| Author |
Message |
    
Flybynight
Member
Username: Flybynight
Post Number: 64
Registered: 10-2002
| | Posted on Thursday, March 25, 2004 - 7:59 pm: | 
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This 25LTD classic was made in 2000.Has the combined volume/squelch switch with mic connector on the front.I had to replace the modulation transformer and audio IC.Radio recieve's great.But,when you key the mic,the recieve is cut out,meter fall's back to zero,but the red tx led wont light up.The led work's for recieve though.I noticed when i key it up and have a radio on close to it,it send's a signal but really weak.I replaced TR17,still same thing.I also replaced the final and driver transistor.I'm out of idea's.Would very much appreciate any help in tracing the problem.Thank's in advance!
Danny |
Lasthighlander
New member
Username: Lasthighlander
Post Number: 8
Registered: 8-2004
| | Posted on Tuesday, August 24, 2004 - 10:07 pm: |
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Have you peaked and tuned the radio? Maybe you did the mod that changes out a diode and couple of resistors? I did this to a 25 a few years back, got the mods off a website, all in all the radio wound up as parts and I haven`t done that same mod to any since.I would go and check all the mods you or someone else has done first, then maybe check the mic itself and possibly the transmit wire in the mic and at the mic post on the radio. I have seen a couple that have the little board at the mic post and one or 2 of the chokes they have go bad. Hope this helps |
Tech548
Moderator
Username: Tech548
Post Number: 262
Registered: 5-2004
| | Posted on Wednesday, August 25, 2004 - 4:43 am: |
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Flybynight
Start at the Mic and work your way in on the transmit keying circuit. I don't recall off hand at the moment what or where TR-17 that you are refering to is, but I'm thinking that the transmit switching transistor may have taken a dive. TR-6 seems to ring a bell with me but I'm not really sure anymore because it's been a while since I've played with these radios.
Hopefully you have a schematic to follow your tracing with. The switching transistor I'm refering to is usually a standard 2SC945 and will be around or near the front right-hand side usually in the vacinity of the Mic jack. These 945's are used in many circuits throughout the radio.
I could be way off base here but since I don't know this radio personally, I would start at the Mic itself and work my way in.
Also, I'm curious to know why you had to change the audio transformer and chip both?
Jeff
Tech548 |
Brownsmillsch18
New member
Username: Brownsmillsch18
Post Number: 5
Registered: 2-2004
| | Posted on Tuesday, February 08, 2005 - 12:08 am: |
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check the PA switch, many times I jumped the gun on this problem, lol.
-Little Ranger- |
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