Author |
Message |
Ironmike
Junior Member Username: Ironmike
Post Number: 11 Registered: 6-2007
| Posted on Wednesday, October 21, 2009 - 12:48 am: |
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What would cause an old 23-channel 135 to drop in frequency? For example- keying up at 27.185 and dropping .165, .125, . 26.995 etc in a few seconds? Also it seems that some blocks of 4 channels seem to work ok. 17-20 seem to have the most trouble. |
Moderator120
Moderator Username: Moderator120
Post Number: 482 Registered: 11-2006
| Posted on Wednesday, October 21, 2009 - 10:59 am: |
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Ironmike, I have no idea, but my Tech loves those radios. I just sent him an email, if he has any ideas I will post them here for you as soon as I get an answer! Mike Moderator120 CEF#0120/HAM #222 KB1NYD CVC#0041
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Wcsd106
New member Username: Wcsd106
Post Number: 2 Registered: 10-2009
| Posted on Friday, October 23, 2009 - 5:39 pm: |
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Sounds like you have a crystal dropping out. Those 23 channel radios had crystals that controlled about 4 channels each. |
Moderator120
Moderator Username: Moderator120
Post Number: 484 Registered: 11-2006
| Posted on Saturday, October 24, 2009 - 7:03 pm: |
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Ironmike: sorry for the delay, he did send me a reply. And Wcsd106 is right on the money. But here is what my Tech had to say on this topic: His problem is a bad crystal, or a the oscillator for that crystal. Most likely bad crystal though. The clue was that the banks of 4 channels. In most 23 channel controlled radios they linked 1 crystal which controlled 4 channels. So the match is to figure haw many sets of 4 fit into 23 . One other possibility is that it could be a dirty contact on the channel selector knob, but I doubt that is the issue he is having. That's pretty much at the bottom of the list, where the crystal being the culprit is at the top of the list. It may be thermally intermittent. This means that it is ok at first because it is running with no load, then it is switched on when the PTT is pressed. As it starts getting voltage and current through it, it begins to heat up quarts. This causes the quarts to expand, therefore changing it's internal capacitance / frequency, and hence the change in transmitted frequency. Find crystal linked to that group of 4 channels, and replace. Mike Moderator120 CEF#0120/HAM #222 KB1NYD CVC#0041
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Ironmike
Junior Member Username: Ironmike
Post Number: 12 Registered: 6-2007
| Posted on Sunday, October 25, 2009 - 10:30 pm: |
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I sure do appreciate it. I wonder if it is worth ordering a crystal to see. Maybe your tech would be interested in some business? |
Moderator120
Moderator Username: Moderator120
Post Number: 486 Registered: 11-2006
| Posted on Monday, October 26, 2009 - 6:51 pm: |
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I would think it would not be worth the money to be honest, but if you love the radio and have the money then you go for it. The shipping of the radio would really drive the price up as well. Mike Moderator120 CEF#0120/HAM #222 KB1NYD CVC#0041
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Tech291
Moderator Username: Tech291
Post Number: 538 Registered: 11-2004
| Posted on Monday, October 26, 2009 - 8:51 pm: |
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a better source is to find a junker that uses the same crystal layout.shouldnt be to hard to find as there were only about 3 common layouts in popular use by most of the manufacturers. tech291 cef291/cvc6 kc8zpj |
Ironmike
Junior Member Username: Ironmike
Post Number: 13 Registered: 6-2007
| Posted on Monday, October 26, 2009 - 10:53 pm: |
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Well, that's true- but SSB radios had a different scheme. I have a cam 89 and a courier conqueror II but they are AM. |
Bruce
Senior Member Username: Bruce
Post Number: 5215 Registered: 9-2003
| Posted on Tuesday, October 27, 2009 - 6:20 am: |
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Jan crystals ft myers fl |
Ironmike
Junior Member Username: Ironmike
Post Number: 15 Registered: 6-2007
| Posted on Wednesday, October 28, 2009 - 11:51 pm: |
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Now that brings back memories... Them and Bomar... |