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#11
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![]() "Honest John" wrote in message ... Component failure may have cause the IF freq. to shift off of the correct freq. HJ Thanks Honest John, Well, the scanner is still displaying, responding to calls, and giving low audible output. But if your theory is correct, I'm screwed:-(...I won't give up hope...I am going to try the pot and hope like heck that is all it is. I would fare better off buying a new one if I had the problem you described. Thanks for the input and let's hope for non-failure of component/s:-) regards, Allen |
#12
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On Wed, 01 Mar 2006 02:28:26 GMT, "Allen Crawford"
wrote: I would fare better off buying a new one Try hanging a 47k resistor between the high end and the center pin of the pot and keep the pot about at the center. It's not a fix, but if it works a little, you know the pot is shot (open on the high end). You wouldn't be happy spending $15 for a pot to discover that it's not the pot that's the problem. |
#13
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Just wondering, if you tried to do a re-set of the radio? I doubt that
would do anything, but it might not hurt. -SMTP "Allen Crawford" wrote in message ... I recently purchased a pro97 scanner in near new condition over the internet through ebay. The item was listed as having very low audio such as one has to place the speaker next to his ear to hear the broadcast so I took a chance and bought it for 45 dollars. I got it in yesterday and it is totally new! packaging, all accessories, books and not a scratch on it. Well. I unpack it and install freshly charged (new) batteries and I go to playing with it..first..a weather channel..sure enough, very low volume even when cranked to the fullest it is still at the same volume level. I went ahead and took out the four back cover screws and examined the area where the volume pot is soldered and took some readings. center tap is about 2.1kohm and 200 k ohm on the non grounded side. (this is without power applied) in the area of the volume/squelch pot, are 3 tiny pots and 3 test points...(this is all from memory as the scanner is closed up now). I was hoping for a misplaced speaker magnet or something simpler and the circuits are ungodly miniature and even the audio amp chip is about the size of an op amp on most regular size circuits. The doggone thing is so new looking, that it may be swapped with a newer one from radio shack (by swapping backplates) but I don't dare attempt the dishonest. Anyway, any suggestions to resolve my dillemma...could it be possible that I have a defective volume pot? No amount of regulation seems to affect the audio at all. The channel beep come through loud and clear but it seems that either the preamp from the radio is set too low or the pot is defective/soldered wrong. Of course, the possibility of a bad IC has crossed my mind as well. Any suggestions? No warranty so all I have is either a repairman or my good wits and some knowledge to help correct the problem. Btw, the sqelch seems to work OK. Your input would be greally appreciated, Allen |
#14
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![]() "Mr. Man with the Master Plan" wrote in message ... Just wondering, if you tried to do a re-set of the radio? I doubt that would do anything, but it might not hurt. -SMTP Well shoot fire, I am receptive to anything right about now...I figure that the worst it could do is delate all the pre-sets...but what the hay...I'll give it a whirl! Gonna have to consult the manual to find it's where-abouts! Cheers!, Allen "Allen Crawford" wrote in message ... I recently purchased a pro97 scanner in near new condition over the internet through ebay. The item was listed as having very low audio such as one has to place the speaker next to his ear to hear the broadcast so I took a chance and bought it for 45 dollars. I got it in yesterday and it is totally new! packaging, all accessories, books and not a scratch on it. Well. I unpack it and install freshly charged (new) batteries and I go to playing with it..first..a weather channel..sure enough, very low volume even when cranked to the fullest it is still at the same volume level. I went ahead and took out the four back cover screws and examined the area where the volume pot is soldered and took some readings. center tap is about 2.1kohm and 200 k ohm on the non grounded side. (this is without power applied) in the area of the volume/squelch pot, are 3 tiny pots and 3 test points...(this is all from memory as the scanner is closed up now). I was hoping for a misplaced speaker magnet or something simpler and the circuits are ungodly miniature and even the audio amp chip is about the size of an op amp on most regular size circuits. The doggone thing is so new looking, that it may be swapped with a newer one from radio shack (by swapping backplates) but I don't dare attempt the dishonest. Anyway, any suggestions to resolve my dillemma...could it be possible that I have a defective volume pot? No amount of regulation seems to affect the audio at all. The channel beep come through loud and clear but it seems that either the preamp from the radio is set too low or the pot is defective/soldered wrong. Of course, the possibility of a bad IC has crossed my mind as well. Any suggestions? No warranty so all I have is either a repairman or my good wits and some knowledge to help correct the problem. Btw, the sqelch seems to work OK. Your input would be greally appreciated, Allen |
#15
