Replaced flashtube on Novatron--not working

[BetterSense]

I bought a Novatron flash unit with 3 heads, one of which had a broken tube. I bought a new tube on ebay, and replaced the old one...seems pretty hard to install it wrong; there were only 3 connections and I just soldered them where the old one went. However it doesn't work.

The other 2 flash heads work. So either I got a bad tube, or the flash head internals were bad in addition to the flash tube being broken. I could take the new flash tube and try it on one of the other two working heads just to test it, but I was wondering if there is a break-in procedure you have to do to new flash tubes, or if it's possible that this new flash tube's breakdown voltage is higher than the other two, well-used flash tubes, and if so, if there's anything I can do to get it working.

 

[removed account4]

it might be worth your while
to contact novatron.
they are in tx and
answer the phone / emails ...

 

[Konical]

Good Morning, BetterSense,

I agree with contacting Novatron. Years ago, I had to replace a broken flash tube. I ordered directly from Novatron and received the tube very quickly. As I recall, installation was very simple.

Konical

 

[greybeard]

It seems possible that someone powered up the flash with a broken tube, and the trigger transformer was fried because the trigger electrode was in contact with the high voltage end of the tube. If this isn't perfectly clear, then for safety's sake you should probably contact Novatron, or even farm the repair out to a competent shop.

On the other hand, if you are qualified to work on potentially lethal electronics, and have the right tools, you could measure the secondary resistances of the trigger transformers in working and non-working heads and see if the bad one is either open or shorted. I would expect something on the order of hundreds to a thousand or so ohms; open or shorted probably means that it is bad. Bear in mind that some flash tubes are series triggered, in which case the transformer would be in the power pack instead of the head. Naturally, as a first step you would check for continuity of the cabling and connectors, and presence of high voltage in the head (this is where the safety issues really get serious! Proceed at your own risk....)

 

[BetterSense]

The other two flash heads work fine when plugged into any of the ports on the power pack, so the problem must be in the head or the cable. I never would have thought to check the transformer in the head; to be honest although I'm pretty knowledgeable about electronics I'm not knowledgeable about flashes in particular.

 

[epatsellis]

fwiw, novatron heads do in fact have the trigger transformers in the heads.