| Author |
Message |
    
Tombstone
| | Posted on Sunday, February 02, 2003 - 3:29 am: | 
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Greetings from my Radio Slum! My 148 GTL-DX quite suddenly lost transmit on AM. SSB seems to be fine. My watt meter reads 30 watts on AM transmit with no modulation and final transistor (2312)is scalding hot. Could this be a bad voltage regulator? If so, is it a transistor or an IC and where is it located? Also, can a 1969 final be used in place of a 2312? Thanks so much; I can't work skip until this is resolved!!
Tombstone/222 |
307
| | Posted on Sunday, February 02, 2003 - 6:31 pm: |
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Yes..Yes..and Yes..It is most likely the AM Power Regulator on the side of the radio that is shorted..
307 |
2600
| | Posted on Monday, February 03, 2003 - 1:21 am: |
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The only "148GTL-DX" I know about has the number "PB-010" on the circuit board. If yours has that circuit board, odds are that you need to replace TR51, the 2SA1012 bolted to chassis, and TR50 the 2SB525 that drives it. If one is bad, the other one should be. Beats frying a new part because the one you DIDN'T replace was bad, too. TR52, next to TR50 is a generic little plastic 2SC945. If the 150 ohm half-watt resistor R295 next to it looks overheated, TR50 and the resistor should go, too. Just make sure you use a sufficient layer of the white silicone-grease "heat sink compound" installing TR51. Won't last long without it.
73 |
Tombstone
| | Posted on Tuesday, February 04, 2003 - 6:31 pm: |
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Thanks, Guys,
I'll be sure to check it out thoroughly!
Rich Brock |
Tombstone
| | Posted on Wednesday, February 05, 2003 - 7:05 pm: |
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Hi, Guys,
I replaced the voltage regulator and the radio is barking again! The driver and the 150 ohm resistor are fine. Thanks for the great info.
Rich |
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