[TechAssist] Re: Sony KP61XBR300 ---Repeat IK failure
- From: "Damon" <DAMON101@xxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 14 Jan 2002 20:39:07 -0500
Well, near 0 beam current set my green cathode IK pulse to 40 vpp. A 20 vpp
Ik gives me "slight green". Gonna have to go back and try 25 vpp, then 30
vpp if I have to. But the coarse adjust or "set to black on TV/Video"
procedure has proven itself to be a lot of hooey.
I agree about the cutoff , those new crts should be able to put out a good
pulse and have the black picture on TV/Video, I'll bump down the black
pedestal using my digital meter to take a reading first, then bump it down a
volt or two.
Damon Brunger
damon101@xxxxxxxxxxxxxx
Telrad Electronic Services
Ft Wayne, IN 46815
----- Original Message -----
From: "Dennis Viereck" <wa6ati@xxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Sunday, January 13, 2002 12:24 PM
Subject: [TechAssist] Re: Sony KP61XBR300 ---Repeat IK failure
>
> Damon:
>
> Great antidote on the fix or possible fix. When you set the drives did you
ever
> loose the slight green raster in the at the tube? I always thought, that
when in
> the video input mode, and no video excitation, that each tube will be at
"0" or
> "near 0" beam current. With a slight green raster you have to be pulling
some
> beam current.
>
> Dennis Viereck
>
> Damon wrote:
>
> > Thanks Dennis, your info was on target.
> >
> > I found the green Ik pulse on the cathode was 40vpp. Also I changed the
> > setup procedure, my mistake was trying to set the screens on a
signal-less
> > video input to black, rather than setting the black pedestal to 175
volts
> > using a scope. I find when I set that properly, I had a "slightly
green-no
> > picture" condition on video input. That bugged me.
> >
> > Anyways, when I set the pedestal to 175 Volts, my cutoff and drive
> > adjustments on the Blue CRT now seem to mirror the Red and Green
adjustments
> > (my blue was about 60 and red/green about 30 when bad, now all are 35).
> >
> > Now I don't want to say this PTV is fixed yet, it has been intermittant
> > since last March, but I do know that the setup on these Crts are right
on
> > target. The IK pulse on all 3 Crts are now 20Vpp.
> >
> > Thanks for the info.
> >
> > Damon Brunger
> > damon101@xxxxxxxxxxxxxx
> > Telrad Electronic Services
> > Ft Wayne, IN 46815
> > ----- Original Message -----
> > From: "Dennis Viereck" <wa6ati@xxxxxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Thursday, January 10, 2002 9:47 AM
> > Subject: [TechAssist] Re: Sony KP61XBR300 ---Repeat IK failure
> >
> > >
> > > Damon:
> > > I've only had CRT's and the IK buffer transistor, which there are 1 on
> > each module. When the set is in the failed condition, what amplitude
does
> > the IK pulse have on the cathode of each CRT, after ample time has been
> > given to warm the filaments? If you suspect the blue CRT I would start
> > there. Finally are you getting all three IK pulses fed back to the RGB
> > processor?
> > >
> > > I have had problems with the CRT's where the IK pulses at the cathode
were
> > unusually high 45~ 55 volts peak to peak where the other two are 20~ 30
> > volts peak to peak. But in the sam instance the IK feed back looked
normal
> > with all pulses within 10 ~ 15% of each other. Swapping that tube
brought
> > the IK pulse back to the 20 ~ 30 v pp.
> > >
> > > As for the HV block and the possibility of it causing an IK failure: I
> > don't think that it would be reasonable. Any internal leakage that would
> > load down the high voltage on 1 output would load down the output of the
> > high voltage transformer too. This will increase in current would cause
an
> > over beam current shut down, not a IK error.
> > >
> > > Dennis Viereck
> > >
> > > Damon wrote:
> > >
> > > > Hello All,
> > > >
> > > > My question is : has anybody had a problem with the HV Splitter or
the
> > Power supply causing an IK failure to be registered?
> > > >
> > > > I have had a nightmare with this TV. First, this problem occurs
> > intermittantly, the IK pulses do not reveal one specific tube as being
bad.
> > > >
> > > > I've replaced and upgraded the BD board, all 3 CRT boards, and all 3
> > CRTs. Yet the problem remains. The customer has stated that before the
> > picture blanks and the light starts to blink 5 times, the OSD pops up.
Also
> > if he is changing channels the picture will blank intermittantly.
> > > >
> > > > Recently he is getting a green shifting of color before blanking.
Also,
> > the cutoff settings for the blue crt (new) are set at about 60 in
comparison
> > to the 30 setting for the RED/Green crts. I discovered on the last trip
that
> > his green anode connection was not mechanically connected to the HV
> > Splitter, I reconnected that (that's when the green shift started
> > occurring). This TV is too big to load in the van because it's too wide.
> > > >
> > > > I've checked the wiring, grounds, adjusted the screen controls,
cutoff
> > and drive settings in various configurations to increase the IK pulse
output
> > (it's not a flat-topped pulse, seems to have a slight curve to the
leading
> > edge).
> > > >
> > > > Have you seen any out-of-the-ordinary problems causing this? Has
anybody
> > recieved a defective CRT from Sony (that blue Crt bugs me). How about a
bad
> > splitter (internal resistance higher on one leg)? Anybody had a power
supply
> > that checks good but has caused IK failures ONLY to register?
> > > >
> > > > Damon Brunger
> > > > damon101@xxxxxxxxxxxxxx
> > > > Telrad Electronic Services
> > > > Ft Wayne, IN 46815
> > > >
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