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Thanks! Dave

Sorry for the noise, I found it on here after a little bit of searching, 'zactly what I needed, thanks! Dave

Does anyone have the schematic for the old version, with the dimensions? I have an old P500 from back in the late 60's in a pile, I wanna rebuild it and stick it up on the top of my tower. Dave

I know this is an old thread, but my message is along these lines... I have an old President Lincoln (original version, Euro import). Single MRF477 final. I can get it to do about 20 w SSB. On AM it runs best about 3-4w key w/25w pep modulated. When I look at it on the scope, I can see the mod...

FM bandwidth is 2x the highest mod freq (3khz or less in most cases) + 2x the deviation (typically 5khz). All of my repeaters on the ham bands are 16khz wide because of that. I wasn't as much concerned about occupied bandwidth as I was just trying to establish a "hangout" channel on CB for FM...

Wasn't sure how to word this...is there a "call channel" folks use for FM operations, within the legal 40 channel range? I've not read anything about one, other than one that's out of band. I saw a few folks say they had use channel 1 in the past, maybe that's a good start. If those with FM can...

Turns out the LM324 is also used for muting the detected AM audio, and had a bad section. I replaced it, and all is well. Boy, this radio is a mix of several other rigs...some that I still haven't found :-)

One little bit I just stumbled upon while looking at other radios' schematics...the Connex 4300 looks very similar in the detector & discriminator circuits, including the quad op-amp for agc and a final AM rx audio amp/buffer. Digging into the a bit more, now. Dave

Sure seems that way. I've traced detected AM rx audio around the board, found some similarities in how it's muted when the mode is switched to FM. Worked my way through the board last night and am at the lm324 now. I suspect that's just AGC. Since the S-meter is responding well and sensitivity...

Thanks for those links. I had found all but the last one, no schematic seems to exist on the web...at least, not that I can find :-(. I've compared it to every schematic I could find, but nothing seems even similar. I'll keep digging, if anyone out there has an idea on a schematic, I'd...

I have a SuperStar SS-3000HP that I've struck out finding the schematic for. The board is EPT300010A.AM rx audio, almost none. The RX is working well, all the way through the rx to the detector, S-meter shows good sensitivity. FM mode works fine, great rx audio. Seems to be something from the...

Thanks guys! Dave

Where have y'all found to be a good source of non-fake IRF-520 mosfets? I got a batch of fakies from Amazon that were biasing on hard at 2.5v, and become easily saturated with low drive. 70ma idle current happens about 2.2v. Tnx, Dave

Thanks, great info. I felt like there was something to be had there, and was pretty sure someone like you had been there long before me :-) I got started in repairing / modding this stuff back at a couple of shops in the mid-70's. Over the last 35 years or so (until retirement), my "real job"...

Hi Mike, I have a full shop with everything needed, just never tried to mod this final setup for more power. I found the gain on one of the 2312's is way down, no leaky, but on it's way out. Going to make some changes on the PA. I'll be working on that some more, tonight. Still wondering...

Another, but unrelated, question. Is anyone aware of an improved modulator over the 2SB745Y used in this radio? Dave

Hi Mike, this is a dual final radio. Tnx Dave

An amp is not a problem, but I see where these were typically doing 40+ pep, trying to figure out why this one doesn't. I did check it with only one final connected at the time, one is doing most of the work, the other has low output. Going to sub in another pair and see what happens.

A little bit of an update..I was looking into this more last night and noticed it's probably making as much dead key as it should. RF power on the board will go up to about 12 watts or so, unmodulated. With the carrier at 3 to 5 watts, it'll make about 20 watts PEP modulated. I sub'd in another...

I got hold of an old Ranger 6300F (not the TB, -25, or -150), running a pair of 2312's in the finals, and a 2166 in the driver. It's working fine, pep about 20 watts. I think I remember folks talking about them doing more like 45-50 watts pep, but maybe my memory isn't correct. It's pretty much...