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Something I never got around to experimenting with was what would the FDA24N40F swapped FET (Palomar FET 450HD in this case) amplifier do with 24V or even 50V supply voltage? The FDA24N40F is a 400V mosfet. Someone try it and share. The parts are cheap, who cares if they blow up, $10 or less...

This is a wild discussion. I never bothered with the RM3 or any of the RM amplifiers period, but now you got me interested. These are $68 and will output 100W? Where do you buy one for $68? Sounds like a neat experiment. IRF9530 is a P Channel Mosfet in TO-220B package, I would say, that's...

Haha someone got that from me. I am the one who originally put the FDA24N40F in a 4x amp back in like 2010. I only told a few people. Yes they do work. Within 5-10% of the correct power output and they are like $3 each. $1 each if you buy 1000. I think I may even have some pictures to...

Really really old. But if you already had the board for it, and wanted to assemble it, you can use the HG Semi MRF454 transistors. If you want to build a 2SC2879 based amp, start with a design that was meant for the 2SC2879, as turns ratios on the transformers and all tuning circuit...

That price is not bad. Seem ole W8JI don't like the Johnson Matchbox's that much. But as a pretty smart friend told me, W8JI, is a work in progress. So you take it with a grain of salt, and understand it's HIS opinion. For most folks, they probably work fine, are they the "cat's meow" of...

Correct. After the 9/11/2001 attack on the USA, I always have said that the problem with this Country is the Freedom itself. It allows everyone to only worry about going out, or going fishing, or the latest fashion trend, or the latest gadget, whilst all along not learning a single thing about...

I feel you on that. I know that Chip Capacitors can be just fine, and low tolerances, but damn does it just look cheap compared to the 1000pf Semco's, which you probably can't even get anymore, maybe Made in China clones of them... I know the "experienced" or "pro" builders don't really use...

I think hands down the old school big (2500 watts?) Palstar Tuner is the way to go. Can't remember the model number, those are built like a tank, you'll never need another Tuner unless you go big. I think it was AT2K? something like that. I looked at them years ago, was set on purchasing one...

That's just sad. I wish someone would buy out Texas Star and build the damn things right, and maybe build something without those ridiculous push button switches. It's sad to see Texas Star, a staple of the CB Hobby for as long as I can remember (been doing it 30 years) lack innovation, and on...

How old is this amp? Did you buy it new? The newest Texas Star amplifiers (the ones they are selling now) I am pretty sure come with the Fake Toshiba's already in them. The regular HG 2SC2879 (not the C version) will replace those, however if they've changed the tuning to accommodate the Fake...

Hmmm.. I have one like this, been a little over a year since I looked in it, so I don't remember details of troubleshooting it. Mine is a newer one, with the "Cobra" I think it says on it PLL chip. The PLL chip is dead. Rest of the radio is great condition. I just kept it around for parts or...

A side note, it's a whole lot cheaper to make the modern day SMD parts radios. They are cheaper altogether to build than anything from the past. IF, you were to build a radio, like they did 30 years ago, in todays world, it would exponentially more expensive. Even the modern Galaxy (RCI...

Absolutely. Modern Cobra is a joke. I was around in the Uniden glory days, if I had only known how things would end up, I would have bought all the old school 148's, Grants, 29's, PC68/78/122, etc that I could get my hands on for later down the road when everything went to shit. I was just...

About the saying about "Made in Japan Garbage in the 70's"... Vintage HiFi is a world full of snobby, often rich, "couch quarterback" types, with huge ego's and very nastily opinionated folks. Those old Japan HiFi units were supreme, yes. No argument there. About the SAYING from the 70's. I...

Update on this. After closer look with the scope probing around, it appears that I have proper drive signal, Bias voltage, and switching (RX/TX). The problem appears to be that if you replace the RD16HHF1 with a IRF520, you have to retune the output coils. I did not want to mess with that...

Yes all same. The difference may be, and I couldn't prove it one way or another because pretty sure all my Grant's are Made in Philippines. I have heard that the later model LT's may have some issues, but no way to confirm that, pretty sure I have an older one. None of the Grant LT's were...

LOL. Patiently waiting to hear the differences between a Grant XL and a Grant LT.... You do know it's the same exact radio, same board, same parts, but has backlit knobs and a front mic jack, and a DSC (Dynamic Squelch Control add in board from factory)? Same everything as Grant XL (I own a XL...

I was looking at this thread, my Uniden Grant LT saw it and said, "that's dumb". LOL

I have a 980SSB that worked fine, one night I think the desk mic may have accidentally got bumped and locked into transmit, blowing the RD16HHF1 fet eventually. The mic is a old Turner Super Sidekick, has that sliding lock switch that can be troublesome if you bump the mic around. So this...

Reading back over this, sounds like maybe you needed the full amp schematic, I do not have that. The one I posted is just a quick drawing of the "Regulated" Bias circuit used in the later model Elite series Palomar amps. A full schematic might be found by searching heavily with Google or...