Sceptre X405BV-FHD3HF02205 no power

[bodh]

Re: Sceptre X405BV-FHD3HF02205 no power

For anyone else that finds this and has the same issue, digikey was able to recommend a sr5200 schottky rectifier diode. It appears to have fixed the issue, as the tv is functional again, and the material cost was about $.64.

[bodh]

Re: Sceptre X405BV-FHD3HF02205 no power

Thank You budm. Can I ask how you've learned so much? You an electronics tech or something? I don't know how you knew to go right to the big filter capacitor and work from there!

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

Mouser does not stock MBR5200 either.
You can contact DIGIKEY or Mouser to get the sub for it.

[bodh]

Re: Sceptre X405BV-FHD3HF02205 no power

MBR5200 OEC(manufacturer's symbol?) 2159. It looks to be a Schottky rectifier diode with a 200v and 5a rating.. I found 10 packs to be expected mid-march as an offshore option, just not sure if i could source a compatible item sooner.

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

Did you find a source for this diode? I'm repairing the same board, tv's model is only different at the end by 04 instead of 05. I ran through these tests and sure enough that same component is ringing as bad. Removed it and i have my 5vsb.. I'm looking at replacing it with an mbr5200 in a DO-27 style instead of the DO-27(B), since that appears to be all that is available.. They appear to have the same ratings, but i know little about electronic component markings..

What is printed on the shorted out diode?

[bodh]

Re: Sceptre X405BV-FHD3HF02205 no power

Did you find a source for this diode? I'm repairing the same board, tv's model is only different at the end by 04 instead of 05. I ran through these tests and sure enough that same component is ringing as bad. Removed it and i have my 5vsb.. I'm looking at replacing it with an mbr5200 in a DO-27 style instead of the DO-27(B), since that appears to be all that is available.. They appear to have the same ratings, but i know little about electronic component markings..

[dnixon]

Re: Sceptre X405BV-FHD3HF02205 no power

Any suggestions on quality brands and where to get them?

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

You are good then, just replace that shorted out diode.

[dnixon]

Re: Sceptre X405BV-FHD3HF02205 no power

5.25 vdc on +5vsb pin

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

Removed D10 and retested:

DMM diode test - 0v forward and back
DMM ohms - 0 ohms forward and back

OK, you can leave D10 out for now, you can then apply an AC to the power supply board by itself without other boards connected, you should then see 5V at +5VSB pin of the connector CON 2.

[vinceroger69]

Re: Sceptre X405BV-FHD3HF02205 no power

yes thats bad so you will need to obtain a new one. budm mayhave some more tests you can do just to rule out any more blown parts so wait for now until budm sees this post and then you can order the parts you need etc.

[dnixon]

Re: Sceptre X405BV-FHD3HF02205 no power

Removed D10 and retested:

DMM diode test - 0v forward and back
DMM ohms - 0 ohms forward and back

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

d10 looks like it might be shorted you may have to remove it and re test

+1

[vinceroger69]

Re: Sceptre X405BV-FHD3HF02205 no power

D10 looks like it might be shorted you may have to remove it and re test

[dnixon]

Re: Sceptre X405BV-FHD3HF02205 no power

I tested the diodes 3 ways:

1) DMM in diode test mode

D10 - Forward 0v Backward 0v

D22 - Forward 0.16v Backward 0.9v

D23 - Forward 0.16v Backward 0.9v

D22 - This is a 3 terminal diode. I am calling the terminals 1, 2, and 3
where 2 is the middle terminal. I am assuming 2 is a common negative.

1,2 Forward .22v Backward first showed 0.9 then went to 0
3,2 Forward .22 v Backward first showed 0.9 then went to 0

1) DMM in ohms

D10 - Forward 0 Backward 0

D22 - Forward 0.86 Backward varies

D23 - Forward 0.88 Backward varies

D22 -

1,2 Forward 1.5k Backward 0
3,2 Forward 1.5k Backward varies

1) analog in ohmsx1

D10 - Forward 6 Backward 6

D22 - Forward 140 Backward 10

D23 - Forward 140 Backward 10

D22 -

1,2 Forward 500 Backward 10
3,2 Forward 500 Backward 10

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

OK, it is the same board.
You need to do resistance test on the Diodes D10, D21 (mounted on the heatsink), D22, and D23 to see if any of them show low resistance in both directions.

[dnixon]

Re: Sceptre X405BV-FHD3HF02205 no power

I have attached another picture of the front of the board and added one of the back. I thought that might be easier than trying to tell if my board is exactly the same as the post #6 picture. If this won't work i'll try to compare the board with the pictures. Also, I see that the size shown in the post for the pictures is much smaller than what I see on my hd. So I assume they are compressed wen uploaded. Does this mean I could attach a higher resolution picture?

[budm]

Re: Sceptre X405BV-FHD3HF02205 no power

I have about 170 vdc on the cap

OK, good, now we need to find out if this Voltage is fed all the way to the STBY SMPS section or not, I will need to trace the connection from the + leg of the main filter cap and see if there is a fuse or fusible resistor on the way to the pin of the STBY power transformer or not, that is why I NEED to know if your board is an exact match as in post #6.

[dnixon]

Re: Sceptre X405BV-FHD3HF02205 no power

I have about 170 vdc on the cap

[dcapper]

Re: Sceptre X405BV-FHD3HF02205 no power

The shrink wrap doesn't have to go back on. Don't worry about that. Like budm said be very careful when the tv is on. The power board can pack a punch. And make sure you don't short out anything while metering.