[TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off

From: "mike wilson" <mykeelike@xxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Date: Mon, 6 Jan 2003 11:52:08 -0800
I have seen tons of problems with set but I havent seen this one before. but
I think the collector voltage that you described on q433 in off state should
be zero.either q433 is not being driven enough via r403 4.7k or the ground
is open on the emitter. what happens if you short the collector of q433 to
ground?if pin 2 of ic 402 does not go low check r433 330 ohm.

mike wilson
am stereo & video
seattle wa.
206 364 5904

----- Original Message -----
From: "dolph1133" <dolph1133@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, January 06, 2003 8:10 AM
Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off


>
> Is relay energized ?
>
> Adolph Gower
> Cordova TV
> 10275 Old Placerville Rd. #5
> Sacramento, Ca. 95827-3044
> Phone (916) 363-6565
> Fax (916)363-7623
> Email:dolph1133@xxxxxxxxxxx
>
> -----Original Message-----
> From: techassist-bounce@xxxxxxxxxxxxx
> [mailto:techassist-bounce@xxxxxxxxxxxxx]On Behalf Of D Thunhurst
> Sent: Monday, January 06, 2003 6:29 AM
> To: techassist@xxxxxxxxxxxxx
> Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
>
>
>
> Yes I did change this zener.  I had 5.2v on the old one and now I have
5.6v
> on the new one.  Still no help.
> Daryl
> Daryl's TV
> 3310 Dyer St.
> El Paso, TX 79930
> 915-565-9184
> 915-564-1024 Fax
> http://dynacomp.freeyellow.com
> -----Original Message-----
> From: Gemini Computer & TV <geminitv@xxxxxxxxxxxxxxxx>
> To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx>
> Date: Monday, January 06, 2003 6:14 AM
> Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
>
>
> >
> >Did you replace Z430? The original part number of 5303000001 is in the
old
> >10NC Philips part number format while the "new" part number 483513097005
is
> >the 12NC part number system.
> >
> >Bob Waterman, CET® #RI-28
> >Master Technician License #9109
> >Service Manager
> >Gemini Computer, TV, & Security Alarms
> >(508)695-7302
> >(508)695-7769 FAX
> >geminitv@xxxxxxxxxxxxxxxx
> >geminitv@xxxxxxx
> >
> >----- Original Message -----
> >From: "D Thunhurst" <dthunhurst@xxxxxxx>
> >To: <techassist@xxxxxxxxxxxxx>
> >Sent: Friday, January 03, 2003 7:00 PM
> >Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
> >
> >
> >>
> >> Bob,
> >> Thanks so much for your reply.
> >> With a bit of embarrassment, I was interrupted several times while
trying
> >to
> >> post this problem that I failed mention I already replaced IC400 and
> >IC402.
> >> I also replaced C459 and C431.  I also resoldered the usual poor solder
> >> joints that these sets all have.  I checked as suggested, C421, C430,
> R427
> >> and R428.  My voltages on Q433 are:
> >> C=9.2
> >> B=0
> >> E=0
> >> this is with the set in the "on" mode.
> >> C=8.4
> >> B=.6
> >> E=0
> >> this is in the "off" mode.
> >> There is 9.4v on P2 of IC402 with no change in voltage in "on" or "off"
> >> mode.  I would definitely say that IC402 is the culprit but I did
already
> >> change it to no avail.  You mentioned that the 483513097005 replaces
> >> 5303000001.  Is this possibly an upgrade for this problem as I had the
> old
> >> number in stock.
> >> This seems to be the only problem with this set.  Everything else is
> >working
> >> properly.
> >> Again, thanks for your help.
> >> Daryl
> >> Daryl's TV
> >> 3310 Dyer St.
> >> El Paso, TX 79930
> >> 915-565-9184
> >> 915-564-1024 Fax
> >> http://dynacomp.freeyellow.com
> >> -----Original Message-----
> >> From: Gemini Computer & TV <geminitv@xxxxxxxxxxxxxxxx>
> >> To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx>
> >> Date: Thursday, January 02, 2003 6:37 PM
> >> Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
