[TechAssist] Re: Samsung TXK2754 with repeat horizontal outputfailure
- From: "Christopher Barnak" <cbarnak@xxxxxxxxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Thu, 19 Feb 2004 07:24:55 -0500
Bob,
I think your HOT is blowing when the set is turned on or off. I would turn it
off every hour and let it sit an hour, then turn it back on an hour, etc. . My
gut feeling is you are not out of the woods yet. Sorry.
Christopher Barnak, CET
Norfolk Public Schools
School Plant Facilities
966 Bellmore Ave.
Norfolk, Va. 23504
Phone 757 628 3385
Fax 757 628 3392
cbarnak@xxxxxxxxxxxxx
>>> geminitv@xxxxxxxxxxxxxxxx 2/18/04 4:30:17 PM >>>
The parts used as I indicated in the original post are what is supposed to
be (and was actually inside) in the set from the factory. After replacing
the two electrolytics in the horizontal drive and the output transistor
again, the set is still running. I will let it run 24 hours a day throughout
the weekend at least.
Bob Waterman, CET® #RI-28
Master Technician License #9109
Service Manager / Parts Manager
Gemini Computer, TV, & Security Alarms
(508)695-7302
(508)695-7769 FAX
geminitv@xxxxxxxxxxxxxxxx
geminitv@xxxxxxx
www.geminicomputertvsecurityalarms.com
----- Original Message -----
From: "Technotronic Dimensions" <steve@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Wednesday, February 18, 2004 3:35 PM
Subject: [TechAssist] Re: Samsung TXK2754 with repeat horizontal output
failure
> The HOT (KSD5703) is a Non Damper Diode Type. Does the Schematic verify
> this?
>
> I think the Same thing can and will happen if say you place a Non damper
> Type HOT in place of one that requires it.
> Set will be ok for a while, then the cross conducting from C-E during the
> 'on' cycle, on what I think is counter EMF or other residual Signals in
> *SOME" circuits Designed as Such ....will cause Early HOT
> Retirement.....and there will be no sign of overheating, in most cases.
>
> You might want to Try a 2SC5149, that also has the 50 Ohm Resistor from
E-B
> as Well as a Damper, or NTE2353
> but its also possible you have another problem as yet undiscovered.
>
>
> Steve Hearns
> Technotronic Dimensions, NY [USA]
> www.TECHNOTRONIC-DIMENSIONS.COM
> 1-877-817-9885 (Voice / Fax Toll Free - US Only)
>
> ----- Original Message -----
> From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Tuesday, February 17, 2004 2:34 PM
> Subject: [TechAssist] Re: Samsung TXK2754 with repeat horizontal output
> failure
>
>
> Yes I did the obvious! I did replace C414 (220mfd/35v) off the primary of
> the horizontal driver transformer and also C427 (2.2mfd/250v) of the
> horizontal yoke winding this morning. I had ordered a couple extra HOTs so
I
> put a new one in and the set is running. The question is for how long?
>
> Bob Waterman, CET® #RI-28
> Master Technician License #9109
> Service Manager / Parts Manager
> Gemini Computer, TV, & Security Alarms
> (508)695-7302
> (508)695-7769 FAX
> geminitv@xxxxxxxxxxxxxxxx
> geminitv@xxxxxxx
> www.geminicomputertvsecurityalarms.com
>
>
> ----- Original Message -----
> From: "Webster TV" <webstertv@xxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Tuesday, February 17, 2004 1:56 PM
> Subject: [TechAssist] Re: Samsung TXK2754 with repeat horizontal output
> failure
>
>
> > Bob,
> >
> > Did you check the horiz. driver transformer for poor solder connections?
> > Have run into this on numerous different brands, the unit will run
> perfectly
> > until the connection opens up and then the H.O.T. will short
immediately.
> > Just a thought if you haven't checked this.
> >
> > Dan Webster
> > Webster's TV
> > Shullsburg, Wi.
> > ----- Original Message -----
> > From: "Gemini Computer & TV" <geminitv@xxxxxxxxxxxxxxxx>
> > To: "Techassist" <techassist@xxxxxxxxxxxxx>
> > Sent: Monday, February 16, 2004 7:04 PM
> > Subject: [TechAssist] Samsung TXK2754 with repeat horizontal output
> failure
> >
> >
> > > I currently have a Samsung TXK2754 that was serviced by another
servicer
> > in
> > > the past about 4 or 5 times for a dead set according to the customer
> (she
> > > recently moved into my area). I found the horizontal output transistor
> > > shorted and this had been replaced by the other servicer (I could find
> no
> > > evidence that any other parts had been replaced at any time). I
ordered
> > > parts directly from Samsung and installed them this past Thursday and
> the
> > > set ran continously until at least 1pm on Saturday when we closed (I
> came
> > in
> > > this morning and found the unit dead again with the output transistor
> > > shorted again). The B+ was rock steady at 135 volts, the horizontal
> > waveform
> > > was perfect, and the set was looking good prior to dying again. Here
is
> > the
> > > list of parts I replaced:
> > >
> > > Q401 (HOT) (KSD5703, Samsung # 0502-001136
> > >
> > > T444S (Flyback) (FUH-29A001A, Samsung# AA26-00013A)
> > >
> > > D805 (135 V rectifier) (F10U60S, Samsung# 0402-001358)
> > >
> > > Does anyone have some suggestions as to why the HOT keeps shorting
(and
> it
> > > is "normally" cool with no signs of overheating)?
> > >
> > > Bob Waterman, CET® #RI-28
> > > Master Technician License #9109
> > > Service Manager / Parts Manager
> > > Gemini Computer, TV, & Security Alarms
> > > (508)695-7302
> > > (508)695-7769 FAX
> > > geminitv@xxxxxxxxxxxxxxxx
> > > geminitv@xxxxxxx
> > > www.geminicomputertvsecurityalarms.com
> > >
> > >
> >
>
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