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![]() "Allen Crawford" wrote in message ... "Mr. Man with the Master Plan" wrote in message ... Just wondering, if you tried to do a re-set of the radio? I doubt that would do anything, but it might not hurt. -SMTP Well shoot fire, I am receptive to anything right about now...I figure that the worst it could do is delate all the pre-sets...but what the hay...I'll give it a whirl! Gonna have to consult the manual to find it's where-abouts! Cheers!, Allen "Allen Crawford" wrote in message ... I recently purchased a pro97 scanner in near new condition over the internet through ebay. The item was listed as having very low audio such as one has to place the speaker next to his ear to hear the broadcast so I took a chance and bought it for 45 dollars. I got it in yesterday and it is totally new! packaging, all accessories, books and not a scratch on it. Well. I unpack it and install freshly charged (new) batteries and I go to playing with it..first..a weather channel..sure enough, very low volume even when cranked to the fullest it is still at the same volume level. I went ahead and took out the four back cover screws and examined the area where the volume pot is soldered and took some readings. center tap is about 2.1kohm and 200 k ohm on the non grounded side. (this is without power applied) in the area of the volume/squelch pot, are 3 tiny pots and 3 test points...(this is all from memory as the scanner is closed up now). I was hoping for a misplaced speaker magnet or something simpler and the circuits are ungodly miniature and even the audio amp chip is about the size of an op amp on most regular size circuits. The doggone thing is so new looking, that it may be swapped with a newer one from radio shack (by swapping backplates) but I don't dare attempt the dishonest. Anyway, any suggestions to resolve my dillemma...could it be possible that I have a defective volume pot? No amount of regulation seems to affect the audio at all. The channel beep come through loud and clear but it seems that either the preamp from the radio is set too low or the pot is defective/soldered wrong. Of course, the possibility of a bad IC has crossed my mind as well. Any suggestions? No warranty so all I have is either a repairman or my good wits and some knowledge to help correct the problem. Btw, the sqelch seems to work OK. Your input would be greally appreciated, Allen OK..there is not hard reset button on this one, like older models. You initialize by going through a sequence of turning off/then on the scanner. While the splash screen reads multi system trunking...etc. (you usually have 5 secs) then you press 0 1 enter and wait about 5 seconds as it tells you that it is initializing. You lose all your presets but mine was set by RS anyway. No help though...still just as quiet as before...He! he! sorta reminds me of the day when I got my first crystal set:-) Thanks all for the suggestions, regards to all, Allen |
#16
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On Tue, 28 Feb 2006 23:56:58 GMT, "Allen Crawford"
wrote: I recently purchased a pro97 scanner in near new condition over the internet through ebay. The item was listed as having very low audio such as one has to place the speaker next to his ear to hear the broadcast so I took a chance and bought it for 45 dollars. I got it in yesterday and it is totally new! packaging, all accessories, books and not a scratch on it. Well. I unpack it and install freshly charged (new) batteries and I go to playing with it..first..a weather channel..sure enough, very low volume even when cranked to the fullest it is still at the same volume level. I went ahead and took out the four back cover screws and examined the area where the volume pot is soldered and took some readings. center tap is about 2.1kohm and 200 k ohm on the non grounded side. (this is without power applied) in the area of the volume/squelch pot, are 3 tiny pots and 3 test points...(this is all from memory as the scanner is closed up now). I was hoping for a misplaced speaker magnet or something simpler and the circuits are ungodly miniature and even the audio amp chip is about the size of an op amp on most regular size circuits. The doggone thing is so new looking, that it may be swapped with a newer one from radio shack (by swapping backplates) but I don't dare attempt the dishonest. Anyway, any suggestions to resolve my dillemma...could it be possible that I have a defective volume pot? No amount of regulation seems to affect the audio at all. The channel beep come through loud and clear but it seems that either the preamp from the radio is set too low or the pot is defective/soldered wrong. Of course, the possibility of a bad IC has crossed my mind as well. Any suggestions? No warranty so all I have is either a repairman or my good wits and some knowledge to help correct the problem. Btw, the sqelch seems to work OK. Your input would be greally appreciated, Allen Allen, I had a PRO-96 that had the *exact* same problem... I'm not sure how similar it is to the PRO-97, so the following may or may not be of any use... but might be worth a try, or may give you some ideas... Have a look at the picture at: http://www.ninemoons.com/~daf/images/PRO-96.jpg After trying all the obvious stuff, I found that very gently pushing down on the edge of the circuit board (with a non-metallic object :-) in the area outlined in red that the volome would increase tremendously. It was quite touchy, and seemed to be fairly localized to that general area. Volume would always return to it's previously "barely audible" state when pressure was released. I suspected a micro-crack in a solder joint or possibly one of the "plated-through" holes. A "cold" solder joint was another possibility... I removed the board and inspected both sides very carefully in that area with the highest power magnifier I