> >>
> >>
> >> >
> >> >First thing to do is replace IC402 (optoisolator IC). It is part #
> >> >483513097005 (formerly part# 5303000001). If that does not take care
of
> >it,
> >> >then check Z430, C421, C430, R427, R428, Q433, and IC400. I am almost
> >> >certain this should cure it. let us know how you make out.
> >> >
> >> >Bob Waterman, CET® #RI-28
> >> >Master Technician License #9109
> >> >Service Manager
> >> >Gemini Computer, TV, & Security Alarms
> >> >(508)695-7302
> >> >(508)695-7769 FAX
> >> >geminitv@xxxxxxxxxxxxxxxx
> >> >geminitv@xxxxxxx
> >> >
> >> >----- Original Message -----
> >> >From: "D Thunhurst" <dthunhurst@xxxxxxx>
> >> >To: <techassist@xxxxxxxxxxxxx>
> >> >Sent: Thursday, January 02, 2003 7:50 PM
> >> >Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
> >> >
> >> >
> >> >>
> >> >> Thanks for the reply.
> >> >> Is this the famous 100@200v cap you have reference to?  If so, this
> set
> >> >> doesn't use it.  C432 on this set is a .1@50v cap.
> >> >> Daryl
> >> >> Daryl's TV
> >> >> 3310 Dyer St.
> >> >> El Paso, TX 79930
> >> >> 915-565-9184
> >> >> 915-564-1024 Fax
> >> >> http://dynacomp.freeyellow.com
> >> >> -----Original Message-----
> >> >> From: TV Doctors <tvdoctors@xxxxxxxxxxxxx>
> >> >> To: techassist@xxxxxxxxxxxxx <techassist@xxxxxxxxxxxxx>
> >> >> Date: Thursday, January 02, 2003 4:55 PM
> >> >> Subject: [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
> >> >>
> >> >>
> >> >> >
> >> >> >
> >> >> >Change C432
> >> >> >-------Original Message-------
> >> >> >
> >> >> >From: techassist@xxxxxxxxxxxxx
> >> >> >Date: Thursday, January 02, 2003 01:59:09 PM
> >> >> >To: TechAssist
> >> >> >Subject: [TechAssist] Magnavox RK5554, 27P1 ch....can't turn off
> >> >> >
> >> >> >Hi,
> >> >> >This Magnavox is eating my lunch. The set comes on at plug in. The
> >relay
> >> >> >is used solely for degauss. The on-off circuit is controlled by the
> >> micro
> >> >> >and is giving me "0" volts in the "on" position and ".6" volt at
turn
> >> >off.
> >> >> >I have replaced Q430, Q431, Q432, Q433, Z430, R437, C435, and C436.
> >> >> >The schematic shows that the base of Q432 is connected to the micro
> >and
> >> I
> >> >> am
> >> >> >getting the biasing on that transistor (marked as on-off switch).
> >> >> >This set is very sensitive to temperature. When components are
> heated,
> >> >the
> >> >> >set can be turned off.
> >> >> >A simple solution you say?? I thought so too!!
> >> >> >Every component I stated I replaced was because when I would place
> the
> >> >tip
> >> >> >of the soldering iron just close to each of the various components,
> >the
> >> >set
> >> >> >would function properly. Freeze the parts and the set could not be
> >> turned
> >> >> >off.
> >> >> >I even mounted the parts in question on the bottom of the board as
> not
> >> to
> >> >> >heat or cool any other part and thought to have confirmed the
> culprit.
> >> >> >After replacing the part or parts in question using OEM parts, the
> >same
> >> >> >symptom occurred, even with the new parts, absolutely no change.
> >> >> >I am now at a loss as I have replaced or subbed every part that was
> >> >> effected
> >> >> >by heating and cooling. Now I know how a new born calf looking at a
> >gate
> >> >> >must feel.
> >> >> >Any ideas or advice would be appreciated.
> >> >> >Thanks
> >> >> >Daryl
> >> >> >Daryl's TV
> >> >> >3310 Dyer St.
> >> >> >El Paso, TX 79930
> >> >> >915-565-9184
> >> >> >915-564-1024 Fax
> >> >> >http://dynacomp.freeyellow.com
> >> >> >
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References:
- [TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off
  - From: dolph1133
[TechAssist] Re: Magnavox RK5554, 27P1 ch....can't turn off

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