beko 32WLZ530HID backlight flashing/flickering

[wills123]

hoping for some help with this one, its psu has the inverter built into,
ipos150b-rev 3.2. Beyond replacing obvious bad caps i havent really done much component level diagnosing,hoping to learn

Anyway the tv switches on, then the back light flicks on then off at about 1-2 sec intervals very consistantly as though being switch on off.

measuring voltage over the main cap on the board its stable at standby, but when switched on raises to 257v then switches to 290v at 1-2sec intervals. It does this with or without the backlights plugged so i dont think the backlights themselves are the issue.
was thinking maybe the main cap bad but would it really switch that consistantly? thanks for any help,
have included some pictures of the psu

[multimeter]

Re: beko 32WLZ530HID backlight flashing/flickering

hoping for some help with this one, its psu has the inverter built into,
ipos150b-rev 3.2. Beyond replacing obvious bad caps i havent really done much component level diagnosing,hoping to learn

Anyway the tv switches on, then the back light flicks on then off at about 1-2 sec intervals very consistantly as though being switch on off.

measuring voltage over the main cap on the board its stable at standby, but when switched on raises to 257v then switches to 290v at 1-2sec intervals. It does this with or without the backlights plugged so i dont think the backlights themselves are the issue.
was thinking maybe the main cap bad but would it really switch that consistantly? thanks for any help,
have included some pictures of the psu

the voltage on the large filter cap when turned on is way to low,it should be reading around 380VDC,which it may have lost its capacitance,a quick check with an ESR meter can rule it out at least.

its most probably running out of tolarance and barely firing up the psu,

or there could be a shorted diode on the output side.

re-soldering the inverter transformers will do good as well,(can be a cause of flickering)

[wills123]

Re: beko 32WLZ530HID backlight flashing/flickering

thanks for trying to help, unfortunately i dont have an esr meter(i really should invest in one), i can find two normal diodes at d23 and 24 test ok using diode function on meter. theres a zener diode at z6 next the blue cap that im unsure as it gives a reading both ways, need to remove from circuit to check? and what i think is a 3 leg diode at d6 that im also unsure about, also need to remove from circuit?
thanks

[wills123]

Re: beko 32WLZ530HID backlight flashing/flickering

update, i desoldered the zener diode , the diode part tests fine out of circuit, ive ordered a main cap to try hopefully its that, can anyone recomend a good esr meter? its about time i got myself one thanks

[vlado64]

Re: beko 32WLZ530HID backlight flashing/flickering

Tip for appliances using the IPOS-150 PSU. Replace IC7 (plug-in type

[vlado64]

Re: beko 32WLZ530HID backlight flashing/flickering

I have this LCD meter
http://www.ebay.com/itm/Handheld-LCR...item3f324789b9

[wills123]

Re: beko 32WLZ530HID backlight flashing/flickering

that meter looks good but bit pricey for me , i have a reasonable dmm, looking at theese, http://www.ebay.co.uk/itm/2613526308...84.m1423.l2649
im not looking to rebuild a rocket/space station/nuclear warhead, lol
will they suffice for general testing on consumer electronics?
i tinker with t.v.dvd,xbox,ps3 etc thanks

[wills123]

Re: beko 32WLZ530HID backlight flashing/flickering

new main cap fitted, voltage is now steady 390v across it but the problem with the back lights switching on an off is still there