| Author |
Message |
    
Rattletrapp
New member
Username: Rattletrapp
Post Number: 3
Registered: 2-2004
| | Posted on Monday, July 05, 2004 - 10:30 am: | 
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I have a (made in the malaysia) 148 gtl that will not key up on am. the transmit indicater light comes on but there is no power out.am receive is good,ssb transmit & receive is good
just no am transmit.everything else works great. pleeeeeeeeese help. |
Tech8541
Moderator
Username: Tech8541
Post Number: 230
Registered: 12-2003
| | Posted on Thursday, July 08, 2004 - 1:22 am: |
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there is an am regulator that has most likely gone bad...can't remember the location but i think it is a 2sd1135..may be way off...if so maybe someone else can correct me. in any event i would bet that the reg is bad
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Rattletrapp
New member
Username: Rattletrapp
Post Number: 4
Registered: 2-2004
| | Posted on Thursday, July 08, 2004 - 12:42 pm: |
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Thank you, Tech8541.
Found that transistor # d1135 will swap it out
and see what happens.
Thanks again.
Rattletrapp. |
Tech548
Moderator
Username: Tech548
Post Number: 125
Registered: 5-2004
| | Posted on Friday, July 09, 2004 - 3:06 pm: |
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Rattletrapp
Here's something else you can try.
Look for IC-3 (AN612 balance modulator chip) near the front-center of the circuit board. It's about 3/4 inch long, 1/4" tall, black plastic and has seven pins in line soldered to the board, mounted parallel to the sides of the radio.
At the rear end of this chip (on the left side of IC-3) is a tiny electrolytic capacitor (C-95) marked 47uF with a 10 volt rating.
Unsolder one leg of this capacitor or just remove it completely. If your wattmeter now comes back to life when you key the radio, replace the capacitor.
Use a higher voltage rating such as a 16 or 25 volt. Capacitors with a 25 volt rating will live a lot longer than do the ones with lower ratings. Any value up to about 220uF will work OK as long as it fits in what little space is provided.
Another thing to look for in this area is a 100 ohm resistor (R-108) that feeds this spot next to C-95. If the resistor looks like it is discolored, then it has been overheated. Replace this resistor also.
Jeff,
Tech548. |
Rattletrapp
New member
Username: Rattletrapp
Post Number: 5
Registered: 2-2004
| | Posted on Saturday, July 10, 2004 - 5:38 pm: |
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Thanks. Tech8541 and Tech548.
Tried both of your suggestions. but neither one was the problem this time. Turned out the board had a cold solder joint on one of the resistors. what a pain it was hunting it down
but persistance paid off. its working like a charm now. thank you both very much.
73s Rattletrapp. |
