245BW, can't find problem. No 24 or 6.3V, standby is good.

[Toasty]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Good shot. I didn't find it because it is not in caps category. Thanks.
Hopefully I won't need it and the new RT852 will sort it out.

No. The problem is likely in the Zener's and possibly QT851. Lift that 24v jumper and see if 24v comes back.


<<Oh yes RT852 shows 168R>> ??
What does that mean? Its marking or the value you read with a meter?

Closest value I've at home is 1.4R 5W. Do you think it would be ok just for tests?

Tough to say. Don't know what its original value was.

@Toasty If he needed to replace the Long Blue cap could he use one of these?
http://www.ebay.co.uk/itm/PANASONIC-...=e100084.m1843

Yes, that should be fine.

T

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

I powered it uup with this large resistor I had. Unfortunately nothing changed.
I checked voltage on this large blue cap. Should it fluctuate from 300V to 330V-ish? Up and down all the time.
Same unstable voltage on QM802 as per pic attached.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

<<Oh yes RT852 shows 168R>> ??
What does that mean? Its marking or the value you read with a meter?




Tough to say. Don't know what its original value was.


T

Sorry I mean read value is 168R
Oryginal value of RM801 is 0.22R 1W.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

I lifted the jumper. Still cant see 24V.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

I will order and replace all four BZX84C22 and two LMBD2838LT1G.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

That was stupid what I've just done. I replaced blue cap with 100nF mkp and power resistor with 1.5R 5W one and powerd up. Resistor blow up loudly and two QM802 and QM802 are dead.

I go to sleep...

[Toasty]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Hmmmm.....

Could you have a bad mains cap?

T

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

I checked CX801S, CX802S and CP802S (circled). I only have multimeter with capacitance test. I read CX801S - 312nf, CX802S - 315nF and CP802S - 480nF. That look fine to me.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

I'm doing a shopping list. What else possibly could blown? I'm ordering some parts from Farnell so I can get everything in one go. I'll get the zeners, 100ohm smd resistor (RT852), mains caps, 22nF cap, 0.22ohm resistor. What else?

[Toasty]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

With no load and it blew, I'd be looking carefully at prior work.

In the future, use the "lamp-in-series" trick to prevent these types of surprises:

https://www.badcaps.net/forum/showpo...2&postcount=23

Make sure to use a real incandescent lamp, not any other type (no CFL or LED).

-----

Don't need those white caps. I re-read your list, and now with the pics, I saw you already replaced the mains cap with a KXG.

Assume you have the missing heatsink. ( Why is it off? )

What zener values did you choose? DZT852 and...? (just to be sure)
How did you determine?

Order more than 1 of the 100Ω. Usually a strip of 5 or 10 is minimum...?

Same with the 0.22Ω a couple-three won't hurt.

Check QT851. ( 1P type )

Both FETs, correct? Did you do ~exact~ replacements in the first go or subs?

Double check RB801S, the other power resistor.


T

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Yes I read about lamp trick, I'll try it. The heatsink is missing because 24V jumper I lifted was underneath.
I am away from my pc so I don't know the zener values but I've got schematic and I go by it.
Every part I order now is always more than I need so I have a spare.
First FETs I ordered were exacly the same but now I'm thinking to get replacement as per Fairchild Semicon the original are not being made.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Hello
I finally received all replacement parts. I also used the lamp in series trick. Looks like it saved me a lots of trouble.
When I switch power on bulb comes on then after 2-3 seconds starts pulsing at almost full brightness. When I touch on/off button led comes down as well as the bulb. Stand-by is working, that for sure
I've no idea what's wrong. Could it be MC33067 (ICM801)?

[budm]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Did you check that red rectangular cap next the 24V transformer? I believe it is 18nF 630V it is one of the commonly fail cap, verify that it is still 0.18uF.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Yes. It's brand new and it's 22nF 630V.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Ok that's weird one. When I let it cool down for a few minutes, after first power up the bulb comes on, then power off and on and the bulb only flash once and stays off and I have the 24V!
Unfortunately only until next power off/on. Then the bulb comes and stays on until I let the system cool down again.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Then the bulb comes on and pulsing the 24V slowly coming down, 1V every 2s.

[selldoor]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Whilst you are saying what you are seeing I am not so it would help if you could
differentiate between bulbs? May be just me

That is please say "Dim Light test Bulb" "Power led" or "ccfl" as against "bulb"

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

I had 24V jumper lifted. When I soldered it back on the 24V gone. Now I need to switch off/on many times more to get the bulb come off, and event then I have no 24V.

[Yaaman]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

When I say the bulb i refer to "in series bulb trick" bulb. Inverter is not even connected so I didn't mean ccfl. LED is the led on the front panel.

[selldoor]

Re: 245BW, can't find problem. No 24 or 6.3V, standby is good.

Have you tried with the ccfls connected - with them not connected may shut down as
being faulty?