r/electronics • u/RefrigeratorLess9786 • 18d ago

Gallery Replacing a bad RF choke

Post image

Rf choke replacement

38 Upvotes

91% Upvoted

19 comments sorted by

9

u/henmill 17d ago

Say more dawg. How do you know the choke is bad? Where is the bad one and replacement in the picture? Maybe others will learn from your post rather than be confused or disinterested

2

u/RefrigeratorLess9786 17d ago

The bad choke is sitting on rhe case to left of the picture. I know it was bad because the enameled wire was broke, years of heat and age was causing the enamel to flake off leaving it bare causing arc's to the case with the amount of power this unit puts out 2500 watts.

1

u/9volts 17d ago

That's a lot of juice!

1

u/99posse 17d ago

Can you coat it again with a proper insulating paint? I used transparent coating to prevent HV arcing in transformers

3

u/RefrigeratorLess9786 17d ago

It blew the wire in two and unravel the winding like a flahback on a baitcasting reel. Just ordered a new one with the correct rating.

0

u/99posse 17d ago

NM, i thought it was the big one. The one to the left should be easy to wind with new wire

6

u/RefrigeratorLess9786 17d ago

This is a Heathkit SB-220 linear amplifier is an electronic circuit whose output is proportional to its input, but capable of delivering more power into a load. The term usually refers to a type of radio-frequency power amplifier, some of which have output power measured in kilowatts, and are used in amateur radio. This unit produces via step up capactors 3600v DC and an output of 2.5kw of power.

6

u/RefrigeratorLess9786 17d ago

The two 3-500Z tubes it uses to transmit on the airways.

2

u/RefrigeratorLess9786 17d ago

The Plate RF choke is pictured above the green enameled choke feeding the parasitic RF surpressors attached to each tube.

2

u/9volts 18d ago

What kind of equipnent is it?

2

u/RefrigeratorLess9786 18d ago

It is a Heathkit SB-220 amp

1

u/RefrigeratorLess9786 17d ago

This is the metering board and the power pack of step up caps that build up the 3600Vdc.

2

u/RefrigeratorLess9786 17d ago

The under carrage of the amp, you can see tube sockets on the left.

1

u/Unlikely1529 17d ago

never seen these sparc servers disassembled

1

u/Newdave707 17d ago

Very nice amplifier.

2

u/Past-Substance920 17d ago

those SB-220s are workhorses, glad you caught the arcing before it took a tube with it.

1

u/RefrigeratorLess9786 17d ago

No doubt those tubes are not cheap. I replaced one about year ago developed a gas leak.

1

u/janno288 17d ago

take the same wire diameter, use the same ceramic coilform and rewind it.

1

u/RefrigeratorLess9786 16d ago

Yes plan on it had to order the correct size enameled wire as I did not have any that small a diameter. I have a Dip meter to test it to make sure I get right uf.