Techwood 32HDMPEG4 IDTV

[JonathanAnon]

Hi lads,

The power board was bad on this, loads of components blown, so I didnt even attempt a repair. I bought another PSU ... 17PW25-3 .. I installed it and all the voltages are all back on track, on both the inverter connector and the main board connector voltages are good... BUT it's just not coming on...

I click the button on the side panel and it beeps, which indicates that the main board is working to some extent... However, I have no led on the front, and I've plugged in a scart lead with a DVD playing and I'm not getting sound (so it's not just backlight issue)..

I've removed the main board cable and I'm trying to trigger the backlight on, to confirm that the inverter board is good (which I think it actually is) but when I jumper the BL_ON to GND on the PSU, it's not coming on. There's is no PS_ON, do I need to jumper the SOFT_SWITCH to GND as well ?



Any advice must appreciated

[tom66]

Re: Techwood 32HDMPEG4 IDTV

Vestel light LED in standby, turn it off in operation. So no LED may be normal.

[JonathanAnon]

Re: Techwood 32HDMPEG4 IDTV

Okay on further investigation.. I plugged out tcon and main, and found the following.

5v rails - These are perfectly stable at 5.22v
12v rails - These are hanging at 10.7 (11% less than where it should have been) . With a dummy load of 0.6A / 12V in the form of two fans, it holds stable at 10.7v, which even given the tolerance is low...
3.3v rails - These appear to be just cycling between 0v and 3v

I only got the PSU today, I wonder did they send me a bad one?

[tom66]

Re: Techwood 32HDMPEG4 IDTV

Definitely sounds bad to me, did the original do this too?

[JonathanAnon]

Re: Techwood 32HDMPEG4 IDTV

Just spotted there's a slight difference in the boards.. They are both 17PW25-3 070610, but there's a sticker on the board that is slightly different.. And on further analysis, there are no components on the new board along the line of the 3.3V rails... I'm gonna see if I can build that part of the circuit from the components on the old board..



The top rail does not exist on the new board..

[tom66]

Re: Techwood 32HDMPEG4 IDTV

You may find the transformer is different and you need to swap that too.

[JonathanAnon]

Re: Techwood 32HDMPEG4 IDTV

The transformers are the same, there just seems to be a few caps and diodes in different positions around the board, and that 3.3v rail doesnt exist.. Argggghhhh, I've made a mess of this one..



I saw that the board had a slightly different third number on the website, but they looked the same.. I guess that'll learn me for the future.. I'll have a think about it, but I'm blackballed, so I'll have to chance something..

[tom66]

Re: Techwood 32HDMPEG4 IDTV

You could return it...?

[JonathanAnon]

Re: Techwood 32HDMPEG4 IDTV

You could return it...?

Two problems with that Tom.. First I ordered three board to split the cost of the shipping here, so it would cost me a lot even to get it back. Secondly, they dont have the exact board, the only one I can locate so far is one in France for 70 euros, so at least if I keep the board I have the option of a) repairing board one with new one or b) building the bits on new board with old one.

The primary sides of the boards are essentially the same, so I'm gonna go through the primary side of the the blown board and see if I have all the blown bits on the new board.. I think this is probably the only feasible I have at this stage.. It'll be good practice for me anyway..