connex 3300hp fading receive

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connex 3300hp fading receive

Postby smokinjoe » Sunday 15th Apr 2007, 2:16

I have a connex 3300hp with 360014b pcb board and the receive fades out every now and then also when the radio does this the transmit will get choppy sounds like you are talking through a fan or as if radio is keying and unkeying very rapidly while you hold key down checked mic and it is good. Checked radio again and found that when the receive would fade out that its receiving channel 28 on channel 27 so i guess its drifting off frequency on receive only. Still not sure if this would cause transmit to be choppy sometimes. Any help would be greatly appreciated. Thanks. Anyone know were i should start checking voltage from what I've read this is usually the cause of drifting off channel?
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Re: Connex 3300hp fading receive

Postby Rick » Monday 16th Apr 2007, 21:52

Check for bad soldering, as it sounds like a dry joint.

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Re: Connex 3300hp fading receive

Postby smokinjoe » Tuesday 17th Apr 2007, 3:42

Rick wrote:Check for bad soldering, as it sounds like a dry joint.

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Thanks for the reply Rick I've ran soldering iron across all of the ics and along receive chain starting with tr17 but still no change again Thanks for all your help its a good thing you do on this sight helping everyone out. This is a excellent radio forum lots of good information and nice friendly people from what Ive read so far. Thanks again to the forum for letting me join and every one else who helps make this forum what it is.
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Re: Connex 3300hp fading receive

Postby Rick » Tuesday 17th Apr 2007, 10:45

Check around the loop osc and carrier osc. I had one last year with a bad 10.695 xtal. Also check the RX switching transistor TR36 the collector should be about 8 to 8.5 volts in RX it maybe good idea to monitor the voltage over a period time.

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Postby SoCal392 » Wednesday 18th Apr 2007, 6:21

rick is right. It sounds like a bad 10.240 xtal. I experienced this recently with a connex 3300 and a galaxy 44
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Postby smokinjoe » Thursday 19th Apr 2007, 4:10

SoCal392 wrote:rick is right. It sounds like a bad 10.240 xtal. I experienced this recently with a connex 3300 and a galaxy 44
Thanks for every ones help Rick i checked voltage at tr36 and it was 8.7v '' SoCal392'' I also changed 10.240 xtal didn't have the right xtal to change 10.6975 xtal all i have is 10.695 xtal. radio is staying stable for now need to use for a while to see what happens. Thanks again for every ones help. I will let you all know if this cured it or not Thanks.
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Postby kc8mob » Thursday 19th Apr 2007, 15:32

Almost sounds like a junk regulator. Or somethings voltage has some ripple in it intermittently. That's if what you did already didn't fix it.
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Postby smokinjoe » Friday 20th Apr 2007, 4:14

kc8mob wrote:Almost sounds like a junk regulator. Or somethings voltage has some ripple in it intermittently. That's if what you did already didn't fix it.
Thanks ''kc8mob'' if it starts acting up again ill check the voltage on the regulator didn't think that would have any thing to do with it because the lights wouldn't dim when it was drifting off frequency . Thanks for your help.
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Postby kc8mob » Friday 20th Apr 2007, 18:03

Your PLL and all of that neat stuff run off of their own regulator. Not the device that supplies power to the audio and RF output stages.
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Postby smokinjoe » Saturday 21st Apr 2007, 5:03

kc8mob wrote:Your PLL and all of that neat stuff run off of their own regulator. Not the device that supplies power to the audio and RF output stages.
Thanks for every ones help i think the xtal may have fixed the problem radio is still stable so far. Like i said earlier this is a great forum and their is a lot of good information and good people helping each other out here i read up on new posts here daily and hopefully i will be able to help some one out in the near future my self. Thanks again to the forum and every one else who has helped me and others like me solve problems with their radios keep up the good work.
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