| Author |
Message |
    
Jose22
| | Posted on Friday, April 19, 2002 - 7:53 pm: | 
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had a cobra 29LTDwx brought in that had no voltage on lock pin of PLL. (unlocked). Owner claimed he tuned radio last night and worked good. This morning radio did not work.. Now only has small static. NO TX or RX. Suspected he unlocked by screwing around with VCO . Tuning CAN with wax on it showed it had. Started to retune cans to get proper output on Scope and correct voltage but can tuning had no effect. Took heat gun to melt off great deal of wax around IC2 (TA7310-1) to get at test point better, and while hot radio started to RX. When cooled in 20 seconds, quit again. Looked for breaks, resoldered IC2 , no response. output on crystal is dead on according to frequency counter. Got any answers?
Thanks Jose22 |
307
| | Posted on Monday, April 22, 2002 - 7:13 am: |
|
I would suspect that the small 1uF Capacitor that is in the PLL Loop back is bad. They tend to have thermal problems after a while. It is the small "blue" tantalum capacitor near the PLL IC.
307 |
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