Applying vector lessons to life

That last message was supposed to be private (though if anyone can help it
will be much appreciated). However, I did learn some things today that
should help everyone, or at least the married people. :-)

If you can tell your wife that you are saving at least $150, because fixing
games has taught you how to fix the TV, you will likely be a popular fellow.
Even if you spouse doesn't give you a problem, you can put that money toward
that Wintron you've been saving for. :-)

I was surprsed when I opened the TV that it looks more like the Vector
monitors I've worked on than the Raster ones. I'm working without a
schematic but it's sparse in there. Seems most of the work is done by an
IC, then you have deflection amps, three colors amps, and a power supply.
Sound familiar ? If you've worked on a few vector monitors and are
confortable testing for bad parts, working on a modern TV isn't impossible.

Most importantly, remember the lesson of the BU406D no matter what you work
on. I was staring at every spec of that NTE cross, thinking "I can't
POSSIBLY need 10 amps in to the color gun! I was about to put a slightly
smaller standard trans when I noticed the line "Intgrated base-emitter
resistors" in the description. That was CLOSE !

I've jury-rigged a standard trans with external resistor/diode. It works,
but has some artifacts, so I'ld stil like to find the right part. If this
sheds any light on the BU406D situation: I measured the resistance on a
good on at 470 ohms, so I put a 470 ohm resistor across the base and
emitter.

It worked, but on black screens there were red lines down the screen. (This
trans is the red driver on the neck board). Not mentioned in the
description, but in the schematic of the NTE part, was a diode across the
collector and emitter. I added a 1N-4002, and the lines are better, but
not gone. I'm guessing either there is external interferance being picked
up, or the diode isn't fast enough.

People have mentioned adding external diodes to a BU406, has anyone done
this, and did you use a resistor too ? I measured the B-E resistance on a
BU406D and came up with something around 50 ohms.

-Chris

==========================================================
Chris Candreva -- chris@westnet.com -- (914) 967-7816
WestNet Internet Services of Westchester
http://www.westnet.com/

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Received on Thu Jan 3 18:53:50 2002