Hi everybody I'm back playing with the 29 LTD Classic.
This radio has been my "test subject" for experiments since the beginning, one day I dropped a live component
(a loose but wired potentiometer for a variable carrier experiment) Inside the radio.
Ever since that day the receiver has not worked. [Something went short circuit, "heard" a spark]
The radio transmits fine, the pa function works great, LED for tx/rx switching works.
No meter movement (Using a known s-meter, and the swr/rf switch is in the correct position)
Microphone & antenna connected.
Still no signal gen yet so I even tried transmitting with a good radio in the next room over & the meter never budges.
Attached 8-digit freq. counter to R61 then PTT and I'm transmitting on frequency
(close anyway on ch. 28 I get 027.28480 & not 027.28500).
I don't want to go through life shot-gunning problems, troubleshooting is important to me.
Last night I stumbled upon Radio Tech's own forum and found:
"Understanding how CB radio works"
Following some things I read, I attempted to find a 10.240 Mhz signal at Pin 2 of the PLL
[With the notch facing west Pin 1 would be at "bottom left corner", like a standard MCU I assume.]
No dice, the counter reads some strange frequencies but never locks-down solid, most of the time it's reads 0.
I guess either:
A) The dc blocking capacitor I used at the end of my counter should be removed.
B) PLL is not getting the correct voltage during rx.
C) PLL is bad (or I have the wrong pin?).
Quote from the thread:
"The PLL chip has a divider circuit that produces this signal so it is internal to the chip"
I assume he means that the internal divider has failed?
Is that possibly my problem: a partial failure of the PLL?
It's locking for TX & just will not for RX (I think)
[Where should I probe to confirm the failure, I assume the VCO is okay as the unit will TX]
As a side note I cannot find TR30 in this radio to save my life!
If you could provide some input, please let me know what you think.
Thank You Gents
-Leap
This radio has been my "test subject" for experiments since the beginning, one day I dropped a live component
(a loose but wired potentiometer for a variable carrier experiment) Inside the radio.
Ever since that day the receiver has not worked. [Something went short circuit, "heard" a spark]
The radio transmits fine, the pa function works great, LED for tx/rx switching works.
No meter movement (Using a known s-meter, and the swr/rf switch is in the correct position)
Microphone & antenna connected.
Still no signal gen yet so I even tried transmitting with a good radio in the next room over & the meter never budges.
Attached 8-digit freq. counter to R61 then PTT and I'm transmitting on frequency
(close anyway on ch. 28 I get 027.28480 & not 027.28500).
I don't want to go through life shot-gunning problems, troubleshooting is important to me.
Last night I stumbled upon Radio Tech's own forum and found:
"Understanding how CB radio works"
Following some things I read, I attempted to find a 10.240 Mhz signal at Pin 2 of the PLL
[With the notch facing west Pin 1 would be at "bottom left corner", like a standard MCU I assume.]
No dice, the counter reads some strange frequencies but never locks-down solid, most of the time it's reads 0.
I guess either:
A) The dc blocking capacitor I used at the end of my counter should be removed.
B) PLL is not getting the correct voltage during rx.
C) PLL is bad (or I have the wrong pin?).
Quote from the thread:
"The PLL chip has a divider circuit that produces this signal so it is internal to the chip"
I assume he means that the internal divider has failed?
Is that possibly my problem: a partial failure of the PLL?
It's locking for TX & just will not for RX (I think)
[Where should I probe to confirm the failure, I assume the VCO is okay as the unit will TX]
As a side note I cannot find TR30 in this radio to save my life!
If you could provide some input, please let me know what you think.
Thank You Gents
-Leap
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