On Fri, 25 Sep 2009 10:49:59 +0000 (UTC),
(Andrew Gabriel) wrote:

In article ,
robgraham writes:
I got two of these (why didn't I get a spare ?) out of a skip some
years back (~2000).

One of them works fine but the other is an unwilling starter - switch
on/flash/switch off/ wait for a count of 8/repeat about 6 times for
light to start.

I tried changing the tubes around - no change. I put the bad one up
in the new workshop when it was initially wind and water tight, and
decided yesterday that it was time to change them over. I came to the
conclusion it was easier to change the modules rather than the whole
light, and the fault follows the modules.

I've got a basic concept of how these things work ( I am an
electronics engineer), but does anyone know what the starting
circuitry is likely to be like so that I can try and trace down the
faulty component? The electronics is all discrete components

On some, & only some, it's a winding of a couple of turns per filament
on the HF output transformer. All the power goes to the filaments
until the tube strikes.


Not going to be able to advise on repair over usenet, except
a common problem with ballasts of that age is arcing between
PCB traces, which is caused by poor washing of the PCB during
manufacture resulting in eventual breakdown, combined with
the manufacturers being new to designing PCB's carrying 600V
pulses and laying the tracks too close together. You might be
able to fix by peeling off an affected track and replacing
with a soldered insulated wire. Other than that, if there's
no obvious damage, you'll have to fire it up with the PCB on
a electronics workbench and try to spot arcing on the board
or inside any components. Needless to say, these have
dangerous voltages inside (significantly worse than mains),
and may remain dangerous a long time after switch-off.

However, I suggest you get a new electronic ballast. Basic
single tube non-dimmable are usually under £10 on eBay.

Or 7 or 8 quid for the Phillips "HF-matchbox"series at RS.

Derek