How do you deal with alignment challenges??????

[Lkaskel]

Ok, I have this Galaxy 99v2 that refuses to be aligned. I have it sorted out (I think) and all I need to do is align it.

#1 is the frequency alignment. I can align this to dead on, put the cover on and 30 minutes later its up to 400Hz off. It appears that the PLL mixer coils (L20, 21 and 22) seem like they have some play in them. When I turn the radio upright (speaker down) the tuning slugs shift and it goes out of alignment.

#2 is the mic adapter/audio injector seems to have feedback with this radio only. What do you use for audio injection for alignments?

#3 - Man these Galaxy radios are hard to align for frequency!!!! What tool do you use to destroy a radio when it gives you too much trouble? I am torn between a baseball bat and a golf club. A shot gun seems like it would have the most satisfying result but...the neighbors would complain.....

 

[TM86]

Thermite. I'd suggest tannerite, but those neighbors of yours would like that less than shotgun rounds being fired.

 

[loosecannon]

yes the ranger boards sure do have some touchy freq cans.
they are also notorious for twisting off the tips of your alignment tools.

when you say "feedback" what do you mean? like, when you inject a signal in to the radio, it starts to squeal as if you've turned a power mic up too high?
if so, look for parts value changes in the mic amp section as well as limiters cut and VR's cranked.

as for the instability on frequency, you might check all the case screws and make sure they are tight, as well as a general inspection of the PC board traces looking for cracks.
also, when things seem to change with moving the radio around, think about how sections of the radio can act like tiny antennas if one of their tuning cans opens up, or maybe a bypass cap has a bad solder connection.

when a radio starts to exhibit very strange issues, i like to take the radio's history into consideration when troubleshooting.
was it installed in a big truck that drove down dirt roads all day long?
or maybe the bracket was the wrong size causing the radio sides to be bent and stressed?
LC

 

[nomadradio]

If the three trimmer coils for the PLL are that touchy, sounds like maybe someone has worn down the inside of the coil by repeated tweaking? Stabilizing those tiny slugs without making them seize up is easier said than done.

The adjustment range of those coils is usually a couple of channels, or close to it. Makes any tiny disturbance of the slug into a noticeable bump in frequency.

Had a friend years ago who tamed the temperature drift in his Saturn base. Removed a PTC thermistor from a dead camcorder. This is a single piece heating element and thermostat. Served to keep the spinning tape head in the camcorder from getting cold enough to condense moisture from the air. He plastered one of these to the PLL crystal and trimmer cans. Installed a 5-Volt regulator chip on the unswitched DC side of the power supply, and powered the thing from that. So long as it remained plugged in, the PTC would keep the crystals/coils warm, then turn down the heat as the inside of the radio warmed up. Had the only Saturn in town that didn't drift on sideband.

Never could get a part number from him. Said he didn't have service data for that model. Hinted that could have been connected to the decision to scrap it.

Maybe one of these days I'll study that kind of component enough to try obtaining one to do that job. Not this week, though.

73

 

[loosecannon]

here is a great video on doing something like Nomad is talking about:


however, the part he uses in the video is now obsolete.
I asked him in the comments if he now uses something different.
LC

 

[secret squirrel]

Mr Loosecannon and Mr Nomadradio have covered this topic with detail worthy of paid consultants. I am not a radio tech, I am a computer hardware tech and I reoccurring problem with no explanation with everything in spec in a PC is common issue. Most time the true issue can be tracked down by reviewing the history of the device. Specs on paper do not always transfer to mean fully operational in real word situations. Best of luck my friends.

 

[Lkaskel]

Thanks everyone for your replies!!! Unfortunately, the history of this radio is not super clear BUT it is obvious that someone had been in it to do mods like the clarifier unlock (which I restored to factory) and an upgraded regulator as well as replacing the driver and finals with some unknown fakes. The soldering on this unit was not that great as well so I am assuming that the person that did the mods was not as on point as maybe they should have been. We have all worked on radios like this though. There is no point returning it unless I can be sure that the frequency is stable. I will just keep on plugging away at it to see if I can come up with any ideas to help the IF cans be more "stable".

Thanks as always!!!!