DIGITREX CTF3271 PSU bsfp3220004ad

[is_it_a_bird]

Hi

I am normally a reader not a writer, so hello to everyone in what looks like the most informed site on the net for repairing TV's

The problem I am having is with bsfp3220004ad, and I cannot find anything on it, no schema no other people with the fault and this is the 2nd one in a week I have come across.

The symptoms are dead, no standby.

The first one I came across was fuse destroyed and fets s/c'd, I replaced the fets and checked everything and still couldnt get no life from it, so I just got another board

The second one is a little strange, fuses all intact, but one of the fets destroyed other one s/c'd...see attached pic, I replaced the fets 8n60 and still nothing, again all the other components check out fine, I have done all the school boy errors that catch you out ie switch o/c, 240v is getting to the board and primary seems fine.
To be honest with this board I think someone has been playing engineer and proding probes everywhere with the power on and shorted the fets (tv had half the screws missing out the back)

Has anyone else come across this board and any problems or pointers as I am at a loss with it, I believe you can interchange these boards with one of the mlt range, think its 666 or 668 off the top of my head. So all is not lost if its better to scrap and replace.

Thanks for any help, the replies may be a bit scarce as I have been ordered to lay the laminate today :o(

Thanks in advance for any help

[selldoor]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

I suppose the first decision would be to work only on one board, then if that cant be fixed start on the other. You can work away on both but it will get very confusing if we try and look at two at the same time as they may have different faults.
Pics need to bea little better for troubleshooting
Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

When you replaced the mosfets and the fuses did it switch on ok or blow again?
You say primary seems ok so have you measured the DC on the main cap

[vinceroger69]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

is there any components on the underside of the board?

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

I suppose the first decision would be to work only on one board, then if that cant be fixed start on the other. You can work away on both but it will get very confusing if we try and look at two at the same time as they may have different faults.
Pics need to bea little better for troubleshooting

Sorry I should of been a little clearer, I am not working on the other board or comparing with the one I am working on else like you mentioned it gets messy, the first board is trashed and in the pile ready for me to nick decent bits I need in future.

The second board (pictured..which I will update later for clearer images) this is the board the pictured fet came off....no fuses were blown, which did surprise me a little looking at the state of that fet and the other being s/c'd

When you replaced the mosfets and the fuses did it switch on ok or blow again?
You say primary seems ok so have you measured the DC on the main cap

Like mentioned the fuses in this board were intact, and no the fets havent blown again they are still fine.

Smoothing has 322v across it.

No 24v
No 12v
all 5v pins I am getting between 1.9-2.5v

Will try and get better pics shortly

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

is there any components on the underside of the board?

Will take pics of underside too

[selldoor]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Smoothing has 322v across it.

No 24v
No 12v
all 5v pins I am getting between 1.9-2.5v

is that with just this board connected to mains or with it all connected up

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

is that with just this board connected to mains or with it all connected up

All connected up

[selldoor]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Are the pins on the connector labelled (back or front)

The 5 small caps on the primary side - one is likely to be the startup cap 25v or50v can you test the voltage across it.
Jumper4? near the big cap and the heatsink is it just a wire with a ferrite tube or is it something else?

When you do more pictures can you post topa nd bottom of the main board and inverter board

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Hi sorry for the late reply.

The story so far, I have tried taking better pics but my camera is rubbish, and my shakey hands dont help,

J4 Yes just a jumper wire

Connector is labelled both sides, I have attached the best picture I can with all the voltages across the 5 caps you mentioned

Thanks in advance

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Anyone???

[ben7]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Q7 should be on a heatsink! I would check that first, and then check the voltages at the output voltage connector.

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Hi

Q7 is no longer attached to a heatsink they removed it on a revision as I have seen the earlier board...(which normally takes the bridge out), Q7 is fine no problems.

Without trying to confuse the post I have just had another TV with this board in, same fault, fuse blown and fets S/C'd, replaced them and I am now getting 4.6v from the 5v side and the TV is now showing a green led just no 12 or 24v, think it may be better to get this board running and use it to cross refer to the first board

The output connector is as follows

Pins 1 & 2 = Gnd
Pins 3 & 4 = 5v
Pins 5 & 6 = PS & 5vsb
Pins 7 & 8 = 5v
Pins 9, 10 & 11 = Gnd
Pins 12 & 13 =
other block connectors are 12v and 24v

Is it possible to remove the connectors and short a couple of the pins out to kick start the 12 & 24v
I have done it before using the 5v to on/off pin but not sure which one on this board to short..if any

Thanks in advance

[selldoor]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

You keep giving us just half the information - remember we cannot see what you are doing. Can you get someone else to take the pictures or set up the board and the camera and use the shutter time delay?
Please list the cap values against the voltages you put on the picture.
Please use the list you have above for the connector but give us each voltage at each pin.
Need to test/list 3 times. First when its plugged in second when its switched on and third as its switched on ( No need to test the ground pins )
The PS/5V is probably the pson and perhaps the third test will confirm.

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Ok will get on with that now and try again with the pictures

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Right here you go

Standby Voltages

P3/5v = 4.73v
P4/5v = 4.73v
P5/PS = 0.00v
P6/5VSB = 5v
P7/5v = 4.72v
P8/5v = 4.73v
P12/13/12v = 0v

"On" Voltages

P3/5v = 4.54v
P4/5v = 4.54v
P5/PS = 4.42v
P6/5VSB = 5v
P7/5v = 4.55v
P8/5v = 4.55v
P12/13/12v = 0v

"Start Up" Voltages

P3/5v = 4.54v...this did drop to 2.54v when starting but 2nd test showed no drop
P4/5v = 4.54v
P5/PS = 4.42v
P6/5VSB = 5v
P7/5v = 4.55v
P8/5v = 4.55v
P12/13/12v = 0v

I have attached clearer pictures too

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Ooops sorry missed some info

The cap ratings are as follows
c18 = 1nf x 50v
c19 = 22nf x 50v

c21 = 22nf x 50v
c27 = 22nf x 50v
c28 = 1nf x 50v

[selldoor]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Great pictures - perhaps try to get some of the main Board?

What are the part numbers on IC1 ( Looks a bit heated?) and the similar device across to the right

Cant see any fuses to check other than the main which is obviously ok, can you

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Will post main board pics in 2 minutes, ironically the phone is much better than my camera at taking pictures

IC1 = ob6563cp

Cannot read the number on the other ic :o( will check on the other boards if any better

I did disconnect all the connectors and shorted out ps with 5v but still got nothing from the 12 and 24

I cant see any other fuses

[is_it_a_bird]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Here are the images of the main board and the other icc is ez949

[selldoor]

Re: DIGITREX CTF3271 PSU bsfp3220004ad

Will look at them in a minute or so - It could be that as there is a voltage on all the pins it needs to be pulled low to turn on? I dont know a lot about Tvs
I have just seen others do that recently. They take a 200 ohms resistor and short the pin to ground which then switches on the other other voltages.
Perhaps if Tom66 comes on later he will advise unless you know that trick?
I see there are traces from the 12 and 24 v to some small components ZSx
- perhaps need to check them out some time wonder if they are some sort of zener diodes?