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Road King RKCB Classic UT414

Hawkeye351

Well-Known Member
Jun 27, 2021
521
402
73
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Got a Road King RKCB Classic (UT414) on the desk. It was given to me in a trade, and now a new guy on the air wants a nice 40 channel radio but can't afford much, so I decided to fix this one and set it all up for him. I'm giving it to him because it was given to me and he can't really afford much.

After hooking it up I noticed the receive was about 3 s-units down and quiet. So I tried to find the service info to align it, but no luck in finding the needed alignment info.

I also noticed it had no transmit, so I checked the collector of the driver and final. Both driver and final seemed fine, just the base voltage was below 2v and wasn't switching on the MOSFET, it wouldn't adjust no higher that 2.35v. Upon just looking around around the board for burnt traces or some tom foolery, I found a disc cap tied to the output coil and leading off to the chassis ground. This didn't look factory, the wire looked overheated at the solder ends and the solder didn't look the same as the rest of the board. I removed one end, and BAM, got a carrier and modulation.

Deadkey - 9w,
PEP swing - 50w
Peak swing - 31w
Average swing - 18w

The receive came up and sounded amazing also when I removed one end of that disc cap.

All functions work as brand new, radio looks brand new, board looks brand new, excellent output, excellent receive. Only issue is, I need the service manual for alignment, or someone that's done one of these before to share how they aligned theirs. I would also like to know how to drop the deadkey down from the current 9w level to around 4w while maintaining the max 50w swing. I know about adjusting L204 (I think) to drop the key, but the swing drops with it, pretty much staying in the 4:1 range by itself. Anyone know how to drop this key without detuning down the swing?

Thank you all in advance.
 
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“JP36” mod or the TIP120 variable key mod if it’s a transformer modulated radio. NPC mod if it’s a darlington modulated radio. I don’t have that radio so I can’t tell which one it is. I’m sure our resident expert Spit will be around to lend his opinion shortly
 
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Requires a trace cut on the solder side of the pc board. No handy jumper wire like in a Cobra 29/PC76 radio. I'm sure I have seen this pc board, but can't remember the brand/model on the radio.

I have a fuzzy memory of shooting pics of adding carrier control to this pc board.

Only way to find it would be by the radio's brand and model. That's how those files are identified.

73
 
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Was talking on this radio last night, and getting great audio reports. The guy that's getting it wanted it like it is, so I gave it to him. And yes it does sound amazing on the air, I talked to him last night after he got it home and hooked up. He said his meter is showing halfway between 25w to 30w swing, he's using a dosey. I asked him to keep a check on heat building up around the final area every once in a while, so far he says it stays cool to warm no matter how long he stays on the key.

Gotta say, I'm impressed with that Road King.
 

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