17PW26-3 Issue: Flashing Blue Light on TV

[vinceroger69]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

What voltage do you get across the large filter capacitor?

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

I assume ac? No voltage ac

The voltage is 400V dc and can be measured across C819

[speedypro]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

What voltage do you get across the large filter capacitor?

Nothing at all.

[speedypro]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Oh! DC? Across large cap I get 387vdc

[speedypro]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Have you got +400V

Got 235vdc

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

The 387V looks OK but you've said both 387V and 235V??

The 387V looks like the boost voltage which you need in order to have the secondary supplies.

[speedypro]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Yes, in pic I get 235vdc and across the large cap, C819, I get 387vdc

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

If you have 387V across C819 and the circuit is for your power supply then that's fine.

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

With the power supply disconnected from the main board what voltage do you have at the output connector when you switch on.

[vinceroger69]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Not sure why you have not got 12 or 24 volts though maybe budm has some ideas where to check next

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

It may be a fault in the secondary side

[speedypro]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Tough one. Oh, R1036 was damaged so I replaced with working and same issue.

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

The PFC is working so it may be a problem with the FAN7711/ Q813/Q814 which drive the primary of the transformer.
Have you checked all the diodes in the output stage. Q827, Q816, Q815, Q828, D881, D893

[vinceroger69]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

this is whats in the repair kit maybe check all these parts too

F800
Q813
Q814
IC830
D894
R860
R8661
R971
C840

[dick_barton]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

+1 They are the FAN7711 and components around it.

I would agree with vincerogers69 and suspect that this is where the fault lies.

[vinceroger69]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

with boards being this cheap though it maybe cheaper to buy this than buying ics etc
http://www.ebay.co.uk/itm/Power-Boar...0AAOSwAYtWKlXH
unless your like me and enjoy the challenge of fixing it

[speedypro]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Ok but how to test FAN7711 with a multimeter? Possible?

[vinceroger69]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Ok but how to test FAN7711 with a multimeter? Possible?

found this on another thread check between pin 6 and 8 for sc
A blinking LED in any other case than firmware update is mostly a power supply issue, but here's our checklist:

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).

[ReeceyBurger123]

Re: 17PW26-3 Issue: Flashing Blue Light on TV

Will reply tomoz busy tonight.