"Rene" schreef in bericht
...
"Inty" schreef in bericht
...

"Rene" ha scritto nel messaggio
...

store gave me a BU1508DX instead of a BU1506DX which was not in stock
(but
SPPPPPPRRRRRRRRRRRRRRRR!!!!T
There's something that isn't ugual on those two xistors... they aren't
interchangable, BU1508DX has VCESAT of 1.0V and BU1506DX has VCESAT of
5.0V
and there are some diverse parameters...

Dear Inky,

Very funny, in another store they also said that their computer proposed
the 1508 as a 1:1 replacement. I do not trust their computers. Well, I
mean, I do not trust the people who put this info into their computers.
I ordered a new LOPT and also two 1506's. When I have results, I will post
them here.

Thank You very much for replying!

Sincerely,
Rene



Comparing the datasheets of both types reveals they virtually be the same
although the 1508s specs are slightly better. The VCESAT Inky mentioned is a
maximum so worst case. The actual VCESAT may be below 1V for both types.

The LOPT is a pretty expensive device. You can find many tips for checking
the it at:
http://repairfaq.ece.drexel.edu/sam/flytest.htm
a relatively easy to build tool at:
http://members.ozemail.com.au/~bobpar/fbt.htm

Although the LOPT might be defective, the control signal of the HOT is at
least as suspective. You hardly can check this out without an oscilloscope.
You need to check the frequency and the pulsewidth. The pulsehight may give
you an idea whether or not the pulse has enough power to drive the HOT
correctly. A positive DC level (p. e. caused by a leaky driver transformer)
will be disastrous for the HOT. For maximum certainty you'll need the specs
of the manufacturer.

petrus bitbyter