[TechAssist] Re: Sony IK problem bypass

  • From: Jorge Camboni <geo@xxxxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Wed, 08 Sep 2004 20:26:51 -0500

I am sending to you directly the same message I sent 3 times to=
 techassist...
just adding these lines, nothing else changes.. maybe the techassist system=
 is
configured for 7bits ascii text (sounds weird) or something like that. I am
pretty sure there is no html in these messages. Just analyze it.-


Well, you were faced to a plain spanish text, that=B4s all... and it has=20
nothing to do with Utah or
whatever. Just a correctly written technical article in spanish. (here in=20
Texas, for instance,
spanish is WIDELY spoken)

I got an approximate traslation by feeding chunks of text into the Alta=20
Vista online translator.
Besides some paragraph sounding kinda funny, the traslation seems to be=20
fairly easy to
understand



The IK circuit  in the  Sony television sets of recent generations (1990=20
on), on circuits controlled by microprocessor, count among other things=20
with a denominated circuit IK (current of cathode), that is in charge to=20
monitor the current of the cathodes of the TRC (Cathode ray tube, or=20
Cinescopio). The microprocessor in combination with the circuit "jungla"=20
(chrome-video), and a series of transistors (and other components) in the=20
circuits corresponding to the three cathodes, are the ones in charge to=20
make that task. Operation of circuit IK. From each one of the video outputs=
=20
(R, G, B) of the jungle IC three pulses are sent, one to each circuit of=20
exit of video. These pulses are in fact three scouting lines or horizontal=
=20
sweeping, each one of which is sent to the respective circuit of cathode so=
=20
that this it activates during the exploration of a line.

These lines are not visible in the screen, since they are sent during the=20
beginning of vertical sweep, in the area of "blanking", but they can be=20
seen in the superior part of the screen if the vertical height (VSIZ) in=20
the Menu is reduced slightly on watch. This circuit, besides to verify the=
=20
correct operation of the TRC, allows to make automatic tunings, within the=
=20
IC jungle, to compensate the small differences of emission between the=20
cathodes and to maintain therefore the correct color of the image. The=20
current of the cathodes is detected by 3 circuits put in between the=20
exciting amplifiers and each one of the cathodes. These circuits, send a=20
signal, proportional to the current of each one of the cathodes, to a=20
circuit Buffer, from where they are sent to the circuit jungle.

In many equipment these circuits are conformed by discrete components=20
(transistors, diodes, resistance, etc.) but in more recent models, all the=
=20
exciting stage of the TRC (exits of video or TRC drive) and the components=
=20
of circuit IK they are included in a single IC like the TDA6108, for=20
example. Almost from the moment at which the equipment is ignited, the=20
jungle IC  sends the respective pulses to each one of the video out=20
circuits, while it maintains video blanking or mute (black screen). As the=
=20
cathodes reach the temperature necessary to emit electrons, the current of=
=20
such, generates in the respective circuits detectors, a pulse similar to=20
the applied one and whose amplitude is proportional to the current of the=20
cathode. To see image. When the pulses in circuit IK reach certain=20
amplitude, video blanking is deactivated and the image appears in screen.

The lack of video (black screen), in these TV Sony, sometimes usually=20
causes confusion among the technicians, because when not having exits of=20
signal of the IC jungle, tend to suppose that the problem is in the same=20
one, as usually it is the case in television sets with more conventional=20
circuits. When we faced the repair of a TV Sony of recent generations (1990=
=20
on), that presents/displays absence of Video (black screen), permanent or=20
intermittent and with normal sound, we must make the following steps: To=20
increase the polarization of G2 by means of potenciometro of SCREEN. If the=
=20
screen is illuminated with "raster" (sweeping) normal, we can discard the=20
possible problems in the circuits of sweeping. (a defect in the circuit of=
=20
Vertical, podria to cause the same symptom) This also allows to verify in=20
fast form, if the necessary voltages for the operation of the TRC exist=20
(filament, anode, G2). To verify that the circuit jungle receives the=20
voltage of corresponding feeding. To verify that they arrive at the=20
integrated jungle you indicate them of "micro" (clock, dates). If all this=
=20
is correct, is very possible that the problem is in the exciting circuits=20
(exits of video), in the TRC, or own circuit IK. The following advisable=20
step, is to verify the state of the TRC. If the same one presents/displays=
=20
low emission in some of the cathodes, or if it has some short internal one=
=20
it can cause that circuit IK stays in "corte". For this he is advisable to=
=20
use a Probador of TRC. If it is not had one, the following verification can=
=20
be made: With the ignited TV to momentarily place a about 15 resistance of=
=20
or 20K 2W, between earth (ground) and each one of the cathodes (KR, kg and=
=20
KB), one simultaneously. When doing it the screen in intense form was=20
illuminated, with the corresponding color. The intensity must be similar=20
when doing the test in the three cathodes. If some of the colors does not=20
appear or it does in tenuous form, is exhausted or defective indication of=
=20
TRC. This is not a very precise test. Most advisable, as it were indicated=
=20
previously, it is to use a Probador of TRC, nevertheless, this test, aid to=
=20
determine if some of the tubes, is defective or with very low emission.

