Re: K6100 T901

From: <akswanson_at_ntelos.net>
Date: Sun Aug 28 2011 - 22:28:26 EDT

        lol..no worries.. I guessed maybe I had the wrong part ##.  I will
DEFINATLEY check that out!!

         

> Oops, I just realized you&#39;re not talking about the flyback, but
the

> smaller transformer on the HV board.

>

> Sorry, I don&#39;t know where to get a new one of those. However, I
do

> recommend you read the installation manual for the replacement
flyback

> which you can find at the first link below. It includes instructions
on

> how to add 3 fuses to the HV circuit to protect components
(including

> T901) in the event of another failure like the one you have.

>

> ___

> Ken

>

>

> Ken Sumrall wrote:

>

>> 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

>>> >

>>>

>>
---------------------------------------------------------------------------

>> ** Unsubscribe, subscribe, or view the archives at

>> http://www.vectorlist.org

>> ** Please direct other questions, comments, or problems to

>> chris@westnet.com

>>

>>

>
---------------------------------------------------------------------------

> ** Unsubscribe, subscribe, or view the archives at

> http://www.vectorlist.org

> ** Please direct other questions, comments, or problems to

> chris@westnet.com

>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Sun Aug 28 22:28:28 2011

This archive was generated by hypermail 2.1.8 : Sun Aug 28 2011 - 22:50:01 EDT