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Wow, I been testing the output through my antenna the whole time, my SWR is lowest on 26.885 mhz (1.1) and it's a 1.8 on channel 40 (haven't taken the time to readjust it). I decided to check it on my dummy load instead. Unholy crap, this radio is doing 60w PEP. Decided to try the output on the...

Got the new MaxMod installed along with a new AF regulator (just to be on the safe side). So far so good. Gonna hammer on it later this evening with the locals. I'll give an update later.

Decided to monitor the MaxMod voltages before and during this issue. Passthrough voltages: Receive Base - 13.23v Collector - 6.57v Emitter - 13.71v Transmit (Hi power - 10w carrier) Base - 12.12v Collector - 5.87v Emitter - 12.86 Collector increases to over 6v+ when the Passthrough starts...

I thought this was a new MaxMod he had put in here before he got it to me. When I got it, the MaxMod wasn't tightened down firmly, there was a gap big enough to slip just the tip of my ceramic tuning screwdriver in, just the very tip, and the regulator would actually move side to side with...

Current draw: Idle, receiving with volume all the way down - .25 amps. Transmit, carrier - 1.99 amps. Lo power, 3w carrier. Transmit, modulation - 3.45 amps Transmit, carrier - 3.65 amps. Hi power 10w carrier. Transmit, modulation - 4.88 amps When the power drops and gradually starts...

Well, tried using a zener across the driver (that's the only one the gate voltage climbs up with when it does this issue), no go, still same result. Left the zener on the driver and adjusted current draw like Nomad stated above (not his last post, but his post before that one) to 20ma for the...

I'll try the zener first, then reduce the bias if need be.

Haven't taken care of this querk yet, but I did speak to a few of my locals over the phone and asked them to describe what they saw on their meters and what they heard the whole time I was conversing. They all claimed the same identical thing. My signal (carrier) was very strong and the audio...

Guess I'll throw some on. I just checked this radio out over the air after replacing Mosfets and a few caps. Everyone says it's loud and strong, but when the watt meter jumps down to 43w and starts gradually creeping back up they said my audio gets weak and creeps back up. I checked around for...

I always fully recap any radio over 40yrs old. I've always been told that 10v caps last about 15 to 20 years, and so on with other values. 10v - 15 to 20 years 16v - 20 to 25 years 25v - 30 to 35 years 35v - 40 to 45 years 50v - 55 to 60 years Most of the older radios have 10v, 16v and 50v...

Got a General Lee on the desk for an issue that reminds me of something heating up. The radio has a mosfet (520) driver and two mosfet (520) finals. Radio is not stressed out in any way, runs cool, receives great, transmit great, just an odd issue. The radio does 53w Pep, everyone says it...

Correct, I worded it incorrectly.

Not sure, should be mica. I think the ceramic insulators can create capacitance through the transistors.

The following pic is one of many instances I run across on my desk. Maxing these radios out just to see that swing on that watt meter is damaging parts due to excessive heat buildup. Guys/gals, you don't have to stress these radios out. You don't need any swing mods, regulator mods, etc... Just...

Try increasing final bias to 35ma up to 55ma, see what you get. I'm with Cable on this, every 1969 I've ever seen runs best around 50ma. Your 138 came factory with the 1307 that needs only around 15ma, whereas you're now using a 1969 which needs more current to operate at its max potential...

I was thinking of another radio I was helping someone out with on this site, got the threads mixed up. Sorry bout that, my bad.

VCO Buffers, carrier oscillators, driver/final bias drifting, RF stage not aligned properly. All these will affect output. Do a complete alignment, paying close attention to results. Like nomad said, if any of those silver cans are topped out (core flush with top) or bottomed out (core flush...

How bout sideband output? I'm sure you've already recapped (or had it recapped) right?

No problem Krazy, Hope to hear you in skipland sometime. On CB I hang on channel 40 AM, 29 AM, sometimes channel 1 AM and I go by 351 around the Carolinas. Peace...

I see a "simple swing" mod also in the top pic above. This simple swing mod I see no problem with, I use it myself also at times. But in order to go back factory I would remove it. The one I'm referring to is located right in front of VR13 (AM HI deadkey adjustment). It's marked as R238...