           How to deactivate or "cheat" the IK  circuit

In order to determine as it is the cause of a fault related to these=20
circuits, cheating the IK circuitry to deactivate the video blocking that=20
this it causes. This can be obtained, disconnecting originating line IK of=
=20
the plate of the TRC and placing three diodes of the type 1N4148 between=20
the pins of the integrated jungle, as it is in the figure. Of this form the=
=20
verification pulses, envoys from the IC jungle are introduced to this=20
again, with which it deactivates the video blockade, allowing to see the=20
image in screen. Of not appearing image when doing the suggested=20
modification, and having made the indicated verifications previously,=20
without to have detected anomalies, is possible that the jungle IC or some=
=20
associate component is  this defective. I hope that this helps to clear a=20
little, the doubts on the operation of this circuit, and to be able to=20
locate with more facility the cause of the faults that usually appear.


In diagram:

amplificador =3D amplifier
azul=3Dblue
verde=3Dgreen
rojo=3Dred

detector de corriente del catodo=3D cathode current detector

modificaci=F3n implementada para enga=F1ar al circuito IK=3D
=3D implemented mod to cheat IK circuit


I hope this text helps a little bit.

regards
Jorge


At 04:33 p.m. 07/09/2004 -0600, you wrote:
>All I did was send the info,....I never even tried to read it.
>I hope it is,.... what it says it is.
>Just do the resistor gigo,....and forget about the diaoides.
>;-)
>
>LLW
>
>LeRoy Westlund
>Westlund TV & Electronics
>97 North Main                                "Where there's a will,...
>Centerfield, UT 84622-0087           There's always a way."
>Ph./Fax  435-528-3822
>mailto:LLW@xxxxxxxxxx
>
>-----Original Message-----
>From: Doug Keller <dek@xxxxxxxxxxxxxx>
>To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx>
>Date: Tuesday, September 07, 2004 1:30 PM
>Subject: [TechAssist] Re: Sony IK problem bypass
>
>
> >Do you have an english translation? Some of us aren't from Utah and
> >speak spanish, or whatever that is.
> >
> >Doug Keller
> >Wis-Kel Electronics
> >101 Freeland Ave.
> >Terra Alta, WV
> >USA        26764
> >dek@xxxxxxxxxxxxxx
> >dek@xxxxxxxxxxxxxxx
> >http://www.tech-assist.org
> >"Learn from the mistakes of others, because you
> >won't live long enough to make them all yourself"
> >
> >
> >
> >
> >
> >LeRoy Westlund wrote:
> >
> >>Jim,
> >>Here are 3 posts that I saved on that bypass.
> >>I think you can use either 18K, or 27K resistors. The values are not
> >>critical.
> >>You can also shift the values to help balance the gray scale, due to one
> >>tube being weaker then the others.
> >>
> >>HTH,
> >>LLW
> >>
> >>**********************
> >>http://www.comunidadelectronicos.com/articulos/IK.htm
> >>
> >>This is the full article Jorge Miret of J.C. Electronic Repair posted
> >>recently. The modification uses 1N4148 diodes and is simple enough to
> >>implement right on the CRT board. Thanks Jorge.
> >>***********************************************************
> >>
> >>I tried this on a KV32S15 and it does work, value is not critical, I=
 used
> >>three 27K resistors. Like Jeff said, the picture fades in as the=
 filament
> >>warms up like a normal TV used to do and also the sleep/timer led no
>longer
> >>flashes as it warms up. This is NOT going to fix the weak gun of course
>but
> >>in some cases the owner could get another year or two out of the set=
 this
> >>way. Finally, a simple way to defeat the IK problem.
> >>**************************************************************
> >>
> >>Take three 18K resistors and connect one end of each to the Red , Green
>and
> >>Blue Cathodes , the solder the other ends all together.
> >>
> >>This works perfect , you can see the image come up as the filaments warm
>up.
> >>
> >>Image looks like crap because of the dead green cathode BUT picture is=
 not
> >>flashing....and that is all the customer wanted..
> >>
> >>LeRoy Westlund
> >>Westlund TV & Electronics
> >>97 North Main                                "Where there's a will,...
> >>Centerfield, UT 84622-0087           There's always a way."
> >>Ph./Fax  435-528-3822
> >>mailto:LLW@xxxxxxxxxx
> >>
> >>-----Original Message-----
> >>From: becyn <becyn@xxxxxxxxxx>
> >>To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx>
> >>Date: Tuesday, September 07, 2004 11:42 AM
> >>Subject: [TechAssist] Sony IK problem bypass
> >>
> >>
> >>
> >>
> >>>Hello,
> >>>A while back Someone had posted a drawing with text for this
>modification.
> >>>
> >>>
> >>I have a set here that I would like to try it on, but now i can't find=
 it.
> >>Anyone know where it is?
> >>
> >>
> >>>Jim McVey
> >>>McVey Alltronix
> >>>327 Broadway
> >>>Newburgh N.Y. 12550
> >>>
> >>>Factory authorized
> >>>service for over 20
> >>>major brands.
> >>>845 561 8383



Jorge Camboni, GY Electronics, Richardson, TX =20


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