| Author |
Message |
    
Hackenbush
New member
Username: Hackenbush
Post Number: 1
Registered: 12-2007
| | Posted on Friday, November 28, 2008 - 11:35 pm: | 
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Uniden Grant XL Philly, PB-208AD, Radio was working great when i decided to check the bias.( DUMMY ) I pulled the purple wire off TP8 and put a volt meter between the purple wire and the post on board. I must have touched something because i seen smoke (i am not american indian). Now there is no transmit carrier on AM or Sideband. Transmit lite lites up when i key mike but no carrier. Nothing out the watt meter through antenna. I can here audio when i plug headphones into extension speaker and key the mic. There is audio through the PA. Everything else works great. Stock mic. Any help on what i should check. HB |
Hackenbush
New member
Username: Hackenbush
Post Number: 2
Registered: 12-2007
| | Posted on Wednesday, December 03, 2008 - 11:34 am: |
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Changed the Final. Still no transmit. When I key the mic the meter needle drops backwards. Also when it started smoking it looked like it was coming from the front of the board. Anybody!! |
Hackenbush
New member
Username: Hackenbush
Post Number: 3
Registered: 12-2007
| | Posted on Thursday, December 04, 2008 - 2:01 pm: |
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Replaced driver and nte152, Q37,Q39 still no transmit? Checked voltages on ic4 8.17-12.21-8.17-0-12.21-8.17-0-and pin 8 is 5.53 when transmitting. How do i know if ic4 is any good? On my 148 pin 8 is 8.77 on transmit? Any HELP??? |
Superbad
New member
Username: Superbad
Post Number: 4
Registered: 12-2008
| | Posted on Friday, December 12, 2008 - 9:24 am: |
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The one I inherited is doing the same thing. But after I tap on it a lil & twist a couple of knobs it starts back. But this is an old Radio. Going to get in it this weekend & see whats going on. But mine didn't smoke. ^^^^^ < Those are tee-pe's LOL J/K |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 4435
Registered: 7-2004
| | Posted on Friday, December 12, 2008 - 9:14 pm: |
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have you looked to see what smoked? if you got smoke, you should be able to find discoloration at the very least on SOMETHING, or melted wax or other coating, or even the wire lead(leg) to a transistor, cap, diode, etc with a sign of excessive heat. |
Hackenbush
New member
Username: Hackenbush
Post Number: 4
Registered: 12-2007
| | Posted on Monday, December 15, 2008 - 11:10 pm: |
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Pat thanks for the help. I looked for anything i thought was burnt and replaced it. Everything seemed to check out ok. I replaced ic4 and that wasnt it. Is there any spot i can start at and check along those lines for TX? I really dont know where to look next. Everthing else works great, just no transmit to the watt meter? Thanks, HB |
Tech858
Moderator
Username: Tech858
Post Number: 199
Registered: 10-2007
| | Posted on Tuesday, December 16, 2008 - 3:27 pm: |
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Sounds like you smoked the carrier oscilator transistor , not sure of the component number on the board but should be at the front of board somewhere near the 10.240 crystal .
Tech858/Jim
CEF#0858 ~ CEF HAM#0230
CVC#0116 ~ MM0TXO
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Hackenbush
New member
Username: Hackenbush
Post Number: 5
Registered: 12-2007
| | Posted on Thursday, December 18, 2008 - 5:27 pm: |
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Tech858 thanks for the help. I changed Q32. I think thats the carrier oscillator transistor. Not sure. Still no transmit to the watt meter. Everything else works great. Voltage at TP 7 & 8 are 0.23 on receive and 0.09 on transmit AM and SSB. I know that is wrong. Any help. Thanks, hb |
Tech858
Moderator
Username: Tech858
Post Number: 200
Registered: 10-2007
| | Posted on Thursday, December 18, 2008 - 6:14 pm: |
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OK check out the TX mixer and buffer stages to see if anything burnt out looking there .
Tech858/Jim
CEF#0858 ~ CEF HAM#0230
CVC#0116 ~ MM0TXO
|
Hackenbush
New member
Username: Hackenbush
Post Number: 6
Registered: 12-2007
| | Posted on Monday, December 22, 2008 - 7:27 pm: |
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Tech858 thanks for all the help.I checked tx mixer and buffer stages. Could not find anything bad? Voltage at TP7+8 are 0.23 on receive and 0.09 on transmit? Somebody said my mode switch could be bad? Any other ideas? Thanks, HB |
Hackenbush
New member
Username: Hackenbush
Post Number: 7
Registered: 12-2007
| | Posted on Thursday, January 29, 2009 - 6:31 pm: |
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Replaced mode switch. Still no TX? No voltage at TP7 and TP8 - 0.11 volts? Anybody??? |
