Philips 42FD9954/17s dead

[ryan74]

this plasma does nothing. no led(standby), no relay click. no response at all.
caps visually look good, 120v at main fuse
I cannot find a service manual.
I would apreciate some help and a service manual if possible.
the main fuse tests 120vac but it is labeled 250v.

Philips model# 42FD9954/17s

I can supply closeup pics if needed.

[ryan74]

Re: Philips 42FD9954/17s dead

here are close up pics of, only the left side of board.

[tom66]

Re: Philips 42FD9954/17s dead

This is an Hitachi plasma panel.

I am picking up a 37PF9975 tomorrow (with sienoki), it should be very similar. The one I am picking up will power on and work fine, just shuts down after some time -- hopefully cold joint somewhere.

So I might be able to offer some test points, if it is sufficiently similar.

[ryan74]

Re: Philips 42FD9954/17s dead

thanks ill be waiting.
my panel sticker is:
Fujitsu Hitachi
FPF42C128128UB-72
#N7A304224F103A

[tom66]

Re: Philips 42FD9954/17s dead

The manual is available on a paysite that a member here has access to. I have asked him kindly to provide it so I can host it for free. I cannot find a manual for the 37PF9975 anywhere though.

Also, early Hitachi-Fujitsu plasma panel. Interesting. 90V sustain design (vs 180-220V for conventional Panasonic/LG/Samsung tech), ALiS technology, 1024x1024 resolution (interlaced...) Rather strange design -- but Fujitsu jumped out of the boat, and left Hitachi with the technology. Hitachi didn't last, sold their stuff to Panasonic I believe. Shame, as plasma is starting to make a bit of a comeback. Most people expected it to die.

[tom66]

Re: Philips 42FD9954/17s dead

Manual:
http://www.tgohome.com/ServiceManual...&Search=Submit

[ryan74]

Re: Philips 42FD9954/17s dead

Thank you.
Please thank the member for me also.

[tom66]

Re: Philips 42FD9954/17s dead

You can thank Mr Bill yourself He kindly provided the manual from a pay site he has access to.

[ryan74]

Re: Philips 42FD9954/17s dead

doing a quik search I found this.

http://www.tv.quuq.org/forum/index.php?topic=2550.0

I havent looked at the pdf yet.

[ryan74]

Re: Philips 42FD9954/17s dead

Thanks for the manual Mr Bill!

After turning power on, the red led does come on after about 1 minute.
If I turn it off and on again red led comes on right away.
If I let it sit off a while and turn it on I have to wait a minute for red led.
no blinking led

I tested con 0320
1) empty
2) green led
3) red led
4) RC_in
5) light_sensor_in
6) +BV6
7) G
8) +5v_STBY_SW
9) +9v_STBY_SW
10) +9v_STBY

My readings
1) empty
2) 3.29vdc
3) 0.0v
4) 3.53vdc
5) 0.0v
6) 0.0v
7) G
8) 5vdc
9) 6.86vdc
10) 6.86vdc

9v standby is low

[tom66]

Re: Philips 42FD9954/17s dead

Replace the standby startup cap, that would be my suspect if it takes ~1min to power into standby.

[ryan74]

Re: Philips 42FD9954/17s dead

as soon as i turned it on i checked voltage at cap2541 and had 2.72v.
once red led came on I rechecked cap2541 and had 5.03v.

Is there an easy way to identify the startup cap or do i have to find it in diagrams?
I have trouble reading diagrams and theres alot.

[tom66]

Re: Philips 42FD9954/17s dead

My error. This design doesn't use a startup cap. TNY256 doesn't need it.
You need to trace where the 9V is coming from. I don't think that small transformer is the source but I could be wrong.

[tom66]

Re: Philips 42FD9954/17s dead

It's a small one on the primary side.

This should be a good start (you want the "Wiring Diagram")
http://tgohome.com/ServiceManuals/?d...&Search=Submit

All results for similar model:
http://tgohome.com/ServiceManuals/?d...sd1e&typekey=0

[ryan74]

Re: Philips 42FD9954/17s dead

I found tny256(loc7500) control.
It looks like there should be 400v going into control/standby supply from preconditioner.
I will look into it more tomorrow.

[ryan74]

Re: Philips 42FD9954/17s dead

I let this stay pluged in an hour with power switch on(red led) then i grabbed remote and hit power and relay started clicking about 6 times and led turned flashing green durring clicking. i got no response from remote when i first powered it on. I still just get red led when i push power button

I took what voltage measurments i could from top of board and marked them on pic.
at 3506 I tested 170vdc but schem. shows 500v(400v from preconditioner)
I need a little help here.
I dont know what the preconditioner is.
If TNY256(loc7500) and CE165T(loc5500) should be fed 400-500v as schematic shows should I look at preconditioner?

or
Is this voltage ok and do i need to test CE165T and TNY256 for faults.

i also found this:
To make it short, i replaced most of the electrolytic caps and mylar
caps in the Preconditioner stage and VsVa Power supply stage. And
finally the PWM Oscillator IC (MC34067P).

You have to make sure that the Preconditioner stage is running ok,
with an output of 380 to 395 volts DC. There are two fuses on the
board (in my 32FD9954), one is for the mains AC located near the mains
connector coming from RF filter (two wire connector- large wires), the
other fuse is in the middle of the board. You measure the DC voltage
on this fuse on the middle of the board and it should be about
380volts or above.

The real culprit is the PWM IC. Initially i replaced the MOSFET
(STY34NB50F) in the Preconditioner, then the caps, then finally the
IC. Then it worked!!! Just replace the electrolytics near the PWM IC
(2.2u, 4.7u, 100u, a couple of 1000u)

I think the design problem is that the IC is nearly located to the
heatsink which generates lots of heat. The IC deteriorated in time and
the electrolytes in the capacitor evaporated due to the excessive heat
inside the case. I'm thinking of incorporating 120cm computer fans at
the back to suck down the heat.

http://cgi.ebay.com/ws/eBayISAPI.dll...MakeTrack=true

[ryan74]

Re: Philips 42FD9954/17s dead

I may just replace the board unless someone can say for sure what my problem is or give more advice. I hate to buy the kit for $30 and still not have it working.

http://www.shopjimmy.com/philips-312...upply-unit.htm

[rayrod81]

Re: Philips 42FD9954/17s dead

I have seen a couple of these and the TNY265 IC was a problem on both. On one of them I replaced most of the caps, the MC34xxx chip(I can't remember the exact one as I believe there are 2 on the 42" PS), and the TNY256 and it still was not working. What I found was that there was a problem with the varistor where you are seeing the 170V. You will have to pull it out of circuit to test but if the resistance is low then it is bad. It should read very high resistance if not infinite.

[ryan74]

Re: Philips 42FD9954/17s dead

I pulled and checked all 3 varistors with dmm on autorange.
loc3506= 10.7ohm
loc3450= 10.7ohm
loc3451= 9.2ohm
I read under 100ohm is bad.

I want to make sure i understand this right.
The preconditioner should send 400v to stby supply just when plugged into wall?

[tom66]

Re: Philips 42FD9954/17s dead

It doesn't run in standby.