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142 bias
- Thread starter stingray
- Start date
might be that little diode bolted to the heatsink near the driver.
i have had this problem before on a 139xlr and that diode was the culprit.
Cobra 153010N001 Varistor For Cobra 142 146 & 148 Radios
pretty sure that is the part you want.
good luck,
LC
i have had this problem before on a 139xlr and that diode was the culprit.
Cobra 153010N001 Varistor For Cobra 142 146 & 148 Radios
pretty sure that is the part you want.
good luck,
LC
the radio is working fine (or technically is it?) is this something to worry about?might be that little diode bolted to the heatsink near the driver.
i have had this problem before on a 139xlr and that diode was the culprit.
Cobra 153010N001 Varistor For Cobra 142 146 & 148 Radios
pretty sure that is the part you want.
good luck,
LC
well, i guess thats all in the eye of the beholder.
the driver should be set at something around 25mA, and yours is at 100mA+.
that says that something is not doing its job correctly.
i am only guessing, but it might weaken the driver prematurely to run it like that.
do some tests.
key the radio down for 30 seconds and feel the driver and the heatsink around it.
does it seem too hot?
try it for 1 minute.
you should be able to key the radio down for 1 minute without blistering your finger on the heatsink so to speak.
im not a tech, just relating my experience with this phenomenon.
maybe someone with more tech knowledge than me will chime in here and tell you the why's.
i think i remember reading somewhere that the bias setting on the driver and final determines the amplifier class of the transmitter.
so maybe if yours is not biased correctly, you might not be running class AB1.
sorry i cant be more help explaining why this may be a problem, but if i tried, i would probably dig myself in a hole. LOL
good luck,
LC
the driver should be set at something around 25mA, and yours is at 100mA+.
that says that something is not doing its job correctly.
i am only guessing, but it might weaken the driver prematurely to run it like that.
do some tests.
key the radio down for 30 seconds and feel the driver and the heatsink around it.
does it seem too hot?
try it for 1 minute.
you should be able to key the radio down for 1 minute without blistering your finger on the heatsink so to speak.
im not a tech, just relating my experience with this phenomenon.
maybe someone with more tech knowledge than me will chime in here and tell you the why's.
i think i remember reading somewhere that the bias setting on the driver and final determines the amplifier class of the transmitter.
so maybe if yours is not biased correctly, you might not be running class AB1.
sorry i cant be more help explaining why this may be a problem, but if i tried, i would probably dig myself in a hole. LOL
good luck,
LC
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@ heartbreaker3473:Hello gentlemen and Ladies. I have the dreaded RCI-2990 receive issue where my radio gets distorted when people get close to my location. I found the C90 Capacitor, but I can not for the life of me find the C89 capacitor. Can or does anyone have a picture of the exact location of C89 ? Thank you in advance, Wes
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@ AudioShockwav:Wes, it's better if you start a thread on the main forum, more people are going to see your question.
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@ heartbreaker3473:I put it in the general disscution help area and started a new thread. Thank you for letting me know.