technika 17pw 26-3 power issue

[arc2002]

Hi guys,
i have search the forum and thankfully found the correct schematic for my PW17 26-3, my problem is as follows.
when turned on the standby light does not come on and the tv is effectively dead, but when i check the voltages to socket PL816 I do get some readings,
After changing a couple of caps on the original board i gave up and simply purchased a replacement 'used' but working board from ebay, UNFORTUNATELY that did not solve the issue either.
With both board the same problem, effectively an unresponsive tv, that is until i unplug it from the mains when momentarily the standby light will flash for a few milliseconds.
In terms of physical condition none of the caps look blown, i have tried physically stressing the boards to see if solder cracks are causing an issue but again no joy, any and all help to get this beast fired from the group up would be appreciated.
Please see attachment for my Vin's

P.s my son while persistently unplugging and pluging the tv back into the wall socket is able to fire the thing up but that takes him 15mins of relentless plugging....
I do actually get a tone from each of the tvs buttons when they are pressed.

Cheers
Ian

[vinceroger69]

Re: technika 17pw 26-3 power issue

This maybe a mainboard issue i guess whats the tv full model number and whats the mainboard number?

[arc2002]

Re: technika 17pw 26-3 power issue

Hi Vince,
many thanks for replying, the details are
Tv model number :LCD32-209V
mainboard number :458073 98843 (UK8.14 L6HY)

[vinceroger69]

Re: technika 17pw 26-3 power issue

This is a tesco set if i remember the last one like this ive done was a faulty mainboard let one of the more experienced members check the voltages etc, but if it does require a main board try to get a exact match.

[newtothis]

Re: technika 17pw 26-3 power issue

So you can hear sound when powered on but no picture yes?

[arc2002]

Re: technika 17pw 26-3 power issue

So you can hear sound when powered on but no picture yes?

Hi,
no picture the only sound i get is from pushing the function buttons, which is the bleep tone to indicate the buttons have be pressed.

is their a shcematic available or this mainboard?

Ian

[Alastair E]

Re: technika 17pw 26-3 power issue

One of Tescos finest turds, the Technika/Vestel 32-209x

Sounds like the F/W of the mainboard is suspect, Vestel F/W is flaky at best, can cause all sorts of weird faults.

There is a way to re-write the sets own F/W by using a USB stick and going into the serrvice-menu, there's an option to copy out the F/W--But your prob is the set wont fire up--Job for your son--Get it running, then access the service-menu.....

On that Mainboard, there should be a number like 17MBxx

Vestel M.B can be difficult to replace--as they are very model specific due to the screen. You HAVE to get the Exact one or it wont drive the (whatever make and Model) LCD Panel it has....

[arc2002]

Re: technika 17pw 26-3 power issue

thanks Alastair,
the board is marked 17MB25-3 , hmm firmware , i am familiar with doing those
is their any chance of reaching a secret service menu via the tv's panel buttons while powering up, and is their a schematic for this mainboard...just so that i prod around checking voltages?

many thanks
ian

[ReeceyBurger123]

Re: technika 17pw 26-3 power issue

I will be honest ive actually seen plenty of the standby led diodes fail, normally when the motherboard goes bad check that first and see if voltage is going to that.

[newtothis]

Re: technika 17pw 26-3 power issue

According to his images he has no BL_ON voltage

[arc2002]

Re: technika 17pw 26-3 power issue

I will be honest ive actually seen plenty of the standby led diodes fail, normally when the motherboard goes bad check that first and see if voltage is going to that.

Hi Reecey,the standby diodes do work but i only ever see them briefly flash as disconnect from the 240v mains.
Aside from the BL_ON Vin being missing i also have 33v missing from pin 13 does this offer any clues to my issue's?
Would it be possible to bridge any of the missing Vin's to see if physically making them High works?
Ian

[ReeceyBurger123]

Re: technika 17pw 26-3 power issue

Hi Reecey,the standby diodes do work but i only ever see them briefly flash as disconnect from the 240v mains.
Aside from the BL_ON Vin being missing i also have 33v missing from pin 13 does this offer any clues to my issue's?
Would it be possible to bridge any of the missing Vin's to see if physically making them High works?
Ian

Ok, sounds like a main-board fault then probably firmware or failed voltage regulator. I will try and find a schematic for the board.

[vinceroger69]

Re: technika 17pw 26-3 power issue

wrong post please ignore.

[arc2002]

Re: technika 17pw 26-3 power issue

Hi Fellas,
i was unable to find a schematic for the mainboard, but with closer inspection (put my glasses on) i was able to read the capacitor numbers/board locations and their Vin's, so have now put together a rough drawing (please see attachments) of the board including the corresponding cap numbers and Vins, in my drawing i have underlined the values i see with my multimeter, i did all he readings using a single common board GRD, so looking back if these voltages are all deemed to be correct i still could have a broken GND to a particular capacitor.

I noticed that of all the caps C843 rated at 16v does seem very low at 1.8v, but as this was located next to the Common interface card reader i assume it was related to that unused device.

Board header CN119 is the five pin socket that leads to the standby LED diode's, here i see 0volts at pins 1 to 3, and 2.2v at pins 4 & 5.


Many thanks for the advice so far,and still looking forward to more.

Ian

[newtothis]

Re: technika 17pw 26-3 power issue

Without knowing the traces it doesn't really tell us much.

Mainboards are bitches to repair even with a schematic!

My advice is to try flashing it like mentioned earlier

[arc2002]

Re: technika 17pw 26-3 power issue

Hi Guys,
small problem with the firmware update, my set does not have a usb port...

I did manage to get the standby light to come on, the problem was a dry contact at Pin 4 (next to the gray with red tracer wire) at header CN115.

The set still refused to boot up, Iguess this will be either down to a corrupt FW or as pointed out previously the lack of Vin at BL_ON.
So a new mainboard and power supply has been purchased.

update to come when they arrive.

Ian

[arc2002]

Re: technika 17pw 26-3 power issue

Hi Guy,
good news is that the tv is now working as it should (see attachment), bad news is rather be able to say i tracked down and fixed an issue or two i have to admit that all i ended up actually doing was replacing the mainboard and psu which i purchased from Owen at tvpartsuk (who is a star by the way) all in all the fix cost me around £18.00 mostly due to Owen sending me out a free mainboard after experiencing issues with the first psu board he sent.

Many thanks for ALL your help fellas it really was appreciated.

Ian

[newtothis]

Re: technika 17pw 26-3 power issue

Well for $18 you can't really moan can you

Thanks for the follow up

[arc2002]

Re: technika 17pw 26-3 power issue

cheers nope, not until i left it on standby for an hour or so only to find out that its now stuck in that mode arggg
not evena bleep from the tvs side buttons now!!!
oh well back to the drawing board!!!

Ian

[newtothis]

Re: technika 17pw 26-3 power issue

May be a dodgy PSU or main you got... Lets go over voltages on the PSU.

Again list the voltage you get at the connector PL816

Have you tried the old PSU to see if that works?