had on hand (an eyepiece from a microscope...:-) Visual inspection didn't reveal anything, so I put the board back in and tried it again with the exact same results. This went on about 4 times until I finally got disgusted and drug out my trusty soldering iron! Having done a lot of bench work, I have a soldering iron with a tip about the size of a ball-point pin. I wouldn't recommend doing this with anything bigger, as it is very easy to overheat these SMT components. Using some high power reading glasses, I very briefly heated each of the solder joints "to melting" in the general area outlined in red, using no extra solder. (Very easy to use too much on these tiny pads!) I did add very minute amounts of solder to some of the plated-through holes until I could tell from both sides they were "soldered-through" After putting things back together - VOILA! Normal sound levels! The final test was when I could get no changes in the (now normal) volume by pushing down in area that had been so touchy before. Hope this helps... -Dan ------ Disclaimer! I'm NOT responsible if you muck things up worse!! |
#17
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![]() "Dan" wrote in message ... On Tue, 28 Feb 2006 23:56:58 GMT, "Allen Crawford" wrote: I recently purchased a pro97 scanner in near new condition over the internet through ebay. The item was listed as having very low audio such as one has to place the speaker next to his ear to hear the broadcast so I took a chance and bought it for 45 dollars. I got it in yesterday and it is totally new! packaging, all accessories, books and not a scratch on it. Well. I unpack it and install freshly charged (new) batteries and I go to playing with it..first..a weather channel..sure enough, very low volume even when cranked to the fullest it is still at the same volume level. I went ahead and took out the four back cover screws and examined the area where the volume pot is soldered and took some readings. center tap is about 2.1kohm and 200 k ohm on the non grounded side. (this is without power applied) in the area of the volume/squelch pot, are 3 tiny pots and 3 test points...(this is all from memory as the scanner is closed up now). I was hoping for a misplaced speaker magnet or something simpler and the circuits are ungodly miniature and even the audio amp chip is about the size of an op amp on most regular size circuits. The doggone thing is so new looking, that it may be swapped with a newer one from radio shack (by swapping backplates) but I don't dare attempt the dishonest. Anyway, any suggestions to resolve my dillemma...could it be possible that I have a defective volume pot? No amount of regulation seems to affect the audio at all. The channel beep come through loud and clear but it seems that either the preamp from the radio is set too low or the pot is defective/soldered wrong. Of course, the possibility of a bad IC has crossed my mind as well. Any suggestions? No warranty so all I have is either a repairman or my good wits and some knowledge to help correct the problem. Btw, the sqelch seems to work OK. Your input would be greally appreciated, Allen Allen, I had a PRO-96 that had the *exact* same problem... I'm not sure how similar it is to the PRO-97, so the following may or may not be of any use... but might be worth a try, or may give you some ideas... Have a look at the picture at: http://www.ninemoons.com/~daf/images/PRO-96.jpg After trying all the obvious stuff, I found that very gently pushing down on the edge of the circuit board (with a non-metallic object :-) in the area outlined in red that the volome would increase tremendously. It was quite touchy, and seemed to be fairly localized to that general area. Volume would always return to it's previously "barely audible" state when pressure was released. I suspected a micro-crack in a solder joint or possibly one of the "plated-through" holes. A "cold" solder joint was another possibility... I removed the board and inspected both sides very carefully in that area with the highest power magnifier I had on hand (an eyepiece from a microscope...:-) Visual inspection didn't reveal anything, so I put the board back in and tried it again with the exact same results. This went on about 4 times until I finally got disgusted and drug out my trusty soldering iron! Having done a lot of bench work, I have a soldering iron with a tip about the size of a ball-point pin. I wouldn't recommend doing this with anything bigger, as it is very easy to overheat these SMT components. Using some high power reading glasses, I very briefly heated each of the solder joints "to melting" in the general area outlined in red, using no extra solder. (Very easy to use too much on these tiny pads!) I did add very minute amounts of solder to some of the plated-through holes until I could tell from both sides they were "soldered-through" After putting things back together - VOILA! Normal sound levels! The final test was when I could get no changes in the (now normal) volume by pushing down in area that had been so touchy before. Hope this helps... -Dan ------ Disclaimer! I'm NOT responsible if you muck things up worse!! Thanks Dan, I have since got a pro2051 with missing speaker and ribbon cables and which I since managed to revive. My wife has since kidnapped the 2051 and this gives me some incentive to return to the PRO 97 project. Thanks for the tidbit of NFO and I will report back if things get better. FYI...I have already changed out 2 caps with the same capacitance but with a slightly higher volt rating. I was about to vye for a replacement pot. (squelch/vol) Your solution does sound compelling...I'll investigate. Thanks again and regards, Allen |
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