HFU HF Underground
General Category => General Radio Discussion => Topic started by: Nella F. on July 14, 2016, 1811 UTC
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So this morning the squelch is in constant 'hiss' mode. Turning the squelch all the way "clockwise" (owners manual, p. 25) makes no difference. Occasionally scans as normal but after 1st. xmit. it picks up & xmit. ends back to 'hiss'. My tech. expertise limited to tubes & Bill Cheek's Pro-2004,5,6 mod's newsletter.
Other than resetting or breaking out screwdrivers & poking about here & there I got no clue. Maybe somebody's got experience with this. Still got my Pro-43, works just fine.
Comments?
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so the squelch works but the squelch close time after receiving a transmission is slow ?
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Nah, I don't understand your "?".
The radio 'hisses" no matter how far I turn the squelch to try & eliminate it.
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Everything in the world that is wrong is probably related to bad caps. I would start there.
+-RH
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Is there a monitor function that overrides the squelch?
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Edit : I had originally posted info about the 2004, then I saw you said pro94 , but the squelch control may just a 10k potentiometer. I could not find the parts list for your radio but it's likely similar.
The wiper inside the housing may have some corrosion that is a common problem. Also it's possible it's snapped off and there is no contact with the resistor of course. Try exercising it by rotating it like a hundred times and this should clean the track . You can do this with the radio on and if nothing suddenly happens, then put an ohm meter ( multimeter) across the pt terminals with the radio off and as you rotate it check for changes in resistance. Should be maybe 5 or 10 ohms to 10000 range. You could bridge the terms with a 2 or 3 k ohm resistor and see if that shuts it up.
If that works and you still can't get the control working try Deoxit or gasp_ WD40.
If you cannot get results with these simple things, it's a different world beyond that. Printed circuit radios are nerve wracking , you may want to consider recycling.
Could be a cap , like Redhat suggested. Not often this is a problem with caps in radios under 50years old, although I have heard of cheap ones already blowing out in flat screens so you never know.
Caps can be tricky to test in circuit. A bad one will be open or shorted, but it usually open , although Caveat: they may read ok on a mulitmeter in situ. I didn't look at the schematic but most likely in the immediate area of the pt if the radio works correctly otherwise , don't venture outside of the immediate components serving that circuit. If you do remove anything, use a low wattage pencil and you really need some specialized tools .
Good luck '
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Edit : I had originally posted info about the 2004, then I saw you said pro94 , but the squelch control may just a 10k potentiometer. I could not find the parts list for your radio but it's likely similar.
The wiper inside the housing may have some corrosion that is a common problem. Also it's possible it's snapped off and there is no contact with the resistor of course. Try exercising it by rotating it like a hundred times and this should clean the track . You can do this with the radio on and if nothing suddenly happens, then put an ohm meter ( multimeter) across the pt terminals with the radio off and as you rotate it check for changes in resistance. Should be maybe 5 or 10 ohms to 10000 range. You could bridge the terms with a 2 or 3 k ohm resistor and see if that shuts it up.
If that works and you still can't get the control working try Deoxit or gasp_ WD40.
If you cannot get results with these simple things, it's a different world beyond that. Printed circuit radios are nerve wracking , you may want to consider recycling.
Could be a cap , like Redhat suggested. Not often this is a problem with caps in radios under 50years old, although I have heard of cheap ones already blowing out in flat screens so you never know.
Caps can be tricky to test in circuit. A bad one will be open or shorted, but it usually open , although Caveat: they may read ok on a mulitmeter in situ. I didn't look at the schematic but most likely in the immediate area of the pt if the radio works correctly otherwise , don't venture outside of the immediate components serving that circuit. If you do remove anything, use a low wattage pencil and you really need some specialized tools .
Good luck '
I did do the squelch rotation a bunch a day or two after the problem first appeared, don't know if that did it but problem disappeared shortly after...not paying too close attention to time these days. Here in Oak Harbor there be salt in the air so corrosion makes sense. Guess I'll break out the syringe & alkeyhall & really give it a good twist. Your other suggestions be a bit above my pay grade but thanks for your comments.
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Ok cool - it happens when isn't used for awhile to any radio.
Glad you got it