The AM Forum

I've had this radio on my bench for months I've replace all of the electrolytic caps and the SR but now I'm not sure I've replaced them correctly. I used a single 1n4007 to replace SR1 thru SR4 but I see SR1 and SR2 was a dual section. Will two 1n4007 work to replace this two section rectifier and is the 1n4007 the correct part?

Thanks,

Bob

 

Watts the voltage??
 and current??

klc

That's the problem I can't find any specs for any of them, on the schematic or the parts list. I tossed the ones I took out so can't look at them. I was hoping someone else had replaced them and could advise me.

Bob

SR 1 & 2 are used to set the bias voltage to 8 volts.  Replace them with a 1N5344 (8.2 volt 5 watt) zener.

Parallel existing selenium rectifiers with the modern silicon units for original look without the scent.

The new diodes have less forward voltage drop than the finned antiques and will put them into retirement.

No need to remove the elder statesmen.

On my 300 (same rig) I left the bias ones alone and changed the others with some 1n5408s I had lying around.   I left the old SR"s in place for original look.

C

I hope they never short.  If they do, and I have seen numerous examples, they stink up the place.  And if you replaced the others, how does these two make for an orginal look?

It's a friggin' Globe Chump. Not hardly a high-end piece when new and not collectable. Who is looking under the chassis anyway?  I don't when I'm on the air. ;)

They worked for 63 years so far with out failure on both my champs.  The ones for the half wave supply on the relay control did fail but did not smoke. A simple 5408 and its back on the air.  The 5408s are under the fins of the old SR's.   I like to keep things orginal.

And 75A-4s went for $275.00 in the 80s.

Someday that Globe Champ might be highly sought after. Stranger things have happened.

All I know is they can sound really nice.. axe those 'couplates'..
and they look good with a pal..

And the fumes are highly toxic. They should be removed and disposed of in an environmentally safe manner. Selenium rectifiers manufactured in the 50's and 60's have long exceeded their typical life span for safe use.

"Original look" with disregard for safety, is not a good road to travel.

Blah... Half this stuff is filled with PCB oil including the cap in that Champ.

C

Clark, what Pete is telling you is the fumes from burning Selenium is highly toxic and can cause permanent breathing problems depending on the amount you take in.  Don't risk it in an enclosed room.

Pete,

    I'd love to chase you around a large parking lot driving a Crown Victoria loaded to the gills with selenium rectifiers.

Dave.

Will the Crown Victoria be in the typical full flames from a rear-end collision? Crown Vic's and Ford Pinto's are like the bogeymen of cars.

Two quotes come to mind:
"I am invincible" James Bond - Goldeneye
"Do you want to live forever" - Conan the Barbarian

Yes. I will be wearing a hockey mask also.

Let's get Selena Dione to sing the Selenium theme song.

But then it won't be "original."  ::)  

This original stuff is a bunch baloney anyway. If you've touched a soldering iron to the chassis, it's no longer original. On top of that, the Chump was original in the 1950s and early 60's as a low priced medium power transmitter for use when all we had on the bands was AM and CW (with SSB and RTTY just coming along). It was designed to run on 110 VAC. By plugging it into the 120/130 outlets of today, you've just gone beyond original. By connecting it to an antenna made after 1965, you've gone beyond original. Today, the Chump (any Chump) is no longer original, no matter what parts you leave in or take out. Its time has passed.

The craziest example I've seen of this silly original mindset run wild was years ago. I had a conversation with a guy on 40 meters about his ART-13. He proudly proclaimed he would never use it with anything but a carbon mic, since THAT was original. When I asked him if he was going to only use it in a B-17 to contact the Army Air Corps, since THAT was original, he suddenly had to QRT. What a load!

I totally agree! I have not found a piece of tube equipment that I couldn't make better or safer in some way. Especially safer. It is a wonder there were not more electrocution fatalities back then. With fuses in the neutral leg, no line ground, no GFI's. The only thing that is sacred to me is the front panel past that I make it better. We aren't going to keep these rigs going by preserving old crap. Make it better and document what you did.

Too much of it comes from flawed thinking that these radios will be worth something like vintage cars. Not so. Adjusting for inflation, most of this stuff is not worth any more than it was new. The market demand is just not there. If some want to keep their stuff original, fine. I don't really care. Just please do not act like you are doing something special or significant.

In 1954 an assembled  Johnson Ranger cost $250. Adjusted for inflation it would be $2,134 today!  I think most of this stuff is a loss. We collect it because we want to not for the value.

True if it were purchased new. I bought many of my old radios before they were cool.

" When I asked him if he was going to only use it in a B-17 to contact the Army Air Corps, since THAT was original, he suddenly had to QRT "

S,

Maybee he was a NAVY man who drove a PBY.


klc

I'm sure you are centering your retirement income around all those "valuable" radios.   ;D

Also, you have to include your time in that equation. Going to tests, doing repairs and rest only takes away from any perceived value, even if you got the the radios free. It's likely you could make more working at McDonalds per hour than buying/selling and working on radios.

He was too young to have been in WWII.

I get the original thing up to a point (vintage knobs, not painting the R390 neon green) but I draw the line at stuffing capacitors.

The extreme seems to be found in the Collins fanatics.  Somewhere in the past 15 years or so there's an ER article by some ham in Arkansas about how he restored is KW1 to exactly the way it was shipped from Collins, because the original Collins engineering was perfection and improvement was impossible.  He may not have put it that way but that seemed to be his attitude.  So he ran the clipper, the splatter filter, maybe even the 872s, can't remember, but he also spent years researching the paint and managed to find the old man in Iowa who used to work in the Collins paint room so he could find out exactly how the rig had been painted and got the company that supplied the original paint to mix him a batch.  A photo in the article showed this fellow next to his KW1, looking unhappy.  I think if you are that obsessive, you're going to be miserable most of the time.

We all know of some hams whose interest/activity with the vintage equipment and ham radio seem to revolve around buying and selling and wheeling and dealing. These types seem to drive a lot of this extreme thinking.

But you don't hear these guys on the air all that often, especially since many of the on air swap nets have gone away.

Its when they try and impose their own personal views on others that it gets silly.

Al VE3AJM

It's a shame everyone can't be normal like we are!!!  ;D ;D ;D

Concerning Pintos and Crown Victorias, they only go boom once they're hit.  Otherwise, they're just as safe as anything else. [And this from growing up around bodyshops where a lot of cars should've been totalled and weren't.]  ;)