an elementary question about lamps

[Leo Tick]

On a halogen lamp the dimmer assembly was it seems
to me a lot of electronics -3 diode and a transistor.
What's this stuff all about. Naturally it's gone
south (else why else would I be here). I'd love
a complete replacement but there are phyical restraints.
So 1. Where might I be likely to find a replacement.
2. If failure on 1., it is the trnsistor that is gone
(took a trace but that is a non-problem). The
stuff on the transistor is:
600F
BT138F
PHm42
Any info/help would be most appreciated---Thanks

 

[Josey]

On a halogen lamp the dimmer assembly was it seems
to me a lot of electronics -3 diode and a transistor.
What's this stuff all about. Naturally it's gone
south (else why else would I be here). I'd love
a complete replacement but there are phyical restraints.
So 1. Where might I be likely to find a replacement.
2. If failure on 1., it is the trnsistor that is gone
(took a trace but that is a non-problem). The
stuff on the transistor is:
600F
BT138F
PHm42
Any info/help would be most appreciated---Thanks

Try http://tinyurl.com/iwks

Jc

 

[Dave D]

On a halogen lamp the dimmer assembly was it seems
to me a lot of electronics -3 diode and a transistor.
What's this stuff all about. Naturally it's gone
south (else why else would I be here). I'd love
a complete replacement but there are phyical restraints.
So 1. Where might I be likely to find a replacement.
2. If failure on 1., it is the trnsistor that is gone
(took a trace but that is a non-problem). The
stuff on the transistor is:
600F
BT138F
PHm42

That's not a transistor, it's a triac. (basically an AC thyristor) The
relevent numbers are BT138F and 600F, the latter being the max voltage. I'm
not sure why you think 4 components is a lot, that's actually a very simple
dimmer.

What exactly is wrong with it? The usual components to fail on dimmers are
the triac and the potentiometer. Triacs usually fail short circuit, (the
light will stay on all the time) and pots fail open or intermittant. The
latter is a simple check with a multimeter.

Unless all 3 of the remaining devices are clearly diodes, one of them is
likely to be a diac, which aren't simple to check.

Dave

 

[Bennett J. Price, Ph.D.]

Perhaps this is what you're looking for:

http://www.pointshop.com/Mall/Catalog/Product/ASP/product-id/296209/store-id/1000018611.html

 

[Leo Tick]

I want to thank everyone for taking the time to respond.
It's been a long time since I did any electronics
repair--PDP11 was the last.
As tt whether it mailed open or claset I could say opeb
but that would be misleading since a trace from the triac melted
so In my ignorance I would say the triac shorted.
If I could find a replacement I would prefer that but
the physical constraints are great. It is an expensive
lamp fixture so I have no problem replacing any and all
components and repairing the trace.
The marks on the circuit board are the usual diode symbol
two have a black with the usual diode markings
and the third is the "glassy" kind. Ther is also
ine resistor an a cap.
I'll try the URL's suggesteed and if tis fails
I'll replace the trac. For the moment I only
have a digi-key catalog which shows
logic triacs and gated ones and alteernistor triacs
The numers dont match but this may be a japanese
kind of numbers. The thing was made in tiwan,
thanks again