THREAD HIJACK: Re: K6100 T901

Sorry guys, but . . . . speaking of Hans O - where's he been? Haven't seen anything of him for a while.

--- k_lists@scrapheap.net wrote:

From: Ken Sumrall <k_lists@scrapheap.net>
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: K6100 T901
Date: Sun, 28 Aug 2011 19:33:27 -0700

I searched my local archives of the vector list, and found this post
from July 8, 2007 from Hans O:

> AH, now I remember. They're found in old B & W raster chassis.
> Track down an old 19V1001 or 1003 chassis. Should be a bunch of
> dead ones out there.
>
> Hans O

Good luck!

___
Ken

akswanson@ntelos.net wrote:

> lol..no worries.. I guessed maybe I had the wrong part ##. I will
> DEFINATLEY check that out!!
>
>
>
> > Oops, I just realized you're not talking about the flyback, but the
> > smaller transformer on the HV board.
> >
> > Sorry, I don'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'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'm not saying that you don'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't
> >>> > enough voltage across the 555 chip, then the 555 chip output might
> >>> be
> >>> > stuck even if there'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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> >> http://www.vectorlist.org
> >> ** Please direct other questions, comments, or problems to
> >> chris@westnet.com
> >>
> >>
> >
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> > chris@westnet.com
> >
>
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Received on Sun Aug 28 22:49:20 2011