I just got a kenwood 450sat thinking power supply was no big deal,I'd build one.when I looked on this site for schematic what I found was regulated supplies.  The specks for the radio says it will operate on 12 to 16 volts so why all the fuss to regulate? Is there a voltage bounce going from transmit to rec?



 

yup both upper and lower

Threr'd be no fun in someone else fixing it.I'm new to ham but I have allot of experience restoring old radios.I had over 300 tube radios at height of my illness.I'm allot better now,and only have a few. To me its more fun to puzzle a thing out and maby learn sonething new.Once a radio is working,it goes on the shelf.I enjoy the pursuit more than the end.I just got a kenwood 450sat to use if I just want to get on the air.Theres a chart in manual showing resistances at tube sockets.I haven't done that yet.I'll take a look at the high value resistors.I replaced a couple of caps,but its far from being re-capped. 

easy enough to look I got some,and all the screws are out.

I've been fooling around with the kenwood 520 for a while.it receives and transmits for a while.The drake tr3,a real boat anchor spends most of its time waiting for tubes not much fun in that.It receives a little with vfo having little affect.Manual says just because a tube checks good doesn't mean it will work.So 2 or 3 at a time it gets new tubes.I guess I'll have to dust off signal generator if that doesn't work.300 watts would be great.

Ok,I warmed it up and hv is ok when dead.another clue,it shows power in tune and cw. dead in sideband only,time for more reading.

thanks for all your help,I got a dummy load and got antenna matching very close.replaced all 3 tubes,and neutralized finals.Replaced hv cap feeding finals.set now puts out 100+ watts and getting good reports yea!After a good while of listening and butting in all output dies,didn't think to look at high voltage.I'll do that next.    my suspicion is out put transistor on rf board I think it was #10.thought I might find a glue on heat sink for fun,but then will that act like an antenna?  Just what is the bad thing that happens when transmitter is keyed with no antenna .set came from ebay.

thanks for your input. The dipole is roughly 80 meter,and I can get swr down pretty low with tuner on 80 meter band.I was told it would work better with a ladder line.I'm leaning t words adding shorter lengths to make it a fan.Probably will make a trapped 40 80 next.I'll get a analyzer to get lengths more correct .the 450s sounds like a good radio.Power supply isn't a big deal. 

or for a little more money,a ts450s with auto tuner?So many radios,so little time.

Ok the 520 seams to be working now.My brain is having trouble with tuning it.Question is would the 140s be any easier to use ?

Thanks for all your help.new clue: when trying to transmit power dropped off quickly.replaced driver with no change,although tubes tested fine but allot of difference ,a new pair has every thing working.I put together a dummy load and used for neutralization.I dont trust my antique vtvm so I used a fluke set on milli volts.hope thats close enough,I adjusted cap for a lowest readin.g of 2.4 across dummy.now to learn to tune this thing. from all my reading it sounds like a antenna analyzer would help getting wire lengths right. I'm leaning t words fan dipole.I bought a piece of ladder line 20 ft long reading up on it says it should be at least 30 ft. I got the heavy coax,and I,m reluctant to cut it,in case my wife lets me put tower up. might have to give her new kitchen first.Should be on the air tonight.
 

I had one of these years ago,I think I sold it for 150.My 1991 guide book says its worth 800-1200 depending on model,how complete working? its an easy fix?.It's all about what its worth to you. I'd buy it for 75-100.

I was afraid of that,I was on 80 meters when it was best.So I stay on 80 or drop with a ladder line

looks like hayseed has just what the old set needs,way better than adding three new caps under the chassis.thanks.

after cleaning and deox radio works pretty good. waiting for finals parts .issue is there's no meter movement in tune,I don't have a dummy load yet and I'm new at tuning,crippled by dyslexia,going from schematic to radio backwards! I checked resistors on high voltage board finding one that was way off,but still no change after replacing.Don't know if its a big deal,when I can tune into dummy while in transmit. hard on the tubes.I thought I'd get the giant print schematic and go from there,thought I'd stay off the air till I can tune it better. second issue is antennas.ask 5 hams and I get 8 different best for the beginner.What I put up is a dipole,130 feet center fed with coax (the fat stuff)no ballun .I have a fine tuner,and no matter what I do swr is pretty high.logic tells me I need a ballun to get it anywhere near 50 ohms.