that to start with.
The radio with the 4-pin socket is totally different on the inside.
The squelch problem and the transmit problem would appear to be two separate failures.
Do you have another radio you can use to listen for a weak transmit signal coming out of the Grant?
If you can hear a weak transmit signal on AM or SSB (or both), this narrows down where to look next.
Do you have any of the typical resources on hand for making repairs?
A dummy load and wattmeter?
A multimeter?
Soldering and desoldering tools?
Good chance that the failure in the transmit side is a part that's soldered in place.
Could be that a shot of control cleaner would make the squelch control work again.
Maybe.
73
If I'm right, it has a 5-pin mike socket. That detail alone will tell us which radio you have for sure. I should have asked about that to start with.
The radio with the 4-pin socket is totally different on the inside.
The squelch problem and the transmit problem would appear to be two separate failures.
Do you have another radio you can use to listen for a weak transmit signal coming out of the Grant?
If you can hear a weak transmit signal on AM or SSB (or both), this narrows down where to look next.
Do you have any of the typical resources on hand for making repairs?
A dummy load and wattmeter?
A multimeter?
Soldering and desoldering tools?
Good chance that the failure in the transmit side is a part that's soldered in place.
Could be that a shot of control cleaner would make the squelch control work again.
Maybe.
73
Yes I have a lot of tools.Including a silly scope. Also a complete set of Cb Sams.
Its dead no output at all I could connect it direct to another radio and it would not do anything to the attached one.,receive is good.
8 volts at regulator when keyed.Finals have 13.8 volts in rx.
Regulator looks good.
Its dead no output at all I could connect it direct to another radio and it would not do anything to the attached one.,receive is good.
8 volts at regulator when keyed.Finals have 13.8 volts in rx.
Regulator looks good.
Last edited:
C95 is a very good place to look. It filters the 8-Volt transmit-only source to pin 6 of IC3, the AN612 balanced modulator chip. Should have just under 8 Volts DC in transmit mode only. If C95 fails as a short, it will probably overheat R108, the 100-ohm resistor that feeds into it. R108 should get replaced any time C95 is found shorted.
73
73
Last edited:
I have a cobra 148gtl that the tx output quits 100% after being keyed a couple of times.
I unplug it and put it aside for a day or so and it works again with the same problem.
Sounds like the same problem as with the Grant ?Might be same cap?
I just ordered a bunch of them see what happens.Higher voltage .
I unplug it and put it aside for a day or so and it works again with the same problem.
Sounds like the same problem as with the Grant ?Might be same cap?
I just ordered a bunch of them see what happens.Higher voltage .
Does it shut down on AM transmit only?
Try sideband when this happens and see if it's still alive that way.
If it cuts out in AM transmit ONLY, this points to TR41, the AM modulator transistor.
And if it goes dead in SSB mode as well, this points to the final or driver transistor.
Maybe.
If it quits in SSB mode and AM both, it's time to scrounge up a second radio you can tune to the same channel. See if there is a weak signal you can hear in the second radio when the power has dropped. That would point to trouble upstream from the driver and final.
You'll hear way too many suggestions to "Just change the final". Yes, it's a common thing to see fail, but first pinning down what has failed can save time and money.
73
Try sideband when this happens and see if it's still alive that way.
If it cuts out in AM transmit ONLY, this points to TR41, the AM modulator transistor.
And if it goes dead in SSB mode as well, this points to the final or driver transistor.
Maybe.
If it quits in SSB mode and AM both, it's time to scrounge up a second radio you can tune to the same channel. See if there is a weak signal you can hear in the second radio when the power has dropped. That would point to trouble upstream from the driver and final.
You'll hear way too many suggestions to "Just change the final". Yes, it's a common thing to see fail, but first pinning down what has failed can save time and money.
73
There are too many things going on with this radio.It has a channel mod ,clarifier opened,
An echo board installed,Talk back,and lastly 5 pin mic connector changed to a 4.
Do not know where to start first.Maybe return it to stock but the mic plug got me stumped.
I guess it used to have a board for the plug?
I have the grant hooked up to a watt meter and a freq. counter.Nothing shows in any mode.but it rx's.
An echo board installed,Talk back,and lastly 5 pin mic connector changed to a 4.
Do not know where to start first.Maybe return it to stock but the mic plug got me stumped.
I guess it used to have a board for the plug?
I have the grant hooked up to a watt meter and a freq. counter.Nothing shows in any mode.but it rx's.