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Message |
    
Spugeddy
New member
Username: Spugeddy
Post Number: 1
Registered: 10-2015
| | Posted on Sunday, October 18, 2015 - 5:01 pm: | 
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Hello everybody. I've had a Magnum S-9 for quite a few years now and never had a problem with it. In fact I've gotten many compliments. After sitting idle for 2-3 years I decided to blow off the dust, spray some contact cleaner in the pots and fire it up again. (in my home as a base not in my car) Radio is connected to a Pyramid 35 amp power supply, Solorcon A99 antenna, Astatic EchoMax 200 mic. SWR is approx 1.15:1. Yesterday I noticed that while I was talking my SWR started to go really high (up in the red) while in the middle of a keydown. With a quick glance up to the radio, I noticed that the frequency counter was all the way down in the 24mhz band. The Band dial (A,B,C,D,E, etc) was still on the C band. Changing the Band dial did nothing. The radio just kept on scanning the frequencies. Turning the unit off then back on didn't help either. It seems like I had the shut the radio down and let it cool before it would act right again.
Any ideas? |
Tech237
Moderator
Username: Tech237
Post Number: 1840
Registered: 4-2004
| | Posted on Tuesday, October 20, 2015 - 11:31 am: |
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Couple of questions, to hrlp us troubleshoot this.
1)Could the station you were talking to still hear you when this happened? If they could, then the radio was not actually changing frequencies.
2) When scanning, I assume a signal on the displayed frequency doesnt stop the scan, or does it?
3) If left in straight receive mode, does the same thing happen after any period of time??
I suspect from your brief description, we may have a dry joint, a short of a bad capacitor, but the question is in what circuit, hence my questions.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Spugeddy
New member
Username: Spugeddy
Post Number: 2
Registered: 10-2015
| | Posted on Tuesday, October 20, 2015 - 10:13 pm: |
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Thanks for the reply Tech
1. the station i was talking to lost my transmit when it happened. I only realized something was happening because; as I was keyed down and talking, I noticed my SWR meter was going up, up, up and into the red. I looked up and noticed the freq. counter in a "runaway" mode just scanning in the 24mhz band. On a couple of occasions, it went from 24mhz into the 27mhz in a matter of a few seconds, but obviously not in any kind of order. It's more like jumps.
2. when I unkeyed the counter continued to scan and i could obviously hear nothing but normal noise, and nobody modulating.
3. once it starts the scanning thing, Yes. It will start its own scan sporadically. When it does it, I feel the bottom and back of the radio and don't feel enough heat to be concerned.
Again, thank you for the help so far.
Jim |
Tech237
Moderator
Username: Tech237
Post Number: 1841
Registered: 4-2004
| | Posted on Friday, October 23, 2015 - 1:34 pm: |
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OK. Sounding like it is the actual scanning/frequency circuits are our problem then. Check for bad solder joints, slightly distorted electrolytic capacitors in those areas.
Next time it does it, try aiming a small amount of cooling air at those areas of the circuit board to see if it stops.
Hopefully, someone with more knowledge of this radio will jump in with better information.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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