Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting TVs and Video Sources
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 03-26-2016, 04:34 AM   #1
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Bought this in the hope of fixing would like some pointers.

When i plug in mains chord I get 2 clicks from the relay. (sounds about right to me) When i try an get the tv out of standby, a relay clicks the i get 3 flashes from red led on PSU.

|v'e done a visual inspection and can't find anything suspicious.

There are some pen markings on some of the Ybuffer ICS??
Attached Images
File Type: jpg IMAG2732.jpg (2.37 MB, 22 views)
File Type: jpg IMAG2733.jpg (2.79 MB, 19 views)
File Type: jpg IMAG2734.jpg (2.33 MB, 11 views)
File Type: jpg IMAG2735.jpg (2.45 MB, 14 views)
File Type: jpg IMAG2736.jpg (2.22 MB, 12 views)
File Type: jpg IMAG2737.jpg (1.76 MB, 11 views)

Last edited by niblettr; 03-26-2016 at 04:36 AM..
niblettr is offline   Reply With Quote
Old 03-26-2016, 04:38 AM   #2
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Hello these are great Tv's deffo worth repairing. Does the standby light on the front of the Tv give any flashes ? If so are they red or blue and how many does it give ?
__________________
Please Do Not PM My Page Asking For Help Badcaps Is The Place For Advise, Page Linked For Business Reasons Only. Anyone Doing So Will Be Banned Instantly !

https://www.facebook.com/Telford-Tel...7894576335359/
ReeceyBurger123 is offline   Reply With Quote
Old 03-26-2016, 04:49 AM   #3
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

red and orange when in stanbye,
red and blue with fault then contiuous 2 red flashes
niblettr is offline   Reply With Quote
Old 03-26-2016, 05:18 AM   #4
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

2 red is a Ydrive failure which causes the Vs rail to be dragged down on the Psu therefore locking out the Psu. If you unplug the Y and Xdrive what happens does the Tv flash another fault code ?
ReeceyBurger123 is offline   Reply With Quote
Old 03-26-2016, 06:18 AM   #5
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

No change, same flash codes.
niblettr is offline   Reply With Quote
Old 03-26-2016, 08:33 AM   #6
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Ok now time to start checking the voltage rails from what they are stated as on the connectors.
ReeceyBurger123 is offline   Reply With Quote
Old 03-26-2016, 01:51 PM   #7
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Quote:
Originally Posted by ReeceyBurger123 View Post
Ok now time to start checking the voltage rails from what they are stated as on the connectors.
Ok, got no VSUS even when isolated. PSU fault?
niblettr is offline   Reply With Quote
Old 03-26-2016, 02:18 PM   #8
tom66
EVs Rule
 
tom66's Avatar
 
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Professional Tech
Posts: 32,373
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Seems likely
__________________
Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
Free service manuals: http://www.toms-service-manuals.com/ -- 72 LED/LCD TVs, 5 monitors, 28 plasma TVs, and 2 AVR 6.1 amplifiers fixed! -- I repair Pioneer 9G Plasma Main Boards & KRP-M01 Media Receivers (PM me for info)

2 Pioneer KURO 9G, 12 Panasonic LCD/Plasma, 1 Sony LCD, 1 NEC Plasma, 2 Yamaha HTS, 5 Sharp LCDs, 5 Toshiba LCDs, 7 Philips Plasma/LCD, 1 Hitachi Plasma, 11 LG LCD/Plasma, 18 Samsung LED/LCD/Plasma, 1 Thomson Plasma, 1 Atec LCD, 1 Hanspree LCD, 1 Xerox LCD, 1 Harwa LCD, 2 Proview LCD, 2 Hyundai LCD, 1 "Onn" LCD, 1 Grundig LCD, 1 Dell LCD, 1 iiyama LCD, 1 Acer LED, 1 Logik LCD, 1 Baird (China) LCD, 6 Bush LCDs, 22 Vestel LCDs (Best->Worst)
tom66 is offline   Reply With Quote
Old 03-26-2016, 05:38 PM   #9
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

ok, found 2x K3314 FETS that are shorted on the middle heatsink on the PSU.
I've whipped them out and double checked and there are shorted. Ordered some new one.
Bit worried that something further upstream may be bust.
I checked some sot23 transitors that looks like may be driving these fets and they checked out ok but 2 diodes measured a bit odd. I got 0.6v drop in both directions....
niblettr is offline   Reply With Quote
Old 03-26-2016, 05:40 PM   #10
tom66
EVs Rule
 
tom66's Avatar
 
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Professional Tech
Posts: 32,373
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

