"Kevin McMurtrie" wrote in message
...
In article ,
"ian field" wrote:

"Oppie" wrote in message
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"ian field" wrote in message
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The circuit is straightforward enough but the diode devices are house
coded.

Before putting it all back together I tested each type of diode with
my
DMM diode check, the bridge diodes have a Vf of .538V - consistent
with
standard recovery types, the one I've marked as '5' had a Vf of
1.553 -
divided by 2 that's just over .7V - consistent with what my DMM tels
me
for a zener junction, but I'm guessing 3 standard junctions.

The one I've marked as '6' is the critical one, as it looks like an
ordinary diode I'd guess maybe something from the P6K range.

The thyristor is no great mystery - its a TN22-1500 Startlight from
ST:

http://www.datasheetcatalog.org/data...tronics/mXyzxr
r.pdf


ST used to have an IC that was for starting magnetic ballast
fluorescents.
guess it went obsolete when CFLs became more mainstream.


It all started when the landlords electrician insisted on fitting an iron
ballast 2D luminare in the bathroom - despite my protests that I have
plenty
of 18W CFLs in the cupboard that only use 2/3 of the electricity and
don't
cost a fortune to replace the tube (which will also wear out quicker than
a
CFL).

The 2D was a POS from day 1 - it always flickered for a few (long - when
I'm
bursting for a **** and can't see to take aim) seconds, and when it did
eventually start it took nearly an hour to warm up enough to stop
shimmering.

Over time its started taking so long to strike that when I want to go to
the
bog, I have to switch the light on then go have a cuppa while I wait for
the
light to come on!

I've ordered a new tube on ebay but while I wait for it I decided to nip
down the DIY store and get a new starter to try - then I noticed they had
electronic one's.

With the dodgy tube, the electronic starter makes the heaters glow for
about
a second or two, then the tube just strikes without any flickering.

Though there is a growing temptation to graft the PCB from a CFL into the
4
pin 2D fitting.

Back when I rented, I often replaced the magnetic ballasts with
electronic ones. The simple and cheap upgrade made the lamps brighter,
eliminated flicker, and the bulbs lasted longer than my stay.

I HATE CFLs. The quality is crap no matter what the bulb costs or whose
brand is on it. Half of them die within 2 months and those that remain
rarely last for a year.


I think I'm down to the last cheap & nasty Morrisons own brand (£1.99 - back
when the name brands were still charging over £5), the last one I had to
change was pretty dirty for having been there so long, the Philips in the
kitchen is a bit more recent (just over a year) but it does run 24/7.

But maybe I should look into a purpose made electronic ballast.