Re: K6100 T901

From: <akswanson_at_ntelos.net>
Date: Sun Aug 28 2011 - 22:27:27 EDT

        Sorry, I have confused..I need the little transformer that drives the
BU207. My flyback is ok.

         

> You can get one here:

>

> http://www.cinelabs.com/wg6100/

>

> which has link to here:

>

> http://arcadeshop.com/wgxy-fb/wgxy-fb.htm

>

> $79, and comes with extra protection components and a new focus
assembly.

>

> Note, I&#39;ve never ordered or used one of these flybacks, I just
remmeber

> seeing it recently while searching for other parts to bring a 6100
back

> to life.

>

> ___

> Ken

>

>

> akswanson@ntelos.net wrote:

>> I had suspected the triple nickel (555), and indeed it was
fried. It

>> also took out Q905, AND T901.. I verified this by trying T901 in
a

>> known good HV unit. I got smoke, and another blown Q905.. So
if

>> anybody knows where I can get a replacement T901 thatd be
swell!

>>

>>

>>

>> > I&#39;m not saying that you don&#39;t have a bad T901, but
can you verify

>> that

>> > IC901 (555 timer as a simple oscillator) is running. A
scope would

>> show a

>> > nice square wave coming out at pin 3. If it is stuck in the
high

>> state,

>> > it would keep Q904 and Q905 turned on constantly and that
would

>> certainly

>> > cause your problem. Of course in this state, there would be
no HV

>> output

>> > at all. Check ZD900 for 13V across it. ZD900 is the voltage
regulator

>> > for the 555 chip. If the zener is partially shorted and
there isn&#39;t

>> > enough voltage across the 555 chip, then the 555 chip
output might be

>> > stuck even if there&#39;s nothing wrong with it. If the
zener is

>> > open-circuit, the 555 chip will likely have blown.

>> >

>> > You should remove R917 and leave it out until you can
verify that

>> IC901 is

>> > running okay and that the transistors Q904/905 are both
switching. To

>> > functionally test Q905, you can add a temporary 10k (to
47k) resistor

>> > (1/2W to 1W) from +Vsupply (+28V) to Q905 collector. If
scope shows a

>> > good square wave, remove the temporary resistor and return
your focus

>> to

>> > T901.

>> > If you do not have a scope but you have a voltmeter,
connect your

>> meter

>> > (-) to ZD900 anode or IC901 pin 1. Use the meter(+) to
measure

>> voltage at

>> > ZD900 cathode and IC901 pin 8. Both should be about 13V.
Measure

>> IC901

>> > pin 3. If it is running, it should be around 6.5V
plus/minus around

>> 0.5V

>> > roughly. The point here is that pin 3 should be outputting
a square

>> wave

>> > having roughly a 50% duty cycle so the voltmeter should
show

>> approximately

>> > one half the chip supply voltage.

>> >

>> >

>> > William Boucher

>> > http://www.biltronix.com

>> > ----- Original Message -----

>> >

>>

        From: akswanson@ntelos.net

>> > To: vectorlist@vectorlist.org

>> > Sent: Sunday, August 28, 2011 9:20 AM

>> > Subject: VECTOR: K6100 T901

>> >

>> >

>> > One of my 6100s had a fire on the HV board, took out R917
and Q905. I

>> > replaced those, and got smoke again.. Comparing the
resistance of the

>> > primary of T901 to a known working T901 I get 9.5 Ohms on
the

>> suspected

>> > bad one and 17 ohms on the known good one. I get the
feeling I melted

>> > the varnish on the wiring and shorted them together.. Does
anyone

>> know

>> > where (or have) and extra T901? Also, Is there a secondary
cause,

>> such

>> > as a flyback failure that would cause this kind of failure?
I dont

>> > want to blow the dang thing again..

>> >

>> >

>> >

>> > Andrew

>> >

>>

>
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Received on Sun Aug 28 22:27:30 2011

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