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2sc2290 in a connex or galaxy

Well, the idea was to preserve the method used - nowadays they use those 7530 MOSFETs that pretty much put out the same power levels.

The rest of this you can read at your leisure --- was done for a previous site but I sent this as a series of Emails PM'd from me to another that wanted to install such a kit - these things don't exist anymore but were from CBC Intl amongst others and several variants were done/sold back then for those that wanted a boost but also a way to keep their radios from blowing up in heavy use and mobile environments. It's condensed and reworded so if you feel inclined to use it - give credit where credit is due...

---
But the 2290 I had one myself that used a daughter card like the one shown above, only it was packed with discretes - which included an RF sense for auto TX so I wanted to help some one keep theirs going on an older SS3900. It was a kit

So this was a "training manual" for someone they wanted to install this in their AM/SSB radio...it had limitations - setup was for Class C and mostly driven by Final with it's power backed way down. 2 watts or less.

You got the board, a relay - a series of "stand - off" tabs - the daughtercard and several (12 discretes) parts and wire...you soldered the kit together placing the 2290 in the middle. Its lot like what is shown above - only the above is the SMD version with a lot of extra space...the standoff was used for with the filter network for TX relay or for point to point wiring of the TX sense using 8V+ or Ground (TX pin 3 ground and the needed support filtering and steering diode to prevent voltage from damaging the board).

The real purpose of this "method" was to make a modulator - you had two choices with the kit, replace the final and drive direct (using an NTE-37 PNP for AM Regulator) or piggyback on the rear panel as separate "bolt on" like the RFX75 kits and run power straight rom the power cord - no modulation added...Class C

But if you had the time - you can take the parts on the daughtercard and make up a Class AB bias scheme - you had the 150 ohm resistor on the main board (or whatever was used for Bias feed). And they supplied a 4004 and 914 diode for the TX or Bias - you picked. You soldered those for your choice of operation, one went for relay "Sense" and the other was used (if you needed SSB) for the Class of operation - the coil for the base bias side (in the instructions posted earlier, it's this coil you wound, in the photos above, it's a molded choke and you soldered the diode in series with it for SSB) - you used a 47 ohm 1W or 2W resistor ACROSS these two for the AB biasing (non adjust - you had to determine it by mA back at the test point in idle and used a fixed - I just dropped in a 47 ohm 1W carbon comp for this as default. - about 25~35mA - OR used the built in resistor and mount the choke on the main board's BASE lead - like shown in the photos above (Across Base to Ground) gave you Class C.

The wattage problem was the Final it replaced - you got more capacity but limitations were the drivers own ability to have enough power to fully drive the 2290 as a final - but SSB it was great and the NTE-37 seemed to handle it well enough. The other methods of external relay drive was more for their likening drive power for High-Drive amps - gave you 20~30 watts carrier but kept the final from being the last point on the chain and suffer the higher SWR fail rate - the 2290 was built more for high-SWR applications but was not indestructible - so if you used it to replace the final - it made it nearly bulletproof - but as an external driver - it still left the final vulnerable.

Bill Either did one for HR2510's to replace the MRF477 - seems the Class AB bias scheme worked well for the HR2510's.

The unique thing about this kit was it's width and height. As in the heat sink itself - oriented one way - the "height" gave you the vertical fins, and two holes to mount over the driver and final section (side to side top to bottom) - oriented another 90 degree way, the WIDTH of the heat sink was enough to mount it flush to the rear panel you just removed the daughtercard - slid out from the grooves. It had a cover bracket that was "U shaped" those holes were tapped to screw thru the rear panel from the inside into that U-bracket cover - you used the card as the template to drill two holes for the flange mounts - and used the U-bracket for the external rear panel mount of that driver amp.

