non brandedset just says 32 lcd ut3219a

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

i have just re checked with second meter no ac voltage on outer 2 legs of bridge rectifier mains in on board has 244 volts ac.can you advise what to test next and how if needed cheers guys.

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

some more pictures that didnt attach this morning any ideas guys

[budm]

Re: non brandedset just says 32 lcd ut3219a

Please take the resistance readings:
1 & 2
2 & 3
4 & 5
5 & 6
They should have <1 Ohms readings.
The solder joints do not look very good.

[tom66]

Re: non brandedset just says 32 lcd ut3219a

My error: you need to check AC on the inside two pins, not the outside two.

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

thanks bud whilst you was looking at this for me i have done some more fault finding l818 is open circuit!! dont know how i missed it can you look at the scheme for me and see what i need to order from cpc i will take the readings for you and post in a few minutes yes the soldering on this board is rubbish it was in a deal on a tv i picked up just thought i would have a go a repairing a badly blown psu and to practice my fault finding and smd soldering we all have to learn somewhere i guess cheers budm / tom im sure once i replace this and tidy the soldering up all will be fine i hope.

[tom66]

Re: non brandedset just says 32 lcd ut3219a

As a quick test, since it is EMI reduction, you can just solder a jumper across it.

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

1@2 00.3
2@3 13.0
4@5 12.3
5@6 00.6
all tested on 200 ohms setting so i soldered a link across using my bulb tester to save parts with a 1k resistor across the pins tom advised before bulb flashed bright once went out tested all output voltages all spot on as per scheme so thats good now whats the part i need to order i will order some decent solder and remove and reapply fresh solder to the joints done by the previous repairer thanks again for your help guys.

[budm]

Re: non brandedset just says 32 lcd ut3219a

Can you cut open that L818 (Differential mode inductor) shrink tubing to what kind of damage it has? As you can see L816 has Thermistor in its place instead of another inductor, you can do without L818.

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

budm if i leave l818 out psu will not start run at all? not sure why as soon as i solder a link across alls fine? l818 has the top bit of wire blown apart 1mm gap i guess probs blown when the thermistor went which i have now replaced some of the readings you asked me to take seem high? tested with 2 different meters just in case are these readings ok? the scheme says its a 22u inductor i cant seem to find one at cpc or on ebay?

[budm]

Re: non brandedset just says 32 lcd ut3219a

You have to have jumper in place of L818 (when L818 is removed) because it is connected in series with other component to allow the current to flow all the way to the bridge rectifier.
I see TH1, TH2 so 2 & 3 (5 & 6) will be more than one Ohm due to the Thermistors in the ciruit.

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

cheers budm i have just re read what you have wrote so its ok to leave a jumper wire in place (ive used a capacitor lead cut off as a jumper link) so all will be fine now i guess i will re solder and claen up the board many thanks to you and tom for your helpive just realised ive forgot to change c833 capacitor http://cpc.farnell.com/avx/08055c104...0nf/dp/CA07634 as per toms advise ive done all the other bits though are these caps supposed to be fitted ie one side positve and one negitve or dont smd caps matter?

[tom66]

Re: non brandedset just says 32 lcd ut3219a

That particular cap has no polarity. You'll also notice there are no markings on it.

[vinceroger69]

Re: non brandedset just says 32 lcd ut3219a

cool cheers tom.