Good Morning everyone from Stuck in the mud in Muncie In. 673 Hope everyone had a great Thanksgiving. I have a Sears Roadtaker 40 can anyone tell me what diode is the protective diode in this radio? Thank you very much 73s
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
Sears roadtalker 40ssb Model # 934.38260700
- Thread starter Stuck in the mud
- Start date
D504. Follow the power in from the positive terminal through the fuse, then to the choke L501. On the other side of the choke is D504. Sam's CB-254 has that as a "WO6A", but one of the equivalents is a 1N4001. So pretty much any rectifier diode with a PIV rating of 600V and current rating of 1 Amp (or higher) will do.
If you're having trouble physically locating the diode, Looking from the front of the radio speaker side up, it's in the back right corner. It will be right in front of the small transformer looking thing, which is L501. You will probably have to move the heatsink and small AM power control pc board in your pic to see it.
If all you're doing is replacing the diode, you can probably just unscrew the heatsink from the side of the chassis and move it out of the way. Be prepared to redo the heatsink grease, though. The small pc board is attached to the heatsink, so it will go wherever the heatsink does to the limits of the attached wires.
If you're having trouble physically locating the diode, Looking from the front of the radio speaker side up, it's in the back right corner. It will be right in front of the small transformer looking thing, which is L501. You will probably have to move the heatsink and small AM power control pc board in your pic to see it.
If all you're doing is replacing the diode, you can probably just unscrew the heatsink from the side of the chassis and move it out of the way. Be prepared to redo the heatsink grease, though. The small pc board is attached to the heatsink, so it will go wherever the heatsink does to the limits of the attached wires.
Thanks TM86 for the reply I think the diode is good The orange wire on the volume control I have 13.90 v. on C505 I have 13.89 v on one leg and 13.88 v. on other leg.
On C319 I have 10.65 v But on the orange wire on PA I have zero v and the same on the red wire on CB zero v I am new at this just trying to learn if you have the time Thanks a bunch Dale
The radio does not light up
On C319 I have 10.65 v But on the orange wire on PA I have zero v and the same on the red wire on CB zero v I am new at this just trying to learn if you have the time Thanks a bunch Dale
The radio does not light up
Last edited:
What are you trying to troubleshoot?
List what works, what don't work.
Does it even come on?
73
Jeff
List what works, what don't work.
Does it even come on?
73
Jeff
You may need a bigger brain than mine to help on this one.
First thing I would check, after finding 13.88 V on the ground leg of C505 (disconnect power first) is does the board ground actually have a connection to the negative power lead. An ohmmeter set to continuity test should be able to tell you that. I know this sounds rather basic, but sometimes the problem is easier than we want to believe. Not often enough, though.
One side of that cap should be zero volts, because it's supposed to be attached to the board ground. The radio not lighting up could be no voltage drop across the light bulbs (due to ground being not right) , one light bulb burned out (they're wired in series), or both light bulbs burned out, which would be a little weird.
First thing I would check, after finding 13.88 V on the ground leg of C505 (disconnect power first) is does the board ground actually have a connection to the negative power lead. An ohmmeter set to continuity test should be able to tell you that. I know this sounds rather basic, but sometimes the problem is easier than we want to believe. Not often enough, though.
Sorry it has taken me so long to get back on here. Had a battle with covid and have been busy with the holidays. This radio lights up now has sound. If you key up with a dummy load the SWR light comes on but I have no carrier. If I connect to my antenna I have no receive. Any help would be appreciated. Thanks Dale
Two questions:
Does the S-meter needle move at all when unplugging the antenna? Should move up when the antenna is plugged in, especially when the skip is running.
Turn the squelch knob from end to end with the volume turned full up. Do you hear a "pop" or "thump" sound while twirling the squelch knob?
Each of those tests can serve to narrow down where to look.
The usual question I ask about a radio that's dead on transmit and receive both is "how many people have tried to fix it so far?".
If you weren't around to observe when the radio broke down, any number of fingers may have been inside it.
73
Thanks for the reply back Nomadradio. The radio does not move when you plug or unplug the radio in with skip running with radio on. I do know the meter works.
Turning the squelch does not change anything no sound difference.
No one else has worked on this radio for years.
Back in the late 70 I had the upper and lower channels put in the radio. I talked on it until the yearly 80 then it lost transmit and receive I stopped talking back then. Got back into talking about 3 years ago got this radio back out and am trying to bring it back to life. When you first turn the radio on you hear static and pop and cracking like something is shorting out but see nothing in the radio. It only last for 2 or 3 minutes. Then the static and pop and cracking leaves. Thanks
Would anyone out there have time to write down the components that runs through the receive circuit, the transmit circuit and the audio circuit on a CB radio I am trying to learn how to read the schematic and learn all the different components through the radio thanks I would appreciate it if anyone had the time to do that 73s
Would anyone out there have time to write down the components that runs through the receive circuit, the transmit circuit and the audio circuit on a CB radio I am trying to learn how to read the schematic and learn all the different components through the radio thanks I would appreciate it if anyone had the time to do that 73s
I believe that radio is in CB PhotoFacts volume #254. Go here and ask Dan to make a .pdf of the section that covers your radio. It will have everything you are looking for.
www.worldwidedx.com
Good Luck.
Sams PhotoFacts Collection
My pleasure, Steve.... Dan Do you have a PDF file of 254
Good Luck.
- No one is chatting at the moment.
-
-
dxBot:63Sprint has left the room.
-
dxBot:kennyjames 0151 has left the room.
-
-