PRO96 , is it worth getting it fixed

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lukaradio

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It appears to have drifted off the 800mhz......apparently common?, would it be worth paying someone to fix it? Has anyone had any luck on his kind of "repair"?
 

kb3isq

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I had the same problem with a PRO 96. When I manually selected the control channel it showed very low % (4-20) while my other radio showed 80-95. I adjusted vr4 and the % went up comparable and it started receiving again.
 

Ronaldski

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lukaradio

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Yes G&G is 50 bucks but I think the extra $ for shippping to and from might be the deal breaker?

Not sure if I`m daring enough to give it a try, more concerned about making things worse rather then better if I open it up and try??
 

hiegtx

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Yes G&G is 50 bucks but I think the extra $ for shippping to and from might be the deal breaker?

Not sure if I`m daring enough to give it a try, more concerned about making things worse rather then better if I open it up and try??
Think of it this way:

If $50 bucks plus shipping each way (and maybe parts) is a deal breaker, then unless you find somebody local, you probably are not going to fix it. In effect, you'll no longer use it.

If you attempt the repair, and are successful, you have a working scanner. If it does not work, or goes south on you (fails), you really have not "lost" anything, because it was not worth (to you) the cost of outside repair service, In a sense, it was already written off. Of course, you could use it, perhaps, for bands other than 800MHz, but if that's the one you need, it becomes a case of fix it, or dump it and get another working unit.
 

lukaradio

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If you have a Phillips and a small flat screwdriver - like for eyeglasses is all one needs besides a bit of courage and patience.
See these -
http://forums.radioreference.com/radio-shack-scanners/269559-pro-96-adjust-tc1.html
http://forums.radioreference.com/michigan-radio-discussion-forum/292753-mpscs-towers.html

For locating VR4 PRO-96 Internal Adjustments - The RadioReference Wiki
Maybe you would be so kind and offer suggestion on the level of skill / difficulty needed to pull this repair off, reading other threads it sounds like you have some experience.
I`m not scared to open it up and try, its more of what percentage I will have for a successful repair.
But of course my eyes are getting older so I might have to pull out a magnifier to help see.
 

Ronaldski

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Yeah a magnifying glass can be handy on vr4.
Just getting that small flat screwdriver and gently fitting it into the slot on vr4.
I've done a few, I would rather guess go about 10 % counterclockwise seem to recall is a good start.
Id be sure to have the radio off especially if your new to this sort of thing.

Know a ham radio operator in the area? They like to tinker on this stuff.
 

lukaradio

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Would it be safe to say if I mark the original position of the vr4 I can always turn it back if it doesn`t work out? OR once you start to adjust there is no turning back?
Waiting for an answer with screw driver in hand!
 

lukaradio

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UPDATE....finally with much tinkering I kind of got it to work....kind of. I got some regular motorola trunking going on the 800, but this now looses the digital stuff I was listening to around the 143mhz.
So its either one or the other???
Would still playing with the vr4 get it back on track properly?
Would turning the vr4 further around have any effect?
Would updating the DSP help?
Any further suggestions?
 
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pro92b

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Here is the text from the service manual that tells how to set VR2, VR3, and VR4.

1. Set the signal generator freuqency to 173.390 MHz (No modulation). Select channel 006 and adjust VR4 so the frequency is 455 kHz +/- 10 Hz.

2. Set the signal generator freqeuency to 173.420 MHz ( No modulation). Select channel 007 and adjust VR2 so the frequency is 455 kHz +/- 10 Hz.

3. Set the signal generator frequency to 154.5475 MHz (No modulation). Select channel 008 and adjust VR3 so the frequency is 455 kHz +/- 10 Hz.

It isn't clear that VR4 affects only 800 MHz and your experience suggests there is more interaction to the adjustments than most people are aware of. Without suitable test equipment, a signal generator and frequency counter, you will not be able to determine what the problem is nor will you be able to correctly align the radio.

If the root of the problem is drift in the master oscillator (TCXO), replacing that component may be the only real fix because the TCXO is not adjustable. Adjusting VR2, VR3, or VR4 will not compensate for a TCXO that has drifted off frequency.
 
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