Vectorlist Archives: Re: K6100 T901

From: <akswanson_at_ntelos.net>
Date: Tue Sep 20 2011 - 19:20:08 EDT

It looks like from the schematic that the same transfomer is on the
Mototola XM chassis. The circuit is identical to the WG V100X and
the 6100. The impedances (or resistances more likely) even match up
to what I measured on the xfomer. I have a scrap XM701 I think
around here somewhere..Im gonna try it before I butcher a (pricey) WG
v1001 chassis..

> akswanson sent me pieces of the wire from the primary and secondary
coils

> of

> T901. Using some very fine sandpaper, I sanded off the insulation,
and

> measured

> the wire diameter with some nice Mitutoyo calipers.

> The primary wire measured .0065 inch, which according to
wikipedia:

> http://en.wikipedia.org/wiki/American_wire_gauge

> is AWG 34.

> The secondary wire measured at .025 inch, which is AWG 22.

> So, putting it all together, the specs for T901 are:

> Primary coil: 625 turns of AWG 34 wire

> Secondary coil: 23 turns of AWG 22 wire

> Anyone want to try and wind their own? akswanson has an empty bobbin
and

> core. :-)

> ___

> Ken

> On 09/06/11 18:38, Ken Sumrall wrote:

>> 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's call

>> it 52

>> volts. Then the secondary is listed as being -27.6, but it's
connected

>> on

>> one side to B-, or -26.4 volts. So, that's 1.2 volts across
the

>> secondary

>> and R926. I'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's say it'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'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'll post

>>> the

>>> > info here when I get it.

>>> >

>>> > ___

>>> > Ken

>>> >

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

>>> >> I can't imagine that someone hasn'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't want to, you can

>>> send

>>> >> me

>>> >> your burned out transformer and I'll give it a
try.

>>> >>

>>> >> ___

>>> >> Ken

>>> >>

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

>>> >>> I have been contemplating rewinding it.
I'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'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'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'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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>>> >>> >>> >> chris@westnet.com

>>> >>> >>> >>

>>> >>> >>> >

>>> >>> >>>

>>> >>> >>

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Received on Tue Sep 20 19:20:11 2011

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