bad capacitor

[davidvincent]

Re: bad capacitor

Yes just spoke to my friend and he's gone for the replace the caps option
best I think in the long run.

Again thanks for all the help and I hope this thread helps anyone else that has this power board

[ReeceyBurger123]

Re: bad capacitor

Nice great to here the set is working, replace the rest of the caps and enjoy your set

[davidvincent]

Re: bad capacitor

BINGO tv working perfect

It was the Samxon 100uf 25v Electrolytic cap it looked quite normal no bulging I went to Maplins and got an ordinary 100uf 35v cap and soldered in temp to test it must have been causing the buzzing on sound as well as that has now gone

So all Esr Saxmon caps need to be replaced

Thanks to everyone for steering me away from the 400 v cap

DV

[davidvincent]

Re: bad capacitor

Yes Agreed the low voltage side is full of them I changed 2 of the samxon start up caps they had blown their tops well on their way anyway.

I am going to change out the 100uf first and if I get the tv working ok I will give the option to my friend (its his tv) to do a full cap change to rubycon caps

[kc8adu]

Re: bad capacitor

just shotgun all those samxons.
that series/color are known bad.
nice to track it down to a single troublemaker but in the long term those all need replacement.

[davidvincent]

Re: bad capacitor

Hi after looking at it again and taking into account all that you guys have said I am now of the belief that the 400v cap is not at fault.

I have really isolated the 400v well using cardboard and plastic and blew warm air above it and the tv started to work, so above it is a diode (that is ok) and a ceramic cap so I put a tube on the ceramic cap and blew warm air the tv did not change.

So above the Ceramic cap there is another diode that seems ok. two small transistor's 1 big transistor TIP31C and 4 very suspect small electrolytic caps 3 @ 47uf 25v and 1 @100uf 25v I have put a tube over the caps I seem to get a reaction from the 100uf cap when I blow warm air on it I am now waiting for the tv to cool down and repeat the tests a few more times

BTW the electrolytic caps are samxon which are known to be pretty bad caps

At last I maybe getting somewhere

I will post again later with results

DV

[ReeceyBurger123]

Re: bad capacitor

ok I will get back once I have the replacement I will order one off ebay

thanks for your help

DV

Your welcome, keep us updated

[davidvincent]

Re: bad capacitor

ok I will get back once I have the replacement I will order one off ebay

thanks for your help

DV

[ReeceyBurger123]

Re: bad capacitor

Interesting, sounds like something els but replace the cap first to rule that out.

[davidvincent]

Re: bad capacitor

I just done another test on the cap
Cold no power ie not plugged in 0 volts
Plugged in not switched on 350 volts
Turned on screen flashing 340 volts
Use hairdryer on Cap until screen stops flashing (steady backlight) 325 volts

[davidvincent]

Re: bad capacitor

the cap goes down to nothing within a few mins when not plugged in

[davidvincent]

Re: bad capacitor

around 330 -340 volts at my latest test

[ReeceyBurger123]

Re: bad capacitor

I dont think its the cap what voltage does the cap measure when the set is on ?

[ReeceyBurger123]

Re: bad capacitor

Would this make any difference

I usally replace 150uf with 180uf on sets that are worth something it basically gives cleaner voltage to the switchers.

[davidvincent]

Re: bad capacitor

You can see the components near the Cap from this photo

[davidvincent]

Re: bad capacitor

I will upload a picture

[SteveNielsen]

Re: bad capacitor

What adjascent components may be heating up during the test?

[davidvincent]

Re: bad capacitor

Would this make any difference

[ReeceyBurger123]

Re: bad capacitor

Try replacing the cap with a higher value like 180uf 400-450v.

[davidvincent]

Re: bad capacitor

Hi thanks for your response

the cap looks fine, the psu is AD301M24-4N1

There is a thread on here were he had the same fault and heated the cap up and it worked he replaced the cap and it was the same, now like I posted I used some plastic and surrounded the cap and heated it up and bingo I had it on for 2 hours then switch it off for 5 mins and to get it back on you have to heat it up again

regards

David