On Sun, 17 Apr 2005 01:04:47 GMT, "James Sweet"
wrote:

wrote in message
...
On Sat, 16 Apr 2005 19:25:29 -0400, "Art"
wrote:
Scope probe set near the ballast wil produce a high freq display if the
ballast is running.
Thanks Art - Googling around tonight brings up a similar tip - holding
a small discharge tube near the inverter board apparently causes it to
light up if board is working

Also have gleaned that these inverters tend to have an internal trip
such that if an HT feed circuit to *one* backlight goes down, it trips
a cutout & all the others are disabled on the board.

Guess it all points towards the inverter board - this particular one
is a "Hitachi invc551" - comes up on Google $99 - cheaper options?
(UK)?

There seems to be mention of (SMC?) fuses in inverter boards that can
blow - I would be glad of a pointer to a quick fix - tho I can't
immediatly see any of these on this board..

-----

Supplimentary question: there seems to be a small web industry
building up around the unreliability of these HT boards - what are the
issues that seemingly make them sooo fragile??



They're just cheap, that's the main reason they fail.

Lots of surplus boards out there though not all will support dimming if you
need that.



Yeah yeah - also 1600V+ floatin arond - spookey things might happen -
PCB track capacance etc etc - beyond my knowledge (& capacity!)...

---

my dear old Dad used to say to me -

"Never trust an electrician with no eyebrows".

;-)