TRC-431 DeadKey Adjustment

[radiopirate]

I just thought I'd throw this out to the group... and maybe i'll get lucky...

I've got an old "backup" TRC-431 that I would like to add a small stinger board to. Current DK is right around 4w.

Does anyone happen to know a simple way to adjust the deadkey down to about 2w? Do I even need to worry about it since the DK is already so low?

Thanks in advance for any replies!

[Sheriff Bart]

L910 according to cb tricks


3's

[radiopirate]

Ah...Roger That, Sherrif. I see it now. Looking at the schematic (I'm not home right now) it looks like L910 is a vcap and I can easily adjust it. I hope so!

[radiopirate]

So, then... if i do decide to add the stinger, is this adjustment something that I absolutley must be concerned with, or should the board be ok with the stock 3-4 watts coming in?

[sparky17]

I cringe giving 3-4 watts to a 2x1446... Don't you dare do that to a stinger board unless you want to replace the "RM3s"

IRF520's will work if you blow them out tho, so.. I guess it's < $10 and your time, which isn't THAT much risk..

The KL203 is the same thing, but in a box. I had one of those blow within a month of using radios that were 3-4w deadkey... Coincidence? Maybe.. If you're comfortable soldering then I'd say go for it... It'll do it for a while

[radiopirate]

Well... I'm not too keen on having to do any repairs unless it is necessary. I'd rather devote the little free time I get to doing fun stuff like upgrades and tweaks; but if I have to, I can probably handle the transistor repalcement. You say IRF520's will work as substitutes...are they any better than the originals, or just maybe easier to get?

Thanks!

[sparky17]

They're the same.. RM3s might be cherry picked however.

Actually, I was thinking it terms of the KL203 which is a heatsink.. If this thing is going to be inside your radio it's going to get incredibly hot incredibly quick. You could probably only get away with 5 seconds of keydown per minute..

[radiopirate]

Yeah, I agree. I've actually added some small holes to the radio case right in area where the board will mount. I plan to add a small 12vdc fan at the new holes. I will also shield around the entire board with some old foil-on-one-side A/C duct tape (leaving plenty of room for air flow!). I've found that that old foil tape is great stuff for shielding - as long as you are careful about where you put it and what it may touch when it's there!

Thanks!

[dime196604]

I am very interested i have that same radio what are these stinger boards? i know they are like small amps but do you find them? are they universal do they hook up to any radio? and how hard i the install?

[dime196604]

L910 according to cb tricks


3's

sheriff bart if you adjust the L910 would it throw you radio off frequency at all? what i mean is could you adjust it with a watt meter and have every thing be ok?

[radiopirate]

dime: You can find the boards online very easily. I don't want chance violating Forum rules by posting here the name of the particular supplier that I regularly use; but, just do a quick Google. If you still have trouble, shoot me an IM or email and I'll help you out.

[dime196604]

dime: You can find the boards online very easily. I don't want chance violating Forum rules by posting here the name of the particular supplier that I regularly use; but, just do a quick Google. If you still have trouble, shoot me an IM or email and I'll help you out.

Oh i have found lots of them on the net since i posted that. i like what i see so far they push good watts for their size and you can find lots of them for 40 bucks and under

[Sheriff Bart]

L910 according to cb tricks


3's

sheriff bart if you adjust the L910 would it throw you radio off frequency at all? what i mean is could you adjust it with a watt meter and have every thing be ok?

yes, according to the block diagram L910 will only adjust the deadkey.
here's the link [Please login or register to view this link]
and at the bottom of the page you'll see "adjustments"


3's

[Night Crawler]

if you adjust the L910 would it throw you radio off frequency at all?

L910 can be adjusted to lower the output but by doing so it will detune the final amplifier from resonance not a really good thing to do.

[dime196604]

if you adjust the L910 would it throw you radio off frequency at all?

L910 can be adjusted to lower the output but by doing so it will detune the final amplifier from resonance not a really good thing to do.

So what would be a good safe way to get the DK down on these radios? I justed picked up a very old 1x4 that works and i don't wanna fry it in a week of using it.

[Night Crawler]

So what would be a good safe way to get the DK down on these radios?

Remove R921 a 8.2 ohm resistor (gray red gold) and replace it with a higher value.
Optional (put a cap across it if you want the swing)