IF you wanted to replace the final - The Pill itself mounted flush to the rear panel on the INSIDE - the rear heat sink sandwiched the rear panel to it using the threaded part thru the rear panel from the 2290. You also can, as I found out later, it wasn't necessary - the other two holes above and below the flange for the bracket - you didn't need it - you took off the 2290 from the heat sink and the flange mount itself was strong enough - since you sandwiched it all thru the rear-panel. The only thing I could think of when it came to the U bracket install was to keep the heat sink flat against the rear panel and add more metal to dissipate the heat - there were only two "fins" per side. but it was deep - about 4" so you needed clearance to use this setup. (The rear panel coax connector - well it was a tight fit but it worked...removing the U-bracket cover at least let you gain access to turn the knurl of the coax connector.)

The heat sink's Flange mounting was tapped all the way thru - so once the holes spaced for the 2290 got drilled - you turned it - the heatsink fins were horizontal - you mounted the card INSIDE the radio THRU the rear panel and into the heat sink flush and there were "tangs" set up that you could solder directly to the main PCB and another set to wire in the relay's TX voltage "lead" - you had two Disc caps 0.01 and 0.1uF and a RF choke to keep RF out and that is what you used to filter the Relay's coil power. So essentially this kit was a modulator or a driver amp setup...you sandwiched the 2290 to t rear panel - and the heat sink kept it flush and provided the surface area to take away the heat.

Now, to answer the 30 watt versus the 50~60 watt question was how you set up the kit

Using it for class AB - you kept the radios bias setup and removed parts from the daughtercard (actually just one and a jumper on the main PCB took it's place - you soldered in a hairpin - and installed / relocated a jumper (the relay is used but you had to obtain the NTE-37 to make this work (upgrade the AM Regulator)) and soldered in place - for Class C you kept the original too but moved the jumper so the relay would work with TX and power was sent direct from power connector thru relay as DC no audio.- so you could use it in Class C or Class AB - but whether two stage (as a final replacement) or the tri-stage (modulator or driver) gave you the various configs to make the wattage needs work for your setup.

Replacing the final gave you 15~20 watts carrier at the most - add to the radio gave you 25 ~30 watts seems like small potatoes these days, but back then it was the cats meow and novel use.

The major selling point was the bigger final - to replace the "smaller more limited" ones in the day.

It was more of a learning tool - you needed a lot of tooling, time and patience but what you got in return was some great experience.

:+> Andy <+:
 
I like the idea of close to 100 watts. And can be run off the trucks cb power port and no need to run a 10Ga. wire from the battery. THere would be less chances of theft also because if anyone looked in the window all they would see is a old Galaxy 33 or a old connex 3300. And it is all one unit.Then I take it you do not think this idea is crazy?
 
I don't...but unless you SSB, the bias stuff is a little trickier. The TX stuff will need a big part - like the NTE and you'll need to understand - that wattage stuff is pivotal. Too much drive you fry the AM regulator - too little and you barely swing.

You'll need the heat sink too. So don't forget that...IT won't hurt is you plan on self tapping screws - bolt on and done but if you want to fiddle with it, use nuts and bolts - it's just easier or tap the heat sink straight thru - just don't overtorque the screw then you'll have the elongated hole blues...
 
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I believe what Sonoma posted is my directions from the shiny metal forum that I put up years ago, haha, I was sitting here looking for it so I could share it.

I want the blueprints for that daughter board... I've been trying to find it for the Connex 4300HP so I could do this very project myself. And I'd like to get my hands on the one for the S980 as well... that'd be kinda fun.

I'm not top-self tech material, many here can probably hand me my butt but I'll say that in my opinion you'd be better off just adding in a AD203 to get you to 100w easily. I install a bunch of those boards and I think they're fairly decent for what they are if you don't put them in a hacked up radio. I'll be the first to say, yeah an external is better... But this "amp pill in a Galaxy" project is fun. When I did it back years ago, I did it in a Galaxy 33HML. I put the radio in my truck and went off to work, about mid day I put hooked it up and it was one more loud AZZ radio, very strong and very loud, clear too. The problem was you couldn't control it, the install is so crude that you really don't have anyway of keeping it at a constant. It'll get hot and start putting out less and less power. I had pics but somebody needed my computer more than I did and they broke in my house years ago and took it.

If my memory serves me correctly, I bought the plans off eBay and then uploaded them to ole shiny and shared with the world. I believe Mad Scientist was one of the first guys to thank me for that... I have those plans somewhere still if anyone really wants them, I'll try to dig them up and upload them.
 
