| Author |
Message |
    
Af579
Member
Username: Af579
Post Number: 70
Registered: 6-2003
| | Posted on Friday, December 29, 2006 - 10:19 pm: | 
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ok lost all tx audio but rx audio ok. !st thing that came to mind was ta7222ap it was bad so replaced. now tx audio on ssb only no am tx audio. rx still ok all modes.
Any ideas?
From The Sunshine State Central
Af579
CEF 472
HAM 185
|
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2353
Registered: 9-2004
| | Posted on Friday, December 29, 2006 - 11:30 pm: |
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replace the AM power regulator.
if its the MB8719 model, then it should be TR41 on the right rear side of the PC board.
stock is either a 2SC1419 or a C1135.
replace it with a 2N6487 or if you cant find one of those, use an NTE152.
be sure to use a new insulator, use heat sink compound, and check with an ohmmeter that the tab of the new transistor is not making electrical contact with the chassis.
if this is the old style madison with the UPD858 chip in it; replace all the 2SC1419's with the 2N6487 or NTE152.
good luck,
matt |
Af579
Member
Username: Af579
Post Number: 71
Registered: 6-2003
| | Posted on Saturday, December 30, 2006 - 5:38 pm: |
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Thanks kid!
it has the c1137. thats 2sc1137 correct?
Rich
From The Sunshine State Central
Af579
CEF 472
HAM 185
|
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2355
Registered: 9-2004
| | Posted on Sunday, December 31, 2006 - 1:15 am: |
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i have never heard of a 2SC1137 being in one of these, but that doesnt mean they havent used them.
i cant find any info online about that transistor.
which madison do you have?
the one with the MB8719 PLL in it, or the one with the UPD858 PLL in it?
if that doesnt make sense to you, then does it say Uniden or president on it, and does it have a digital clock or an analog clock on it?
matt |
Af579
Member
Username: Af579
Post Number: 72
Registered: 6-2003
| | Posted on Sunday, December 31, 2006 - 11:56 am: |
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Kid I got it. just can't find either of the c1137, 2n6487, nte152 in my normal parts catalog place in california.
Thanks for the help!
rich
From The Sunshine State Central
Af579
CEF 472
HAM 185
|
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2358
Registered: 9-2004
| | Posted on Tuesday, January 02, 2007 - 6:42 pm: |
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check the auction sites.
matt |
