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> Radyne (fw5) Ultrasonic Welder Repair, TB5-2500 tube circuit issues
gremlinsa
Posted: January 05, 2018 02:01 pm
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So I've picked up this reputation of been able to fix just about anything with 'OLD' electronics. where most repairmen these days seem to just want to replace complete boards/systems..

I was asked to look into fixing a Ultrasonic welder.. the guy's already spent R30 000+ ($2500) on it, and when it still did not work, the repair guy said get a new one.. Main problem appears to be that the TB5 2500 tube is not resonating at the right frequency...

I've searched around on Google and cant seem to find any schematics for the tube that match this purpose. (well actually i cant find any for this tube.) Information i do have is that the air wound coils on the tube are out of wack and need to be 'Tuned' for the correct frequency..

ANY help on this would be good.. Don't fancy doing it by trial and error, the tube is R15 00 ($1200) alone...

Thanks guys..

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Sch3mat1c
Posted: January 05, 2018 10:39 pm
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Radyne huh, must be ancient, back when they were Radyne Ltd.

Anyway, it's going to be a class C self-excited oscillator. If it's not oscillating, then clearly it's not getting enough gain at the desired frequency. There could be shorted or broken caps, coils or resistors. Are the plate and grid voltages within spec? I mean, okay, it's not going to have any grid bias if it's not oscillating (or if there's a C- supply, then it's not developing the extra bias that's normal), but...yeah.

Obviously, don't go probing around in there yourself, with it on. That plate transformer is probably 5000V or so. smile.gif

I wonder if you can find a ham radio enthusiast nearby who might have more experience with that kind of circuit?

Tim


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gremlinsa
Posted: January 06, 2018 03:16 pm
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QUOTE (Sch3mat1c @ January 05, 2018 11:39 pm)
Radyne huh, must be ancient, back when they were Radyne Ltd.

Anyway, it's going to be a class C self-excited oscillator. If it's not oscillating, then clearly it's not getting enough gain at the desired frequency. There could be shorted or broken caps, coils or resistors. Are the plate and grid voltages within spec? I mean, okay, it's not going to have any grid bias if it's not oscillating (or if there's a C- supply, then it's not developing the extra bias that's normal), but...yeah.

Obviously, don't go probing around in there yourself, with it on. That plate transformer is probably 5000V or so. smile.gif

I wonder if you can find a ham radio enthusiast nearby who might have more experience with that kind of circuit?

Tim

Thanks Tim..

Apparently it was working fine for a long time.. THEN.. they moved it across the workshop (and down some stairs) and then it stopped working..

So next time i go past i think i'm going to start looking for loose, damaged, broken bits around and behind things..

I'm also a little suspect on the looooooooooooooong bridge of diodes on the left. (maybe one there broke loose..

Still would like to find a schem of some sort to help...


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damien
Posted: January 06, 2018 11:35 pm
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Is it worth contacting Radyne and seeing if they have anything in the archives?

http://radyne.com/

Never, someone there might be willing to help. wink.gif

Damien


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