bush led24970dvdfhd (vestel_17mb62-1) flashing red led

[LastMinuteMan]

Hi, I've bought this tv to repair and hoping for a little help. When I bought the tv the owner said it just goes into standby. When I got home and tried turning it on I got the flashing light no pattern just flashes steadily.

The owner as now told me they had it looked at and said they was told it needs a new mainboard (vestel_17mb62-1)...

Anyways I checked tp202 on the mainboard and it is reading 0v and from the manual it seems it should be reading 3.3v to be good. I have checked the voltages going into to mainboard from CN1 and they read as follows

Pins 1 to 8 read 0v

9. 4.88-4.92 was fluctuating
10. 11.25
11. 0.69v
12. 0.69
13. 11.25v
14. 11.25
15. 3.4v
16. 0.69
17. 3.4v
18. 0.69
19. 3.4v
20. 0.69

Test was done with mainboard attached. I also probed U175 (UTC ld1117al) adjustable voltage reg see attached pic, the first pin furthest away from the cap that sits next to reg reads 0v as does the second and the third reads 0.69v??

What should my next step be?

Thanks in advance

[selldoor]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Next step is to get some better pictures - more light required but not flash then we can see what your talking about.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Put some better pics up. Thanks

[tom66]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

I've had this fault caused by a shorted CPU, however in my case the TV was completely dead (no power light at all.) Test the output for shorts to ground. Mine was about 5 ohms to ground, dead CPU. Tried pulling everything and it made no difference. If there are no shorts, I would try replacing the regulator.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

I've had this fault caused by a shorted CPU, however in my case the TV was completely dead (no power light at all.) Test the output for shorts to ground. Mine was about 5 ohms to ground, dead CPU. Tried pulling everything and it made no difference. If there are no shorts, I would try replacing the regulator.

Pin one, on the mainboard (soft_sw) reads 0 ohms to ground. The rest check ok. I'm guessing that's not normal?

[tom66]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

That pin is for an optional "low power standby" which turns off the standby power to the main board. A simple switch is used so it can be turned on without standby power. 0 ohms is normal. I don't think I have ever seen it used.
You should check the regulator for shorts...

[selldoor]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Tested the small fuses with a "w" on
Id guess they are good but see a fuse - test it.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Thanks for your help, I will try changing out the voltage reg and report back with the good or bad news lol.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Tested the small fuses with a "w" on
Id guess they are good but see a fuse - test it.

Yep already done that all test good. Thanks

Just had a look at the v.reg and the pin that measured 0.69v is Vin...So I presume the problem is before the reg?

Just checked pin to pin ohms to ground on the reg. Pin1 (ground). 0.97ohms Pin2 (Vout) 197ohms Pin3 Vin 506ohms?

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Well the V.reg seems to be ok. I'm thinking about buying a replacement board but before I do, does anyone know if I can use a 17MB62-1 v2 in place of my 17MB62-1 v1?

The boards look identical. Thanks

[tom66]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Only if they both go in a Full HD panel made by the same manufacturer. i.e. Samsung -> Samsung.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Only if they both go in a Full HD panel made by the same manufacturer. i.e. Samsung -> Samsung.

Ah that's a shame, the board I'm looking at came from an Hitachi. Thanks for the quick reply.

[tom66]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

No, I mean the panel, not the manufacturer. It would be OK if that TV uses a Samsung FHD panel for example.

[selldoor]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

I am not sure that is clear - I think he is saying the panel manufacturer must be the same as against the TV set manufacturer.

IF your TV has a samsung panel then the new main board must be from a set with a Samsung panel.
If your set has a CHI Mei Panel then the new board would have to come from a set that had a ChiMei panel.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

well my panel is led and the board on ebay was used with an lcd so probably not any good to me. Looks like I'm stuck with it at minute lol. Seen one that matches but the guy wants 50 quid for it :/...

[tom66]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Maybe make the guy an offer - he might rather have £25 than nothing...

[selldoor]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

I have been looking again at U175 - If I read the schematic right which is unlikely
the pin nearest the C1080 is the 5v Vin and the black component is F303 ???60R???
Is that a fuse? then or a Ferrite bead?? or fusible resistor??? either way it may be worth checking it. Maybe also check the voltage on that C1080

[tom66]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Ferrite bead - 60 ohm impedance (NOTE: not the same as 60 ohm resistance, on a meter will test as short circuit.)

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

I have been looking again at U175 - If I read the schematic right which is unlikely
the pin nearest the C1080 is the 5v Vin and the black component is F303 ???60R???
Is that a fuse? then or a Ferrite bead?? or fusible resistor??? either way it may be worth checking it. Maybe also check the voltage on that C1080

I checked the voltage on the cap and reads 0.69. I have also tried removing the cap and the pad reads the same.

[LastMinuteMan]

Re: bush led24970dvdfhd (vestel_17mb62-1) flashing red led

Does anyone know how I could disable the short circuit protection on this board?