| Author |
Message |
    
Rodder54
Member
Username: Rodder54
Post Number: 51
Registered: 12-2001
| | Posted on Sunday, September 06, 2015 - 10:41 pm: | 
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you might have this on here i couldnt find any answers, so i have a president p400 i just got it,it transmits fine but even with a external speaker i hear nothing i do see the needle move i have a tone gen on any ideas thanks, |
Press_man
Advanced Member
Username: Press_man
Post Number: 879
Registered: 5-2008
| | Posted on Thursday, September 10, 2015 - 6:12 pm: |
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Tried an external speaker?
Do you have a schematic?
Sometimes a tuning will fix the problem.
Check the board for traces or components that look burnt.
Check for loose soldier joints.
Depending on the age of the radio it may need to be recapped.
Check IC 5/501 AF amp could be bad.
Might become a parts radio.
Catch Sonoma on here, he's good on tracing schematics.
73 Pressman
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Rodder54
Member
Username: Rodder54
Post Number: 52
Registered: 12-2001
| | Posted on Saturday, September 12, 2015 - 11:18 pm: |
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thanks ,did try external speaker, yes on schematic, did check soldier joints. it set for 17 years in its box in the attic until he gave it to me |
Tech237
Moderator
Username: Tech237
Post Number: 1837
Registered: 4-2004
| | Posted on Sunday, September 13, 2015 - 11:17 am: |
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Does it have the mic [plugged in??
Check on the schematic for the receive audio pins on the mic socket, and try carefully shorting the two pins. I usually use a straightened paperclip with female pis soldered to it.
Does it transmit audio and carrier?? If it does, the audio section is most likely OK, as it is used for both receive and transmit audio.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Jon666
Intermediate Member
Username: Jon666
Post Number: 497
Registered: 11-2003
| | Posted on Sunday, September 13, 2015 - 4:16 pm: |
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chances are if it sat that long the caps have dried out. try cleaning all the dials and switched.
clean the channel selector
what don't kill you makes you stronger
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Rodder54
Member
Username: Rodder54
Post Number: 56
Registered: 12-2001
| | Posted on Friday, June 23, 2017 - 10:02 pm: |
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it transmits good and the receive is just quiet with external speaker or not i see the needle move if i use a different radio i cleaned the volume ,rf gain ,squelch anything else to try ? |
Tech237
Moderator
Username: Tech237
Post Number: 1874
Registered: 4-2004
| | Posted on Monday, June 26, 2017 - 2:14 pm: |
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Check the schematic and see if two pins on the mic plug need to be shorted for receive audio. If they do check the mic cable for a broken lead.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Rodder54
Member
Username: Rodder54
Post Number: 57
Registered: 12-2001
| | Posted on Tuesday, June 27, 2017 - 8:08 pm: |
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thanks i did that first and tried different mics too |
Rodder54
Member
Username: Rodder54
Post Number: 58
Registered: 12-2001
| | Posted on Tuesday, June 27, 2017 - 8:18 pm: |
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i put a signal generator on it you can see it ,just no sound with external speaker i tried 2 and the stock speaker is there something else that can cause this |
Tech237
Moderator
Username: Tech237
Post Number: 1875
Registered: 4-2004
| | Posted on Wednesday, June 28, 2017 - 8:12 am: |
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Check the external speaker jack. IT has an inbuilt switch that disconnects the internal speaker when a plug is inserted, It's possible that the switch is fatigues and stays in the open position.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Rodder54
Member
Username: Rodder54
Post Number: 59
Registered: 12-2001
| | Posted on Saturday, July 01, 2017 - 8:50 am: |
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thanks still not it. |
Tech237
Moderator
Username: Tech237
Post Number: 1876
Registered: 4-2004
| | Posted on Monday, July 03, 2017 - 3:21 pm: |
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OK, if we get audio on the transmitted signal,but nothing out on receive using internal or external speakers, I would assume we get audio on the PA (not sure if this radio has the PA option), about the only thing left would be a glitch in the TX/RX switching system
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Rodder54
Member
Username: Rodder54
Post Number: 60
Registered: 12-2001
| | Posted on Wednesday, July 05, 2017 - 8:54 pm: |
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it has a pa but it dont work i was wondering if that had anything to do with it. i also have a navaho 440 i loaned a friend and lightning struck close and it lost receive too . the uniden has just been put up for years the guy i got it from said it worked great when he put it up.i cant find anything to the eye bad on ether radio i also tried the head phone jack on both radios. .thanks for the help .not sure what else to try |
Tech237
Moderator
Username: Tech237
Post Number: 1877
Registered: 4-2004
| | Posted on Wednesday, July 12, 2017 - 4:52 pm: |
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OK if the PA doesn't work,we are looking at either switching system for the audio is stuck in TX mode or issues with the RX audio amp stages. I"ll try to locate a diagram and take a better look
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Rodder54
Member
Username: Rodder54
Post Number: 61
Registered: 12-2001
| | Posted on Thursday, July 13, 2017 - 11:25 pm: |
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ok thanks .it does show the movement on the meter with no sound. |
Tech237
Moderator
Username: Tech237
Post Number: 1879
Registered: 4-2004
| | Posted on Monday, July 17, 2017 - 8:24 am: |
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Can still be the audio switching. The meter reads from the RF side of things.
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Rodder54
Member
Username: Rodder54
Post Number: 62
Registered: 12-2001
| | Posted on Monday, July 17, 2017 - 10:33 pm: |
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ok thanks where is that,lol |
Tech237
Moderator
Username: Tech237
Post Number: 1880
Registered: 4-2004
| | Posted on Friday, July 21, 2017 - 10:30 am: |
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From the block diagram I found (http://www.cbradio.nl/president/Service_Manual_President_Washington_MB8719_Homer_ENG.pdf) it appears switching is handled by T27 and T45
Tech237
N7AUS
God made me an athiest, who are you to question his wisdom?
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Rodder54
Member
Username: Rodder54
Post Number: 64
Registered: 12-2001
| | Posted on Thursday, January 11, 2018 - 9:31 pm: |
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i found what it was i was changing the caps and one had a bad solder join didn't see until i pulled it out ,thanks for the help |
