[Amps] RENEGADE CUSTOM 300B

[JAMES SMITH]

(Redirected by "Will Matney" <craxd1 at ezwv.com>)
James, see below;

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REGARDING A NEWLY ACQUIRED 6 METER 
AMP THAT COVERS 1.8 TO 53 MHZ BUT IS NOT WORKING TO IT'S FULLEST 
EXTENT. I HAVE SOME KNOWLEDGE BUT AM STILL A AMATUER. IT WAS TAKEN TO A HAM REPAIR SHOP AND THE TECH WAS ABLE TO TELL ME THAT THE PROBLEM WAS 
PROBABLY IN THE TANK PORTION OF THIS AMPLIFIER BUT COULDN'T TELL WHAT EXACTLY WAS WRONG BECAUSE OF THE LACK OF SCHEMATICS.

They needed schematics for a tank circuit?

 IT IS A VERY SIMPLE AMPLIFIER USING 2 3-500Z'S. IT ONLY PUTS OUT 400 WATTS PEP AND FROM WHAT OTHERS TELL ME IT SHOULD PRODUCE 1200-1500 WATTS PEP WITH APPROXIMATELY 100-150 WATTS OF DRIVE. 

That's about right. First, what is the SWR between the transceiver and the amp? Next, on each band, where does the tune and load capacitors set at, about mid way or fully meshed when tuned?

IM NOT SURE IF IT IS A NORMAL CONDITION BUT IT ARC'S ACROSS THE TUNING CAPS WHEN UNKEYED LIKE STORED VOLTAGE.

No that's not normal. I would check the parasitic supressors on the top of each tube. They should be something like two 100 ohm 2 watts in parallel with a coil.

 I CAN'T SEE THE COLORS OR THE RESISTORS THAT GO TO THE TOP OF THE TUBES I WAS JUST GOING TO START REPLACING THINGS BUT FIGURED THAT IF SOMEONE MIGHT BE ABLE TO LEAD ME IN THE RIGHT DIRECTION IT WOULD MAKE THINGS A LOT LESS TIME CONSUMING. 

If there's 2 resistors on each tube, most likely they're 100 ohm 2 watt. If only one, a possibility could be 47 ohm 2 watt. That would be kinda undersized though for two 3-500Z's.

THE TECH DID TEST THE TUBE'S THEY TESTED AT 90-95%. ALTHOUGH I DID HAVE ANOTHER BRAND NEW SET I STUCK IN JUST IN CASE AND STILL THE SAME. I DO PLAN ON RE-WIRING IT AS SOON AS I CAN BECAUSE SOME OF THE SOLDER JOINTS LOOKS PRETTY BAD. IT HAS TWO TRANSFORMERS AND IM THINKING THAT ITS A GOOD POSSIBILITY THAT ONE IS GOING BAD AND TH
 AT VOLTAGE SUPPLY IS AN ISSUE. 

What is the plate voltage? Does the amp have a voltmeter to check it? Also, if it does, can you read the plate current? If a transformer were going bad it would either be shorted to where it would blow a fuse pretty quick or run really hot and smoke plus hum loudly. If one were open, it wouldn't have any voltage coming out of it at all. I imagine one is the plate transformer, and the other is for the filaments. I don't think you have anything wrong in the transformer department, maybe in the rectfier circuit or filters. If the tubes light up, then the filament transformer is okay. If you have high voltage at the right amount, then that transformer is okay. Without either, you wouldn't have even see 400 watts.

ONE SUPPLIESW VOLTAGE TO THE TOP OF THE TUBES AND THE OTHER SUPPLIES VOLTAGE TO THE BOTTOM OF THE TUBES. THREE OF THE TUBES ARE SHORTED TO CHASSIS GROUND. IT ALSO HAS A BANDCOIL AND NOT A SWITCH TO GO FROM 6, 10, 12, 15, 20, 40, 80 METERS SO YOU CAN REALLY 
FINE TUNE. IF YOU COULD HELP I WOULD BE VERY GREATFUL. I ALSO UNDERSTAND 
THAT THEY ARE VERY DANGEROUS TO WORK ON IF NOT EXPERIENCED. I KNOW 
BETTER THAN TO STICK MY FINGERS IN UNLESS IT IS DISCHARGED. IF YOU COULD 
GIVE ME A REFERENCE VOLTAGE AT A COUPLE OF PLACES I COULD CHECK THE 
VOLTAGES AND REFER BACK TO YOU FOR FURTHER ASSISTANCE. 

3-500Z's run anywhere from +2500 to +3000 Vdc, and the filaments are 5 Vac if I recall.

OR I COULD TAKE 
PICTURES AND POST THEM WITH AN E-MAIL SO YOU COULD SEE THE DESIGN. OR IF YOU CAN'T HELP ME MAYBE YOU CAN REFER ME TO A REPAIR SHOP THAT CAN 
DEFINATELY FIX THE THING. DUE TO IT'S WEIGHT I'D RATHER NOT SHIP IT THOUGH. 
ANY HELP WOULD BE GREATLY APPRECIATED. KG6NLB at YAHOO.COM JAMES SMITH @ 209-329-3826 YOU MAY CALL IF IT WILL BE EASIER OVER THE PHONE ALSO.


First thing I'd do is go over any solder joint that looks to be cold soldered. Clean the relay contacts with a contact burnisher. GC Electronics makes these little flexible files. You may be able to use a piece of really fine sand paper like 400 grit. A few passes on each contact surface is all it takes. If the SWR is high between the transceiver and the amp, that will kill the power too..


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Best,

Will