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I do not remember where I got that info , it has been too long ago.
Porkchop you may have been the one that posted it.. I know it was not as easy to do as I 1st thought way back then. had to keep playing around with all then feeds to the pill to get it where I had it. did not want to kill the pill so just left it putting out less than was claimed to do.. Wildrat just joined the forum a week ago. he may have some thing on it if he shows back up. the pictures that came with the mod I just can not find them. that was 3 or 4 computers ago and more hard drives than that since they use to go out fairly often.
 
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I can tell you by the wording, I wrote that. It’s posted on the shiny metal site still to this day unless ole FM has deleted it. And that’s possible considering how many times I got banned and joined again under another name to tick him off and got banned again, haha.

Low_Boy, I’ll dig through my notebooks and stuff and see if I can find it. Seems like several weeks ago I ran across it and I’d be happy to post it up for you, bro.

Back then I was all about snipping and clipping whatever out a radio just to see a meter swing to a higher reading, so that might be why you couldn’t get the same numbers that I posted. Today, I’m older and wiser (or pretend to be) and I don’t clip things out of radios. So I’m kinda curious now too what that will yield and if it can be tamed any at all. So I’ll try to find it and get it posted. It has pics and detailed (somewhat) instructions
 
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Alrighty, I found it and here it is, freshly scanned to a PDF for your viewing pleasure. The pictures are kinda faded, I did get this about 15 or so years ago and at one time all my radio stuff was in storage. I don't believe that ProClassRadio is in business anymore but if they are, well, I just jacked ya stuff buddy and shared it again...
 

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thanks Porkchop, that thing shows 2003 when it was put out. that paper has faded a lot but still readable. I have not seen this for sale on any sites for years now. i noticed last night 88radio has the kl 203 mosfet board for sale for 50.00 and it mounts in the speaker location of a radio.. that would much cheaper that putting a 2290 on the back of the case of a radio.. I never use the internal speaker of a radio so not a bad price for a mosfet output section. I have one of those boards I tried in a cobra 29LTD a few years ago and pulled it out when I sold the radio. guess I should try it again in another radio for fun. 4 520 or 13n10 mosfets are very cheap so would not be a problem if it blows up.
take care my friend.
 
6BE688CC-E8D3-46D0-B33F-D11B4A334C0C.jpeg C8BDA7E5-52A9-400F-BD77-0FBDC1FA9934.jpeg Well I sell a lot of those, installed. I can tell you I believe it uses the RM3 (?) mosfet and when those go out, the other two you listed won’t give you the same output. It’ll be close but it won’t be exactly the same. It’s sold under the name AD-203 and it’s a nice little board to add in. I agree, it’s a more stable option than putting the 2290/2879 in the way those directions say.

The biggest issue I have with that board is the guys that want every last drop out it possible. I do as they ask, they’re paying, and what you’ll see is the power dropping off the hotter it gets. Now if you can keep it cool, I assume it’d be constant but I haven’t tried adding any extra cooling to it. Just like the 2290 mod, it will make your radio loud, almost too loud. It’s best put in a radio that has absolutely no modifications or twisting and tweaking done to it.

I got that mod by email and printed that out years ago and stuck it in my notebook, it is faded. The computer the original copy was on, someone was awesome and broke into my house and stole it, so the digital copy is long gone. I tried though!

I’ve put that 203 in a metric ton of Cobra’s and Uniden radios. Clipped, I get about 120 or so out of it. Never tried it in a Ranger chassis though, got me curious too. The PCN-60 will make just about whatever you put it in do like a Galaxy with some modding and the BDW famous NPC mod. That’s about 10-12 average watts and about 40 peak.
 
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I'm not sure of the resistor number because I'm at work but there is a resistor you could change on there to get a bit more power out of it I believe it's a 5-watt resistor.
 
Yea on the AD203 you can clip that big resistor, that’s what I meant when I said clipped in a previous post. I don’t suggest doing that. I don’t think the gain is worth it, you just stress that amp in my opinion
 

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