Re: K6100 T901

From: <akswanson_at_ntelos.net>
Date: Wed Sep 07 2011 - 09:47:23 EDT

        Send me your address and I&#39;ll mail you the wire.

         

> Excellent! Thanks! Do you happen to have a micrometer or calipers
to

> measure

> the diameter of the wire? If you do, please use sandpaper to take
off the

> lacquer coating to get an accurate measurement. Or you can stuff
both

> wires

> in an envelope and send it to me. :-) I have a micrometer and
calipers.

>

> Let me know if I should send you my address.

>

> So, looking at the schemtics, T901 is switched on and off between
the B+

> and

> B- rails, for about 53 volts minus the drop across Q905, so
let&#39;s call it

> 52

> volts. Then the secondary is listed as being -27.6, but it&#39;s
connected on

> one side to B-, or -26.4 volts. So, that&#39;s 1.2 volts across the
secondary

> and R926. I&#39;m not sure why R926 is a 2W resistor, because the
only

> current

> would be to drive the base of a transistor, which should be in the
mA

> range.

> Then again, the size of the secondary wire in the picture is thicker
than

> that required to drive tens of mA.

>

> Let&#39;s say it&#39;s 100 mA, then the drop across R926 is 0.22
volts.

> So the primary is 26.4 volts versus the secondary at 1.2-.22 is
0.98,

> or a ratio of 26.9:1. And 625 turns / 23 turns is a ratio of
27.2:1.

> So your count of the turns ratio seems rather accurate.

>

> In other words, I have faith in your counted turns. :-)

>

> ___

> Ken

>

>

> On 09/04/11 07:27, akswanson@ntelos.net wrote:

>> Ok.. I pulled my transformer

>>

>> Primary : 625 turns (give or take some..lol Id say its within a
percent

>> or two)

>> very fine wire

>>

>> Secondary: 23 turns

>>

>> pics for your enjoyment:

>>

>>
http://www.flickr.com/photos/mcandrewsnd/sets/72157627466514605/

>>

>> > I heartily agree that whoever takes the time to investigate
the

>> properties

>> > of the T901 transformer should post the info the the list,
and

>> hopefully

>> > the list owner will save that info on the vectorlist
website

>> archives.

>> >

>> > If I finish rebuilding my living room/stero/TV setup this
weekend,

>> I&#39;ll

>> > pull the working T901 from my spare WG high voltage board
and try to

>> > measure the turns ratio and the resistance of both coils.
I&#39;ll post

>> the

>> > info here when I get it.

>> >

>> > ___

>> > Ken

>> >

>> >

>> > On 09/02/11 18:11, litterbox99@mchsi.com wrote:

>> >> I can&#39;t imagine that someone hasn&#39;t done
this

>> >> before and documented it...

>> >>

>> >> It would be very usefull information.

>> >> Kudos ! To someone who gives it a try.

>> >>

>> >> Todd

>> >>

>> >>

>> >>

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

>> >>

>>

        From: "Ken Sumrall"<k_lists@scrapheap.net>

>> >> To: vectorlist@vectorlist.org

>> >> Sent: Friday, September 2, 2011 6:53:26 PM GMT -06:00
Central

>> America

>> >> Subject: Re: VECTOR: K6100 T901

>> >>

>> >> If the old transformer is not too burned up, you can
count turns as

>> you

>> >> unwind

>> >> it. Sometimes only the insulation melts, leading to
shorted bad

>> >> transformers,

>> >> but easy to count the turns as you unwind it.

>> >>

>> >> However, other times the wire itself melts/breaks, and
then its

>> harder

>> >> to

>> >> count as you unwind. If only one of the two coils is
broken, you can

>> >> use

>> >> the turn count from one coil, and the measured ratio
from a working

>> >> transformer

>> >> to figure out the turns count for the broken coil.

>> >>

>> >> Good luck if you choose to do it, and if you don&#39;t
want to, you can

>> send

>> >> me

>> >> your burned out transformer and I&#39;ll give it a
try.

>> >>

>> >> ___

>> >> Ken

>> >>

>> >>

>> >> On 09/02/11 17:40, akswanson@ntelos.net wrote:

>> >>> I have been contemplating rewinding it. I&#39;ll
pull it apart and see

>> how

>> >>> bad. I

>> >>> Love the 250ma fuse mod. Im thinking of some kind
of fuse mod for

>> this

>> >>> G08 im

>> >>> working on that keeps blowing output transistors
(yes they are the

>> >>> correct

>> >>> devices, not the 3716s). Ugh.

>> >>>

>> >>> > I&#39;ve thought about this some more, and it
seems to me this would

>> >>> not

>> >>> > be that hard to rewind yourself. You can
easily measure the turns

>> >>> ratio

>> >>> > of a working transformer with a signal
generator set to the right

>> >>> > frequency

>> >>> > and a volt meter to read the output. Or just
probe the input and

>> >>> output

>> >>> > terminals of the transformer in a working
circuit, though the

>> load

>> >>> on the

>> >>> > transformer could affect the readings.

>> >>> >

>> >>> > Then you could estimate the number of turns on
the primary by

>> >>> measuring

>> >>> > the

>> >>> > resistance of the wire and it&#39;s gauge, and
using a chart that

>> >>> lists the

>> >>> > resistance/foot of the standard wire
gauges.

>> >>> >

>> >>> > Winding transformers is not fun, but not hard
to do. Just time

>> >>> consuming.

>> >>> > If there is enough demand, it might be worth
while to get a batch

>> >>> of them

>> >>> > custom made.

>> >>> >

>> >>> > I know someone who sold a Scope Clock kit, and
he had the special

>> >>> > transformer

>> >>> > he needed for his design custom made. I could
ask him where he

>> got

>> >>> them

>> >>> > made

>> >>> > if there is enough interest to investigate
this further.

>> >>> >

>> >>> > Is there a pent up demand for this
transformer?

>> >>> >

>> >>> > ___

>> >>> > Ken

>> >>> >

>> >>> >> --- 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&#39;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&#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

>> >>> >>> >>> >

>> >>> >>> >>>

>> >>> >>> >>

>> >>> >>>

>> >>> >>
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>> >>> >>> >> ** Please direct other
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>> >>> >>> >> chris@westnet.com

>> >>> >>> >>

>> >>> >>> >>

>> >>> >>> >

>> >>> >>>

>> >>> >>
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>> >>> >>> > chris@westnet.com

>> >>> >>> >

>> >>> >>>

>> >>> >>
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Received on Wed Sep 7 09:47:26 2011

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