Texas Ranger TR 966/ Galaxy 949 PLL alignment question

[Handy Andy]

No, 5kHz is 5,000Hz -

I know the feeling - those Hertz can really Hertz! - er Hurts...

But take heart, in knowing that you not alone, amongst the many.

Then, if you have that kind of drift, that may mean more of the RF Oscillator NPO caps are bad. Simple temperature and humidity changes and they're all over the band ...

So look for those "black capped" disc caps by the Xtals and coils - they'll read with single or two digits stamped on them like 4 or 22 or even 33 or 47 - (Not 472 or 471 or even 473 - 1 to 2 digits not 3 or more) - these may need to be replaced - you can even verify the ones that are bad by placing a hot soldering tip on the cap body and look at your counter or hear the drifting results from them - then you have found one that is bad - it does not take much heat for the bad ones to show up while you listen in your receiver. Do it for all modes, to help reduce this drift problem - replace with better quality, higher tolerance, units of the same value, if you can.

 

[Robb]

You might also give the clarifier control a little spritz of Deoxit, like LC referred to. I think that you will find the issue is a bad xtal - either the 10.240 or the 15.360. But also check out the solder joints too; a cold joint could make freq shift suddenly. Most of the issues I found were either the xtals or the 10v cap on the pll or the regulator cap - or both.

 

[000]

Robb is right. Check each frequency at the test points (TP #) you need to isolate the circuit that is drifting. 10.240, 15.360 etc....

 

[Robb]

Robb is right. Check each frequency at the test points (TP #) you need to isolate the circuit that is drifting. 10.240, 15.360 etc....

That was just my personal experience.
YMMV

 

[loosecannon]

you might also check C130.
the 949 schematic shows a 20pF NPO capacitor there, but have heard of values up to 30pF being used.
be sure to use an actual NPO cap if you choose to replace it.
LC