I'm new to this but I have a dx-44v that receives fine but will not transmit. The meter doesn't move or anything. Are the finals shot or could it be something else... Please help....
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DX-44V no transmit
- Thread starter chevelle69350
- Start date
could be the driver, the final or both.
does the RX/TX light change when you key the mic?
are there any details you can give about how or when this first happened?
the more details, the better help can be given.
LC
does the RX/TX light change when you key the mic?
are there any details you can give about how or when this first happened?
the more details, the better help can be given.
LC
dx-44v
rx/tx light changes when I key up and I hear the roger beep but no signal out. and i don't know when it first stated doing this,a trucker friend of mine ask me to check it out for him. It had a 200w amp bolted to the bottom case of the unit. It worked fine when I tested it on a different unit I had. But with or without the amp the dx-44v will not transmit. also I noticed when I key up it doesn't draw any power on my power supply. meaning the needle doesn't drop on my power suppy as if it were drawing more power.
rx/tx light changes when I key up and I hear the roger beep but no signal out. and i don't know when it first stated doing this,a trucker friend of mine ask me to check it out for him. It had a 200w amp bolted to the bottom case of the unit. It worked fine when I tested it on a different unit I had. But with or without the amp the dx-44v will not transmit. also I noticed when I key up it doesn't draw any power on my power supply. meaning the needle doesn't drop on my power suppy as if it were drawing more power.
ok, my guess is that the final transistor is bad.
usually the driver survives whatever condition made the final go, but sometimes it will go bad right along with the final.
first thing to do is test them both.
for this you will need a digital multimeter with a "diode test" function.
most digital meters over 30 dollars will have this feature, as will some of the cheaper ones.
this test can be done with the old analog style meters, but you will have to google it to get the procedure as i am not familiar with it.
first step is to unsolder and lift all three legs of each transistor (driver TR44 and final TR43). make sure that none of the legs are touching the PC board traces.
once that is done position the radio with the solder side (green side) of the PC board up, and the front of the radio facing you.
both the driver and the final have the same lead configuration (ECB) from left to right.
E is the emitter
C is the collector
B is the base
lets start with the driver (2SC2166)
set the multimeter for the diode test function, and put the red lead on the Base of the transistor (right leg).
put the black lead on the emitter (left leg)
you should see a reading of between .4 and .9 volts on your meter.
leave the red lead where it is and move the black lead to the collector (middle leg). you should get almost the same reading as the previous test (somewhere between .4 and .9 volts)
if you get an "open" or "shorted" reading on your meter during either of these tests, the transistor is probably bad and should be replaced.
now reverse the leads, putting the black lead on the base and the red lead on the emitter. the meter should read "open" or no connection.
leave the black lead on the base and move the red lead to the collector.
the meter should read "open" or no connection.
if it reads shorted, it is probably bad.
repeat these same tests on the final transistor (2SC1969).
if it fails any portion of the tests, it should be replaced.
i am guessing that one or both of these transistors is bad, and they can both be hard to find and expensive when you do find them.
one option you have is to convert the final to a mosfet, or both the driver and final to mosfets.
if you choose to go this route, here is a link to the procedure:
http://www.cbtricks.com/miscellaneous/fet_papers/ekl/index.htm
just find the one for your radio.
as for why this happened in the first place, your friend might have a high SWR between his radio and amp.
when you run an amp you need to check the SWR going into the amp and the SWR going out of the amp.
hope this helps,
LC
usually the driver survives whatever condition made the final go, but sometimes it will go bad right along with the final.
first thing to do is test them both.
for this you will need a digital multimeter with a "diode test" function.
most digital meters over 30 dollars will have this feature, as will some of the cheaper ones.
this test can be done with the old analog style meters, but you will have to google it to get the procedure as i am not familiar with it.
first step is to unsolder and lift all three legs of each transistor (driver TR44 and final TR43). make sure that none of the legs are touching the PC board traces.
once that is done position the radio with the solder side (green side) of the PC board up, and the front of the radio facing you.
both the driver and the final have the same lead configuration (ECB) from left to right.
E is the emitter
C is the collector
B is the base
lets start with the driver (2SC2166)
set the multimeter for the diode test function, and put the red lead on the Base of the transistor (right leg).
put the black lead on the emitter (left leg)
you should see a reading of between .4 and .9 volts on your meter.
leave the red lead where it is and move the black lead to the collector (middle leg). you should get almost the same reading as the previous test (somewhere between .4 and .9 volts)
if you get an "open" or "shorted" reading on your meter during either of these tests, the transistor is probably bad and should be replaced.
now reverse the leads, putting the black lead on the base and the red lead on the emitter. the meter should read "open" or no connection.
leave the black lead on the base and move the red lead to the collector.
the meter should read "open" or no connection.
if it reads shorted, it is probably bad.
repeat these same tests on the final transistor (2SC1969).
if it fails any portion of the tests, it should be replaced.
i am guessing that one or both of these transistors is bad, and they can both be hard to find and expensive when you do find them.
one option you have is to convert the final to a mosfet, or both the driver and final to mosfets.
if you choose to go this route, here is a link to the procedure:
http://www.cbtricks.com/miscellaneous/fet_papers/ekl/index.htm
just find the one for your radio.
as for why this happened in the first place, your friend might have a high SWR between his radio and amp.
when you run an amp you need to check the SWR going into the amp and the SWR going out of the amp.
hope this helps,
LC
Thanks Loosecannon. It wouldn't hurt my feelings to just convert it to a mosfet. Seems to be a easier fix. I just have to find someone to do it. I'm not that good when it comes to soldiering. The guy gave me the radio, so it's worth it to take it to be fixed.
well i understand your timidity if you dont have much experience with soldering.
im sure you can find a shop by searching around this forum and finding out who everyone recommends.
good luck,
i hope it was just the final,
LC
im sure you can find a shop by searching around this forum and finding out who everyone recommends.
good luck,
i hope it was just the final,
LC
I had a 66 with a problem similar to the one described here and i was able to get it working by replacing a bad diode. This diode was on the board just below the mic socket. You might want to check out the possibility if it turns out not to be the finals. Good luck with your radio. I paid $50 for the cherry 66 with problem, and getting it working put a big smile on my face. I`m no expert........just got lucky.