Heathkit SB-220 Amp. Repair

[Unit 194]

Can anybody recommend a tech. who does repairs on the Heathkit SB-220?

 

[mrgumby]

Ham Rf Tube Amplifier Repair

Ham Rf Tube Linear Amplifier Repair

amprepairguy.com

 

[nomadradio]

That's a cool link. What I want to know is his 'secret sauce' for shipping a SB-220 without damage. The chassis metal does not have the tensile strength to support the heavy HV transformer under any kind of handling shock. We have seen the chassis deck bent under that transformer in nearly every SB220 we see that gets shipped. The worst one had severed the chassis deck all along the rear panel. Frequently it deforms enough to interfere with one circuit breaker and crack its case. When the factory sold the assembled version, it arrived in three cartons. One for the amplifier, one for the tubes and one for the HV transformer. The transformer had plugs on every wire. You bolted and plugged it in when it arrived. But Heathkit was not foolish enough to ship it with the transformer bolted to the chassis deck. A look inside a Henry Radio amplifier reveals metal five or more times that thickness under their HV transformers. But you can ship their amps assembled. That's why.

If he has worked out a way to have you ship a SB 220/221 to him without damage, that would be real news.

73

 

[Unit 194]

Ham Rf Tube Amplifier Repair

Ham Rf Tube Linear Amplifier Repair

amprepairguy.com

From the website. "Work rendered for radio operators only." Translation: Amateur radio operators only. I spoke to the gentleman and he doesn't do amp. repairs for CB'ers.

 

[Unit 194]

That's a cool link. What I want to know is his 'secret sauce' for shipping a SB-220 without damage. The chassis metal does not have the tensile strength to support the heavy HV transformer under any kind of handling shock. We have seen the chassis deck bent under that transformer in nearly every SB220 we see that gets shipped. The worst one had severed the chassis deck all along the rear panel. Frequently it deforms enough to interfere with one circuit breaker and crack its case. When the factory sold the assembled version, it arrived in three cartons. One for the amplifier, one for the tubes and one for the HV transformer. The transformer had plugs on every wire. You bolted and plugged it in when it arrived. But Heathkit was not foolish enough to ship it with the transformer bolted to the chassis deck. A look inside a Henry Radio amplifier reveals metal five or more times that thickness under their HV transformers. But you can ship their amps assembled. That's why.

If he has worked out a way to have you ship a SB 220/221 to him without damage, that would be real news.

73

I shipped a few back in the day and they always had to be double boxed with my fingers crossed that they would make it in one piece. Somebody once told me that the proper way to ship them is in a wooden box/crate.

 

[BayouRadioAmplifier]

I repair these beasts. problems I found.
do the tubes get red hot after keying up?
zener diode ZD1 shorted. ?? No RF out? maybe resistor R3 is blown open.
only half power? RFC-4 or 5 open. need to ground the grids directly.

located in SE Louisiana.