| Author |
Message |
    
Buck
| | Posted on Tuesday, February 04, 2003 - 3:26 am: | 
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I found a 148GTL at work that is in mint condition. The covers dont look like they have ever been off and it isnt hacked up...Everything works great except for the transmit.It dosent have a carrier or modulation, but you can slightly hear it key up on another radio on my bench. The PA works just fine and the recieve is fine. Any Ideas on what the problem might be??
PS. this is a Tiawan model
Thanks
Buck |
Buck
| | Posted on Tuesday, February 04, 2003 - 9:22 am: |
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What years were the Tiawan models made??? |
307
| | Posted on Tuesday, February 04, 2003 - 9:57 am: |
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If it has a "slight" carrier , IE , you can hear it on another CB close by...It is the Final ,I take it that there is no TX on SSB , Correct?
307 |
Gopher
| | Posted on Tuesday, February 04, 2003 - 3:48 pm: |
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Yes,Buck, 307 is right. but check for a cold solder on the back side of the PC board on the final first befor you just put a new one in, the old one might still be good. |
Buck
| | Posted on Tuesday, February 04, 2003 - 3:58 pm: |
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Thats correct 307..absolutly dead. There isnt a carrier at all. with a radio right next to it you can just barely tell you keyed up by a bit of scratchyness on the other radio but no carrier. 2600 gave me a suggestion about an electrolytic cap which I havent had a chance to check out yet. I posted this in the open forum before he posted in the mobile radio section. I will try it out and let you know what happens
Thanks
Buck |
Buck
| | Posted on Tuesday, February 04, 2003 - 9:36 pm: |
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2600 had the right answer....Bad cap....C95 Problem is taken care of |
2600
| | Posted on Tuesday, February 04, 2003 - 11:38 pm: |
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Way Cool!!
Some days I just love being right. I'll give you credit for NOT just ripping the final and driver out without testing them. Some folks try that first and THEN ask for advice. Just muddies the water, especially if something else gets hurt in the attempt.
If the receiver (only) audio mysteriously goes dead, and the S-meter still shows channel activity, you will find that C186, a 220uF 10 VOLT cap (near the audio chip) has done the same thing.
Sounds like a good subject for a web page; "The Ten-Volt Blues", or something like that. A picture with arrows to C95, C186, C153 (mysterious drop in transmit power and final bias test registers zero) and C18 (no mike audio AM or SSB or PA) could save folks with twenty-year old radios some real trouble.
Some things just aren't meant to last more than twenty years. Congragulations.
73 |
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