17MB25-3, blinking led

[papisco]

Hello every one, I have a Techwood model 32832, with a vestel board 17MB25-3, when the tv is powered up, the standby led comes on, and after few second it starts to blick, but the tv does not come on, nothing happens on the screen. I have looked at the PSU ,but no bulgy capacitors, I have also chechked the output voltages from the power supply, but thet are no atable, they keep on going up and down. Please can anyone help, ANY SUGESTIONS.
Thanks

[chappers]

Do you have all voltages present (3.3, 5, 12, 24)? Which ones are going up and down exactly?

Here are some solutions for this fault I have listed for this model and chassis:

• Check microfuse FS105 on main board, near CAM module.
• Check SMD fuse FS106 (4A) for open-circuit. Check diodes D881 and D893 (UF5402) for short-circuit.
• 24V rail might be short-circuit, disconnect inverter board supply to prove. Check and replace dual N-channel MOSFETs IC803 and IC804.
• Replace IC830 (FAN7711 and SMD capacitor C925 (1nF).
• Check for short-circuit between pin 6 and pin 8 of IC830 (FAN7711). Replace IC830 and SMD capacitor C833 (100nF).
• Check and replace SMD transistor Q839 (BC859).
• Check D893 and D891 (UF5402) in centre of PSU for short-circuit.
• Voltage at regulator U122 varies between 4V and 9V instead of being stable at 8V. Replace U122 (LM1117ADJ) on main board.
• Check C961 (470uF/35V) at top of PSU.
• Check D893 and R1036 (2.2K) on PSU.
• Replace IC830 (FAN7711).
• Check D893 and its feed resistor. Replace MOSFETs Q813 and Q814 and IC830. Replace C828.
• Replace C892 (100uF), C801 (33uF), C840 (33uF).

[WILLYAM1]

what is yourpwer supply?

[Turnip]

Hi Chappers,

Go along with Willyam as find nothing in my files or Quuq back threads on that Techwood 32832.  Thanks for the gen  - Chris.

[sparky]

hi
looks like 17pw20-1?
dave

[papisco]

Hi Chappers thank you very much, will check the power supply and see.

[papisco]

Hi Willyam the power supply is 17 PW26-3

[chappers]

The faults and cures list I printed earlier were for the Techwood 32832 using the 17MB25-3 main board and 17PW26-3 power supply.

Note that some components to be checked are on the main board, whilst others are on the PSU. If the info was available to me, then I've stated which board they're on.

[Turnip]

Hi Chappers,

Guess we're grateful for the info - no need to go into 'bold' - worrysome. Got the message, filed, and many thanks - Chris

[papisco]

Hi Chappres, thank you again. I changed the capacitors C802, C934, Q828, D882, D883 and some  capacitors, now the the TV IS UP AND RUNNING, though there is aporblem I am yet to fix, when the board where you have the power, volume and menu buttons is connected the screen will not come on, thevled will stay on for few seconds and go off and back on again and off.

[chappers]

Sod off Turnip, you patronising twerp. I added the message and the "worrysome" bold typeface because there was talk of which power supply was in the set, etc., after my initial message, so I thought I'd point out which main board and power supply my faults were listed for as my initial message didn't include the power supply I was making reference to - could have been a different one for all the OP knew. Thought it might help.

Is that okay?

Papisco, glad I could help. I'll try not to let the likes of Turnip put me off coming here and helping others. Sounds like you have a short-circuit on that board...

[Turnip]

Hi Chappers,

Sodded off - rarely patronising, but doubtless a twerp - go for it - OK - Chris