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Philips 32PW6006/01 line stage shuts down after few seconds

 
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JamesQB



Joined: 23 Aug 2005
Posts: 26

PostPosted: Tue Aug 23, 2005 8:24 pm    Post subject: Philips 32PW6006/01 line stage shuts down after few seconds Reply with quote

Hi everyone,

I've got a sod of a TV set here which is puzzling me and I hoped that someone here more knowledgable than myself might be able to offer some advice.

It uses the L01.1E chassis and is a 32" widescreen. Originally it was tripping which turned out to be S/C line output transistor (or HOT as some call it), probable cause being C2455 (47uF/25V) in the line driver circuit, low in value at 36uF. This is apparently the usual cause with this chassis, and there is also a PSU kit available for the SMPS in the event that the set continually kills the line output transistor.

Anyway, replaced the transistor (BU4508DX) with a BU2508DF and replaced the cap with identical type. The set now comes on. I don't know if it's usual behaviour for this set, but it takes a while for the raster to appear, during which a couple of relays click. After 2 or 3 seconds or so, the set then shuts down. It seems the line drive is taken away when this happens, as the HT line rises from its value of 126V under load, to its 140V unloaded potential.

Although it shuts down quickly, I found that I could keep it on longer by going through the channels; it seems to stop the shut-down process. I brought up a channel with a very good undistorted image with no flaring, linearity or geometry errors, stopped flicking through the channels, leaving it on this one, and then the set died after a few seconds as normal. The transistor doesn't seem to be getting terribly hot during this.

The perfect picture during the short time it remains on leads me to believe there is little problem in respect to the line drive waveform. The two protection circuit activators are mentioned in the service manual and I have checked both voltages used to detect either high EHT or excessive beam current, and both are below protection circuit cut-out level. So, something else is causing the line stage to shut down, whilst the rest of the set remains active (HT level remains static), but it does not try to restart the line stage at any point, which is something it should do, according to the service manual, if the protection circuit has cut the line drive out, as the voltages then drop and the video stage then delivers horizontal drive once again.

I have substituted the line driver transistor, its associated push-pull transistor pair and the coupling eletrolytics, all to no avail. Something else is causing the line stage to be shut down, but what?

Any ideas or suggestions would be much appreciated as this has been on the bench too long now and I'm tired of its 32 inches taking up most of the workspace and falling over its gigantic rear cover!

Thanks to all who even read this, and especially to anyone who replies.

James


Last edited by JamesQB on Fri Aug 26, 2005 4:44 pm; edited 1 time in total
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Guest





PostPosted: Thu Aug 25, 2005 3:16 am    Post subject: Int. Philips Reply with quote

Hello,
Below find my only database entries for the fault you describe.

1/ TV set starts up and immediately switches to protection mode.

Check and if necessary replace diode 6467 for L01.1E and diode 6406
for L01.2E (5322 130 34331) on the Mono Carrier A.


2/ The set goes into protection.

Because the output voltage of the power supply unit is 130V instead of
140V, The set is going into protection due too high gain of IC7515.
Check and if necessary replace position 6541 on the Mono Carrier [A]
by BZX384-C9V1 (9322 150 08685).

Hope these might help,
John.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Thu Aug 25, 2005 4:59 pm    Post subject: Reply with quote

They make a repair kit.
1 - BU4508DX
1 - BC547
1 - BC557
1 - 47M/50V
1 - 220M/35V
See if this your problem.
Repair Kit
For Philips L01.1U
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JamesQB



Joined: 23 Aug 2005
Posts: 26

PostPosted: Fri Aug 26, 2005 1:09 pm    Post subject: Reply with quote

Hi,

Thank you for your kind help John.

Since it's chassis L01.1E, I will check diode 6406.

HT is fine at 140V. I will look for IC7515, I take it that it may need replacing?

I will also now check 6541 on the chassis.



Minnie, thank you also for your help.

That repair kit entry is interesting, but without chassis number references, I don't know exactly where the parts are for, although I can guess that the BC547 and BC557 are NPN and PNP replacements for the line driver push-pull transistor pair(?). Another problem is that the kit you mention is for the L01.1U chassis, whereas this here is the L01.1E type.
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JamesQB



Joined: 23 Aug 2005
Posts: 26

PostPosted: Fri Aug 26, 2005 1:10 pm    Post subject: Reply with quote

Sorry, I meant:

Since it's chassis L01.1E, I will check diode 6467.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Fri Aug 26, 2005 5:49 pm    Post subject: Reply with quote

Philips part #483531057554. This remote puts the tv into a service mode, or it should. My biggest pissers with philips newer stuff has been replacing the flyback. If the voltage is slightly off it will cause the tv to shut down. This modle is not listed yet on their force 32 program. But at least in the service mode the tv stay's on and allows you to be able to trouble shoot it. In most cases.
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Alessandrotecnic
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PostPosted: Tue Jul 01, 2008 9:58 pm    Post subject: Re: Philips 32PW6006/01 line stage shuts down after few seco Reply with quote

Hi...did you check the horizontal Transformers? check C2465,C2462,C2463, and the line 190V...

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JamesQB



Joined: 23 Aug 2005
Posts: 26

PostPosted: Sat Jul 04, 2009 2:33 am    Post subject: Reply with quote

I see someone sent me a private message about this set around 2 years ago. My email address on file is an old one as I'm no longer full-time in the business of repair.

After really testing my memory (this TV was in 4 years ago) I finally recalled what the trouble turned out to be and thought I should share, as it's annoying finding these posts with no outcome: the flyback (line output) transformer. Although it seemed okay when set was running for the short period before shutdown, a new line output transformer cured the problem of the line stage shutting down.
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