Ihave a TRC-458 navaho realistic that has no A.M. tx and relay chatter on ssb.I beleive the problem may be a small 2.2 uf 25v electrolytic tantalum cap in the final output circuit,problem is i can't find the bugger. the board is not readable in places and i have spent over an hour with the trusty old magnifing looking, no luck. Tho cap number on the board is C-179.A diagram or detailed discription of its exact position would be greatly appreciated. TNX Warlock35po
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Realistic Navaho TRC-458 A.M. tx problem and sideband relay chatter.
- Thread starter Warlock35po
- Start date
look near the driver and final.
you will see two jumper wires (probably white) with bullet connectors on the ends. these two jumpers provide bias to the driver and final and are made to be removable so you can put a current meter in series with them and set the driver and final bias.
they are short jumpers, only a couple of inches long.
you will see that they both originate from the same area, and one goes to the driver and one goes to the final.
look at the ends of the jumpers that are opposite the driver and final ends.
right between them you will see a very small blue lump.
that is C179.
very common to go south.
most people replace it with an electroytic capacitor, 2.2uF and 16 volts or higher. just make sure its physically small enough to fit.
make sure you get the polarity right.
if its not marked with a "+" sign on the board, then the positive lead goes to the "final" side, and the negative lead goes to the "driver" side.
good luck!
LC
you will see two jumper wires (probably white) with bullet connectors on the ends. these two jumpers provide bias to the driver and final and are made to be removable so you can put a current meter in series with them and set the driver and final bias.
they are short jumpers, only a couple of inches long.
you will see that they both originate from the same area, and one goes to the driver and one goes to the final.
look at the ends of the jumpers that are opposite the driver and final ends.
right between them you will see a very small blue lump.
that is C179.
very common to go south.
most people replace it with an electroytic capacitor, 2.2uF and 16 volts or higher. just make sure its physically small enough to fit.
make sure you get the polarity right.
if its not marked with a "+" sign on the board, then the positive lead goes to the "final" side, and the negative lead goes to the "driver" side.
good luck!
LC
I have worked on a lot of these radios and would not use anything less than a 35 volt cap.
Jim
Navaho-458 Problem
Thanks for the info,loosecannon and slprfdk, greatly appreciated. Best regards. Warlock35po.
Thanks for the info,loosecannon and slprfdk, greatly appreciated. Best regards. Warlock35po.
Jim,
thanks for the tip.
i will do that from now on.
oh BTW, the fix for the 138XLR WAS R204.
it works now, but low power out and no mod.
thanks for all the help on that.
sorry for the hijack there warlock.
you can trust jim's advice. he's been doing this a long time.
LC
thanks for the tip.
i will do that from now on.
oh BTW, the fix for the 138XLR WAS R204.
it works now, but low power out and no mod.
thanks for all the help on that.
sorry for the hijack there warlock.
you can trust jim's advice. he's been doing this a long time.
LC
Re:"Realistic Navaho TRC-458 A.M. tx problem and sideband relay chatter."
I have the same radio with the same problem , I have found the small 2.2 uf 25v electrolytic tantalum cap that seems to be causing the problem but I am having a hard time finding a electroytic capacitor, 2.2uF and 16 volts or higher I have however can find a 2.2uF/50V Radial Electrolytic Capacitor will these work as a replacement .
Or does anyone have a site that I can by the proper capacitor ....
thanks in advance if you can help me out with this I really like to get this radio back up and running .
I have the same radio with the same problem , I have found the small 2.2 uf 25v electrolytic tantalum cap that seems to be causing the problem but I am having a hard time finding a electroytic capacitor, 2.2uF and 16 volts or higher I have however can find a 2.2uF/50V Radial Electrolytic Capacitor will these work as a replacement .
Or does anyone have a site that I can by the proper capacitor ....
thanks in advance if you can help me out with this I really like to get this radio back up and running .
the 50v cap is the one to use.
you can always use a higher voltage rated cap as a replacement.
i only said 16 volts or higher because the radio operates at 14volts.
make sure you get the polarity right. + to + and - to -
LC
you can always use a higher voltage rated cap as a replacement.
i only said 16 volts or higher because the radio operates at 14volts.
make sure you get the polarity right. + to + and - to -
LC
navaho 458 tx problems
Ok well I replaced the 2.2 uf 25v electrolytic tantalum cap with the 2.2uf 50v capacitor however it is still not working . I don't see any chatter on the ssb now however the needle when keyed is still not showing any tx power , when used next to a portable cb radio I have it works ok etc... but just no tx power to go out long distance .
Any other idea's I know its not the mike as I say it tx fine when the portable is sitting right next to the radio it just don't have anything to push out power as the needle stays dead .
Thanks in advance for any help you may give me
Ok well I replaced the 2.2 uf 25v electrolytic tantalum cap with the 2.2uf 50v capacitor however it is still not working . I don't see any chatter on the ssb now however the needle when keyed is still not showing any tx power , when used next to a portable cb radio I have it works ok etc... but just no tx power to go out long distance .
Any other idea's I know its not the mike as I say it tx fine when the portable is sitting right next to the radio it just don't have anything to push out power as the needle stays dead .
Thanks in advance for any help you may give me
Kind of sounds like something after the driver and before the final, assuming the final is good Regards warlock35po