technika 42 lcd 910 power probs

[exmortis]

Re: technika 42 lcd 910 power probs

You need to use low-esr capacitors. Farnell sell them as do RS. Capacitors from the average shop can cause lots of issues. Good capacitors to use are Panasonic FC, FM or FR.

ok i have some others now good ones i try them instead now and keep ya posted many thanks

[tom66]

Re: technika 42 lcd 910 power probs

Which ones do you have? Brand and series? Seriously, most capacitors are NOT suitable.

[exmortis]

Re: technika 42 lcd 910 power probs

Which ones do you have? Brand and series? Seriously, most capacitors are NOT suitable.

they where capcon ones same as removed , tv does the same , and i checked the 24v to the invertor and they do get a feed briefly then the tv clicks back off and the voltage drops off.

[tom66]

Re: technika 42 lcd 910 power probs

Capxon are really poor capacitors.... I've replaced more of them than any other...

[exmortis]

Re: technika 42 lcd 910 power probs

Capxon are really poor capacitors.... I've replaced more of them than any other...

ok if i sort them what would be the next step to test ? iam stuck now on what to check.

[exmortis]

Re: technika 42 lcd 910 power probs

ok if i sort them what would be the next step to test ? iam stuck now on what to check.

what about Rubycon capacitors ?

[tom66]

Re: technika 42 lcd 910 power probs

They are very good, but you can get a lot of fakes if you buy from shady shops, let us know the series (e.g. ZLH, YXF, MCZ) before replacing them as we need to know if they are low esr (not all Rubycon caps are.)

[exmortis]

Re: technika 42 lcd 910 power probs

They are very good, but you can get a lot of fakes if you buy from shady shops, let us know the series (e.g. ZLH, YXF, MCZ) before replacing them as we need to know if they are low esr (not all Rubycon caps are.)

they are MCZ are the series anygood

[exmortis]

Re: technika 42 lcd 910 power probs

would increasing the microfarad on the replacements cause a issue i.e going from 470 to 1500 same voltage tho ?

[tom66]

Re: technika 42 lcd 910 power probs

Yes, almost certainly. And, MCZ are not suitable for TV PSU.

[exmortis]

Re: technika 42 lcd 910 power probs

Yes, almost certainly. And, MCZ are not suitable for TV PSU.

what next thing i can test once the caps are sorted ?

[tom66]

Re: technika 42 lcd 910 power probs

We can check the output rails and main board.

[exmortis]

Re: technika 42 lcd 910 power probs

We can check the output rails and main board.

ok i been testing and checking components , i found a 4.7Mohm resister open circult which i replaced has resolved the buzzing issues from power supply, still remains in standby, i just been testing Mosfets on invertor and found n channel bottom 4 are at fault model fdd8447l 40v , iam right in saying they operate similar to diodes back to back and only allow current one way through ?

[vinceroger69]

Re: technika 42 lcd 910 power probs

http://howtoblogpost.blogspot.co.uk/...st-mosfet.html

[tom66]

Re: technika 42 lcd 910 power probs

That is stolen verbatim from 4QD.
http://www.4qd.co.uk/serv/MOSFETfail.html
http://www.4qdtec.com/mostest.html

[exmortis]

Re: technika 42 lcd 910 power probs

That is stolen verbatim from 4QD.
http://www.4qd.co.uk/serv/MOSFETfail.html
http://www.4qdtec.com/mostest.html

yeah i think the 4 mosfets on the invertor next to the 2 caps are knackered i have to get some and change them and see what happens

[vinceroger69]

Re: technika 42 lcd 910 power probs

That is stolen verbatim from 4QD.
http://www.4qd.co.uk/serv/MOSFETfail.html
http://www.4qdtec.com/mostest.html

sure is stolen a good testing guide though tom can these be tested in circuit or have to lift the fets legs? i am never sure

[tom66]

Re: technika 42 lcd 910 power probs

In circuit is usually OK, once a suspicious device is located, remove it from the circuit and test out of circuit.

[exmortis]

Re: technika 42 lcd 910 power probs

In circuit is usually OK, once a suspicious device is located, remove it from the circuit and test out of circuit.

anyone got 4x FDD8447l mosfets they can send us in the post, cant get any at the mo

[tom66]

Re: technika 42 lcd 910 power probs

*cough*
http://www.ebay.co.uk/sch/i.html?_tr...at=0&_from=R40