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Message |
    
Missie
New member
Username: Missie
Post Number: 5
Registered: 10-2006
| | Posted on Sunday, October 22, 2006 - 10:48 pm: | 
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I have a 29 with very little volume, and the sqelch dose not work speaker good, volume control good,
VR1 turned up,
replaced R31 any ideas??? |
Pogo12
Member
Username: Pogo12
Post Number: 93
Registered: 3-2005
| | Posted on Monday, October 23, 2006 - 1:29 pm: |
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Check your audio chip(TA72222AP)IC4.The squelch circuit is connected to this chip(IC4)so it may be the problem.Check the small circuit board that is connected to the mic plug.Because the mike being pluged in alot causes these connections to break loose.The second sugestion has nothing to do with the squelch but should be checked anyway.Also if you see a small .01 caqpacitor connected from the IC4 to ground remove it.This capacitor tends to cause a buzz in the radio.If you need the pin out for IC4 let me know. |
Missie
New member
Username: Missie
Post Number: 9
Registered: 10-2006
| | Posted on Saturday, October 28, 2006 - 11:12 am: |
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pogo12 I changed the chip and no change any other ideas? thanks |
Pogo12
Intermediate Member
Username: Pogo12
Post Number: 101
Registered: 3-2005
| | Posted on Monday, October 30, 2006 - 5:45 pm: |
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Have you checked your rf gain to see if signal is getting through properly?Sounds like it could be a squelch circuit problem.Its not switching properly .Tr-12/tr11/tr13 are part of your squelch amp circuit in that order from the antenna.It may not be getting the rec.voltage it needs to make these transistors work.If you had a signal checker you could trace your squelch by checking for if the squelch is working at Your collector and base of TR13 then TR11 and then TR12 which is the final squelch amp before the agc detector towards the antenna.You can also use a voltage meter and rotate the squelch knob to see if the voltages change at each transistor.When you find one that dosent change anything you have found your problem. The squelch range is set by vr3 in the radio and of course the knob on front of the radio.Try adjusting it from open to closed to see if the squelch works anywhere. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1966
Registered: 1-2005
| | Posted on Wednesday, November 01, 2006 - 11:56 am: |
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Does your meter indicate signals present?
Have you done a mic check?
Does your PA work?
Do you have output? Carrier only or carrier and modulation? |
Missie
Junior Member
Username: Missie
Post Number: 11
Registered: 10-2006
| | Posted on Wednesday, November 01, 2006 - 10:13 pm: |
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Hot wire the radio works perfect on transmit 2watts out swings at 17 clear as a bell talk back works nice and loud. every one says they wish there's sounded that good. but they have to call me on the phone I can't here them. the problem is very little volume and recieve turned up all the way you can't here. |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1981
Registered: 1-2005
| | Posted on Saturday, November 04, 2006 - 4:42 pm: |
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Well the first thing that comes to mind would be a bad audio output transistor or IC. Could be called the audio chip but you say you replaced it. Since your modulation seems to be good and PA works (does PA work?)I doubt that it is the audio transistor or chip.
Are you positive that the mic is wired correctly in the mic housing, in the mic plug, the mic plug socket in the radio and the mic socket wires to the board?. Checked and confirmed that none of the solder connections have broke loose or touching others to ground out?
Have you tried an external speaker and checked the connections to the external speaker jack inside the radio and the wires leading from the jack to the board and no shorts or grounds caused by bare wires? Try a different antenna?
Right now thw only thing I can think of is 2 more things. Have you used this radio for awhile or did you just get it used recently in the condition it's in? Has the radio been very close to another radio running an amplifier. Its a common truck driver problem that accurs in truck stops a lot when everyone is running high watts next to each other, also if your nieghbors runs a big amp with his beam pointing at you.
Cb's have a protection diode in them that protects the reciever from extremely high front end overload. You may need to go to SAMs photfacts to find the part you would look for. Other than that your reciever might be in need of a major alignment! I just do not know what else it could be. Good Luck
Kenny |
Pogo12
Intermediate Member
Username: Pogo12
Post Number: 102
Registered: 3-2005
| | Posted on Saturday, November 04, 2006 - 8:53 pm: |
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when you turn your squelch all the way up and turn VR3 either direction does the squelch silence the speaker at all?VR3 is the squelch alignment for the 29LTD |
Missie
Junior Member
Username: Missie
Post Number: 12
Registered: 10-2006
| | Posted on Saturday, November 04, 2006 - 11:30 pm: |
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hot wire this radio was working great i have had it for a while i built it about a year ago.I have tryed every thing that you said exsept for the diod I didn't know there was one for the reicve I new about the one for the power. do you know which one it is? |
Missie
Junior Member
Username: Missie
Post Number: 13
Registered: 10-2006
| | Posted on Saturday, November 04, 2006 - 11:34 pm: |
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pogo 12 with the squelch all the way up and adjsting VR3 it makes know difference. I still have to ck the transistors I have goten to that yet. thanks |
Hotwire
Senior Member
Username: Hotwire
Post Number: 1983
Registered: 1-2005
| | Posted on Sunday, November 05, 2006 - 1:51 pm: |
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No Bruce I sure don't buddy! If you was in my neck of the woods I would try yo help ya more by taking a look at it myself. It might be about time to visit a tech if the radio is worth spending more money on to you. I really hope you get it working and keep us posted on your findings OK? I would love to know whats wrong with it. Good luck man, its frustrating I know!
Kenny
CEF491 |
Pogo12
Intermediate Member
Username: Pogo12
Post Number: 112
Registered: 3-2005
| | Posted on Saturday, November 11, 2006 - 1:25 pm: |
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I Have a funny feeling.Check C35 and C36.If these caps are shorted it would pull down the signal.Also check C30 and C147.Check for 8.5 volts at the junction of R42 and R43.It should drop out to 0 volts on transmit.Check R41 for 7.8volts.All of this is part of the squelch circuit.While its true that most falures are due to bad main parts such as transistors and ICs you still have to suspect small attached parts as they do go out from time to time. |
Mopar2ya
New member
Username: Mopar2ya
Post Number: 3
Registered: 2-2004
| | Posted on Sunday, November 12, 2006 - 1:53 pm: |
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I am sure you would have tested this, but I have gone way overboard before trying something simple so I will mention it anyway.
Have you plugged an external speaker in to make sure the jack isn't shorted? |
Mopar2ya
New member
Username: Mopar2ya
Post Number: 4
Registered: 2-2004
| | Posted on Sunday, November 12, 2006 - 10:23 pm: |
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Sorry. Should have read Hotwire's post more carefully..... |
Missie
Junior Member
Username: Missie
Post Number: 15
Registered: 10-2006
| | Posted on Monday, November 27, 2006 - 5:27 pm: |
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pogo 12 I checked the caps and transisters and come up all good I told you that VR3 didn't make any diffrence at all but I never ck VR1 it dosn't work ether I'am about ready to trash this thing it's driving me crazy!!!!!!!! thanks for your help though |
