Baird X47DTV power supply issues

[gilly1984]

Re: Baird X47DTV power supply issues

Where can you buy the controller IC?

You can get the rest from Farnell, RS, etc.

Ic can be bought on ebay, but that cap is hard to find. Most are snap in, need one with lead legs.

Checked RS, Farnell and ebay to no avail.

[tom66]

Re: Baird X47DTV power supply issues

You could solder wires to the snap in terminals, and solder them to the board, then glue the cap to the board.

[budm]

Re: Baird X47DTV power supply issues

I do the same thing as Tom does.

[gilly1984]

Re: Baird X47DTV power supply issues

Cheers lads. I will do that. The whole thing will probs go bang anyway when i put all the parts in.

[tom66]

Re: Baird X47DTV power supply issues

Cheers lads. I will do that. The whole thing will probs go bang anyway when i put all the parts in.

Hah! Have some more faith in your repairs. I've only managed to blow up new parts once, and that was a stupid error on my part.

[gilly1984]

Re: Baird X47DTV power supply issues

Its what normally happens when i try and fix things.

Is that ic deffo the last thing that could of blown, or should i test anything around it?

Once i have all the parts and soldered them on, i can test everything against the other psu.

Does it need to be a hyperfast diode i use or can i use a normal diode?,, No better stick to originals.

I could do with a new ribbon too, all held together with wires and normal cellotape

[tom66]

Re: Baird X47DTV power supply issues

Get hold of a 100W lightbulb before you power it up, wire it in series with the suspect supply, if there is a short it will stay lit, otherwise it will go dim, and then you can attempt to wire it up directly.

[gilly1984]

Re: Baird X47DTV power supply issues

Got a psu from a 20 inch viewsonic.

the 24 volt is always on even when TV is off? would it be bad to try it in the Baird?

[tom66]

Re: Baird X47DTV power supply issues

Might mean the backlights are always on in standby.

I wouldn't trust a 20 inch power supply to provide 6 amps. A 32 inch one, maybe.

[gilly1984]

Re: Baird X47DTV power supply issues

Just took a closer look at this psu,

The parts i need are

1: pwm ic 1377b http://www.alldatasheet.com/datashee...377BD1R2G.html

2: P10NK80ZFP http://www.alldatasheet.com/datashee...10NK80ZFP.html

3: 8ETX06FP http://www.alldatasheet.com/datashee.../8ETX06FP.html

4: 450V 180UF CAP

The parts on this viewsonic psu are,

1: LD7575PS pwm ic and fp5001 ic http://www.alldatasheet.com/datashee.../LD7575PS.html

2: P8NK80ZFP http://www.alldatasheet.com/datashee...P8NK80ZFP.html

3: FMX26G http://www.alldatasheet.com/datashee.../FMX-G26S.html

4: 450V 82UF

Can i use these parts on the baird? I have had a look at the datasheets but it may aswell be in chinese to me.

Sorry for all the links, just saving you a bit of time.

Oh, and i ignored my own sig

[tom66]

Re: Baird X47DTV power supply issues

It doesn't look like you can use any of those.

[gilly1984]

Re: Baird X47DTV power supply issues

Thats a bummer.

Just tried this psu, and the lights start to flicker after a few seconds.

Oh well, buy the parts next week.

[gilly1984]

Re: Baird X47DTV power supply issues

Ok, my parts have arrived, all but the big cap that i cant afford to buy just yet.

I do however have a 450v 150uf cap i could borrow from another tv, would that do the job even though i need 180uf?

[tom66]

Re: Baird X47DTV power supply issues

What do you think? They cheaped out on everything else so they'll put in the minimum cap they can get away with. Low capacitance on PFC can cause the same damage you saw (PFC circuit goes "crazy" and pops other components) - if anything, the cap should be larger than it currently is. I suspect its failure killed the original PSU.

[gilly1984]

Re: Baird X47DTV power supply issues

You are right, the voltage is higher on this cap but this has slightly lower uf.

I will wait untill i get the correct cap. Just getting really excited to fix it, but there is no point rushing it i suppose.

Aswell as excited i am shitting myself in case it just goes bang lol.

This 1377b ic is bloody tiny, i will get everything soldered into its place later and show you my great smd soldering skills.

The vid you linked made it look so easy, i have been practicing on some small ic chips on freeview boxes and its definitely harder than how he makes it look in that vid.

Cheers Tom, If you didnt reply i probably would of just tried that cap like the idiot i am.

[gilly1984]

Re: Baird X47DTV power supply issues

Ok, as promised, here is my great smd work

Pic 1 is the power supply thats working, pic 2 is the one i am mending.

Pic 3 is a lifted trace on the 900v mosfet, looks bad but checks out ok for continuity.

I now have the same readings on both power supplies 1377b ic chips.

I cant put the hyperfast diode on yet because its attached to a heatsink that covers where the big cap goes, and without a solder sucker or braid there is no way i am going to attempt it.

I know it all looks crap but i have no sucker or braid, no shorts so far anyway.

[tom66]

Re: Baird X47DTV power supply issues

Looks OK, braid is cheap on ebay:
http://www.ebay.co.uk/itm/1-5mm-Sold...item231e705455

Fix that trace though with a piece of wire as sod's law will say it will break when you install it and then boom goes the MOSFET because the gate is floating and will trigger on any slight noise or leakage.

[gilly1984]

Re: Baird X47DTV power supply issues

The trace is connected, but i know what you mean, i will unsolder it and glue it down to the board, then resolder.

[gilly1984]

Re: Baird X47DTV power supply issues

Is RS open to the public? Phoned them and they said no, but spoke to their online assistant and they said its fine?

Don't want to go all the way there for them to say no.

Gonna order/collect the cap today.

[tom66]

Re: Baird X47DTV power supply issues

They have a trade counter usually £5-£10 minimum order.