[TechAssist] Re: Mitsubishi VS 5006 repeat vert fail???
- From: "Damon" <damon101@xxxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Fri, 21 Sep 2001 20:53:03 -0500
I went back out with a different Vert output (yes the first ones I used were
SK) and unfortunately the same exact voltages were seen with an ECG. I
backtracked on my troubleshooting and discovered my 130 v supply was running
at 75volts, a quick check of the Horiz output indicated it was running hot.
I loaded the power supply and it tested good, the horiz output /caps/diodes
tested good, and about the only thing left was the IHVT. I gotta go back and
test the yokes for possible shorts to the neck of the crts, and pull the
IHVT for a ring test. So at this point, it's either the Yoke(s) or the IHVT
and I have not seen either of these problems in this chassis. Worse yet, if
it is the IHVT, Part # 334P191020 is no longer available, and no substitutes
as far as I know. Will keep you folks updated.
----- Original Message -----
From: "Shoreline Electronics" <jstielau@xxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, September 20, 2001 8:06 AM
Subject: [TechAssist] Re: Mitsubishi VS 5006 repeat vert fail???
>
> Damon,
>
> I'd try another Vert Output IC to be sure ( Different batch....no
SK's!!!)
> Also...my notes show the zener should be an 11V...not a 10V.
>
> Jeff Stielau
> Shoreline Electronics Repair
> 125 Beechtree Lane
> Westbrook,CT 06498
> 860-399-1861 Voice
> 860-664-3535 Fax
> jstielau@xxxxxxxx
>
> ----- Original Message -----
> From: "Damon" <damon101@xxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Thursday, September 20, 2001 2:35 AM
> Subject: [TechAssist] Mitsubishi VS 5006 repeat vert fail???
>
>
> > Hello everybody,
> >
> > I have a VS 5006 that had a dead vertical Ic about 2 weeks ago. I had
> replaced the LA 7838 vertical output, along with c4000 and c4006 which are
> the 28 volt power supply filtering caps, the 10 volt zener diode on pin 1
of
> the ic, and also had a dead SMPS output ic which isn't even associated
with
> the vertical circuit. When I installed the new vertical ic, it didn't even
> work, fortunately I had another one, installed it and it ran fine for 2
> weeks. Now I'm back on the job again with a dead vert ic and wondering if
I
> ran into a bad batch of LA7838's or if I'm missing something on this
repair.
> >
> > Here's what I'm seeing: 10 volts is present on Pin 1, sync is present on
> pin 2, my 28 volt supply is running at 14 volts (this uses a 28 v Ihvt
> supply) and the diode and resistor on the 28 v supply measure good. Looks
> like the vert output is loading down the 28v supply, but nothing is
smoked.
> the vert yokes each measure 2 ohms for a total of 6 ohms, so I don't think
I
> should be looking at that..... Any body had any problems like this? The
vert
> pump up diode measures ok too.
> >
> > Thanks to anybody who has seen this problem and can resolve this.
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