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Royce Model 619 CB Radio Question

Riverman

Sr. Member
Nov 12, 2013
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I love this radio. It reminds me of the 1970s when I was really into CB.

Can someone identify the modulation and carrier pots fo me?

Here's a schematic. There's a block diagram on page 10 of the manual.

Royce 619


Thanks!
 
Last edited:

Never mind!

Found the info I was looking for on page 14 of the manual.

Royce 619

Have decided, however, not to fool with these modifications myself. It might be that when I receive my new mic (CR577), modulation will be just fine.
And although I was wanting to drop my dead key to around 2 watts, it appears there are three power adjustments involved and that's more than I want to fool with.

Best leave that to the experts.
 
Glad you didn't mess with those tuning coils. If anything, the should be peaked. They form a network of impedance matching from the synthesized audio/freq to the driver/final transistors. There was a thread somewhere on the forum that showed how to lower the dead key by adding 3-4 diodes in series, but cannot recall the name of it.

Noticed in the schematic that your radio uses a 2sc2166 for the final. This particular transistor is usually used as a driver transistor and not a final transistor. So at best it can only do ~12 watts peak power; and even that is pushing it.

2SC2166 pdf, 2SC2166 description, 2SC2166 datasheets, 2SC2166 view ::: ALLDATASHEET :::
 
Glad you didn't mess with those tuning coils. If anything, the should be peaked. They form a network of impedance matching from the synthesized audio/freq to the driver/final transistors. There was a thread somewhere on the forum that showed how to lower the dead key by adding 3-4 diodes in series, but cannot recall the name of it.

Noticed in the schematic that your radio uses a 2sc2166 for the final. This particular transistor is usually used as a driver transistor and not a final transistor. So at best it can only do ~12 watts peak power; and even that is pushing it.

2SC2166 pdf, 2SC2166 description, 2SC2166 datasheets, 2SC2166 view ::: ALLDATASHEET :::

Yeah, didn't want to take a chance on really messing it up. Far as I know, it works fine as is. Just have that disease all CB'rs get early on--more, more. I want more. :)

As I said in another thread: Time to quit dreaming and break out the wallet.
 
Last edited:
Have decided to sell my Royce 619 and get a radio with SSB and variable power. Will be upgrading my antenna as well.
 
If I remember correctly that was not a typical Royce inside with all the model boards mounted about like how we mount PCI boards in a computer. That one was an affordable unit. I think those where missing a pot to adjust modulation. I think those where the sort of unit's where the modulation adjustment was to cut the resistor in the AMC circuit. In the old 1970 units they used transistors in the final area that where barely able to do the legal limit and often they left keying 3.4 watts and 60% modulation which gave birth to the power mic. Often they did not give you a pot to adjust bias using fixed value parts and keeping the bias low low low which guaranteed no unit left the factory over the legal limit. Even with coaxing with out installing a better final you could at best turn them down to 1-2 watts and get them to swing to 4-8 watts. This was fine because plenty of low power tube and transistor amp's where available that did not need much drive. In fact a lot of units had such anemic modulation circuits that even cutting the AMC often would not produce clipping if no power mic was used. If the power mic was set right again you might be able to again not hit 100% very often. That all changed though. The cheaper units though even into the 80's often deleted control pots and used PLL's that had pll and VCO function built in eliminating most mod's to "cut this part"!!
 
I opened an old box with a new Royce model 619 in it. It has never been opened , works great
 

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