You should replace the driver chip (connected to the FETs) and the fuse as well.
tom66 is offline   Reply With Quote
Old 03-26-2016, 05:45 PM   #11
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Probably just the fets quite common on Plasma supplies due to the way they are loaded at start up. Also replace the fuse and should be fine
ReeceyBurger123 is offline   Reply With Quote
Old 03-26-2016, 05:57 PM   #12
tom66
EVs Rule
 
tom66's Avatar
 
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Professional Tech
Posts: 32,373
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Quote:
Originally Posted by ReeceyBurger123 View Post
Probably just the fets quite common on Plasma supplies due to the way they are loaded at start up. Also replace the fuse and should be fine
You should know now that it is a bad idea to just replace the FETs! Also the startup loading isn't a big deal (just charging the caps, but there is a current limit for a reason.)
tom66 is offline   Reply With Quote
Old 03-26-2016, 06:03 PM   #13
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Alot of the time in my case the driver has almost never ever been damaged at all Tom. Normally if the Vcc and other input pins have no shorts or low resistance across them or to ground it will be ok. I personally have only had to replace 1in 10 drivers for the repairs like this.

It might come back and bit me on the ass but I will sort it.
ReeceyBurger123 is offline   Reply With Quote
Old 03-26-2016, 06:06 PM   #14
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

thanks for all the input so far.
What fuse?
niblettr is offline   Reply With Quote
Old 03-26-2016, 06:08 PM   #15
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

note I also removed the transformer so that I could get to the screws holding the fets to the heatsink.
Attached Images
File Type: jpg IMAG2739.jpg (940.0 KB, 22 views)
File Type: jpg IMAG2741.jpg (1.09 MB, 14 views)
niblettr is offline   Reply With Quote
Old 03-26-2016, 06:09 PM   #16
tom66
EVs Rule
 
tom66's Avatar
 
Join Date: Apr 2011
City & State: Leeds
My Country: UK
Line Voltage: 230Vac 50Hz
I'm a: Professional Tech
Posts: 32,373
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Quote:
Originally Posted by ReeceyBurger123 View Post
Alot of the time in my case the driver has almost never ever been damaged at all Tom. Normally if the Vcc and other input pins have no shorts or low resistance across them or to ground it will be ok. I personally have only had to replace 1in 10 drivers for the repairs like this.

It might come back and bit me on the ass but I will sort it.
For me it's much higher - around 1 in 3 have shown suspect readings - although it does depend on the topology of the supply. Flyback and half bridge is more likely to damage the driver. Flyback due to high peak drain voltages, half bridge due to floating source node
tom66 is offline   Reply With Quote
Old 03-26-2016, 06:34 PM   #17
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Quote:
Originally Posted by tom66 View Post
For me it's much higher - around 1 in 3 have shown suspect readings - although it does depend on the topology of the supply. Flyback and half bridge is more likely to damage the driver. Flyback due to high peak drain voltages, half bridge due to floating source node
Thats true, I have been lucky so far but I always check them any way Tom I know what too look out for. I guess there is the cases of the controller becoming intermittent as I have had before but thats rare for SMPS tbh.
ReeceyBurger123 is offline   Reply With Quote
Old 03-26-2016, 06:34 PM   #18
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Sorry guys, what fuse? Do you mean the sub ohms ceramic resistors?
niblettr is offline   Reply With Quote
Old 03-26-2016, 06:34 PM   #19
niblettr
Member
 
niblettr's Avatar
 
Join Date: Jun 2015
City & State: bournemouth
My Country: UK
Line Voltage: 230AC 50Hz
I'm a: Hobbyist Tech
Posts: 88
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Sorry guys, what fuse?
niblettr is offline   Reply With Quote
Old 03-26-2016, 06:58 PM   #20
ReeceyBurger123
Never Give Up !
 
ReeceyBurger123's Avatar
 
Join Date: May 2014
City & State: Telford
My Country: Britain
Line Voltage: 240 VAC 50Hz
I'm a: Student Tech
Posts: 7,124
Default Re: Pioneer PDP-LX508D Won't turn on, 3 flashes from PSU

Normally for the Vs fets its in between the filter caps or behind the fets. It might be a ceramic style can fuse.
ReeceyBurger123 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 01:45 AM.
Did you find this forum helpful?