I fixed one of these with the exact same fault several weeks ago - you
have one or more blown picofuses on the inverter board - IIRC there are
four of them F2 F3 F4 and F5 - use a ohm meter to find and replace the
open ones. I suspect that they are slightly under rated at 1.25A, and open
pretty easily. I replaced 2 of them with 1.5A devices and it's worked fine
ever since.


Thankyou so much.
I'd looked around inside but I would never have spotted those *tiny* fuses.
I tested one of the boards, and two were indeed o/c. Even my weller station
is not good enough to replace them, but in true Heath Robinson fashion I
extended the connections out with wire to two normal glass 1.6A fast fuses.
That display seems OK now, it ran for 20 minutes with no problem. Would you
say it was a new lease of life or short term? Is it the ageing of the tubes
that causes the failure?
I'll get round to checking the other two displays soon, but once again,
thankyou for your help.