Preventative maintenance on a Synrad 48-2? Or let it die then fix?

[Andrew Stow]

Been reading about people having problems with capacitors on the RF board of these olders tubes.

The system is old enough that such an event may well be around the corner. This is on a legend 32 from around 2000.

My question is:

Should I be proactive and replace the common fail components then retune before that happens (I haven't the first clue how to go about retuning) OR should I simply go about my merry way and use it until it fails and then replace components and retune as necessary?

Is there a downside to waiting for it to fail?

[Dave Sheldrake]

I guess you likely have a car Andy? would you replace the engine (or parts of it ) if you thought it may one day fail? Fixing something that isn't currently broken can on occasion be a good way to have something broken that needs fixing :)

There is of course the consideration that it may go pop when you most need it but having the parts on hand (as they cost very little) would likely solve that problem if/when the need arises.

just my opinion of course :)

cheers

Dave

[Andrew Stow]

Yeah, "If it ain't broke, don't fix it!" was one thing I considered.

But what I'm wondering is if there's something else that can get fried in the process of one or more of these capacitors failing?


I put spin-on oil filter adapters on my old deuce and a half army truck multifuel... so in answer to your question: "Maybe..." ;)

[Dave Sheldrake]

But what I'm wondering is if there's something else that can get fried in the process of one or more of these capacitors failing?

Possibly but very unlikely, it's more likely to be damaged by replacing parts and making a mistake or slipping than from a cascading fault. In the event of the resonator failing there are other things that could go wrong so I wouldn't advocate fixing anything until it needs it or you may end up fixing something that doesn't fail and missing something that does. Improving something is one thing, replacing on a like for like is a bit different :)

cheers

Dave

[AL Ursich]

Being an electronic guy my take is that it could push the future problem further up the line like posted above. In my opinion the best prevention is heat control... prevent the inner workings from having to deal with excess heat... The cooler it runs the longer it will last...

AL

[Dan Hintz]

I'm with Dave on this... don't touch it until something is obviously wrong with it. Caps are the common weak link in the RF section, but when they fail the worst that will typically happen is the RF section can no longer resonate, so no output (and no lasing)... no other components break.

[Rodne Gold]

Photovac told me that my "repairs" on my J48 makes it more difficult for them to fix..leave it be....

[Chuck Stone]

I would get a few caps and keep them on hand, anyway.
Worst case, the tube doesn't fail and you're out $5
If you've dropped power recently, it could be a cap..
better to have it on hand than to be down waiting for
a shipment.

[Andrew Stow]

Thanks, that's what I'll do.

Does anyone happen to know which caps are most likely to blow and what their values are for these? I'd like to avoid taking it apart until there's an actual problem.

Mine is specifically a J48-2s-Epi. Which I take to mean it's a J revision 48-2, air-cooled, made for Epilog, right?