Search for plasma TV power supply schematic Pioneer PDP-427XD

Hello,

You can still read this https://www.depanntout.com/login.php?redirect=p49390.htm#p49390

There must be an identification plate glued or engraved on the card or circuit board... Brand and model.. could you take a clear photo

the diagram would only be the power supply block if a diagram exists.. (the Russians)

I can't find exactly your power supply, apparently it's no longer available... and the schematic... I can't find it either

here's what I found for example. https://www.eserviceinfo.com/download_start.php?downloadurlid=44448

it seems to be based on a SANKEN brand, this power supply is used on several TV brands

Yours must already be a bit old..?? to repair it without a schematic, it's a bit like poker... but you can search or replace the capacitors, look closely at resistors that might be burnt... or fuses.. did you have 350 volts behind the rectifier bridge..? monitor all the places that heated up (dark brown) possibly redo the soldering, the temperature can melt the solder and create a "dry" solder joint ..
Are you sure it's the power supply that is faulty..?? an overload downstream can bring it to its knees.

Thank you very much for your help.
No storm expected... but it’s possible...
We can see on page 49 of the manual that the relay is controlled by another board which must indeed incorporate the error detection to authorize or not the powering of the main part of the power supply, whereas this other board is powered elsewhere, by a circuit on the power supply board, that’s what I’m looking for.
The YouTube video is actually a seller of used parts.
But at the moment there are none in stock.
I’ll do the repair as soon as possible by powering it with the lamp in series...
See you later

I would be delighted with the diagram of this card, but I don’t have any comrade...

In response to your initial remark, not only is it no longer done, but Pioneer Television no longer exists; after-sales service (SAV) now handles car radios, amplifiers and home cinema: I wrote to Marseille, their reply: they don’t do it and they don’t know.
It’s no longer obsolescence but a pure and simple disappearance of the company’s branch!

Actually, I’ve already done a bit of digging on the circuit board and I have a lead:
there is a relay that must latch to deliver current to the main diode bridge and big capacitors: it doesn’t latch, so I have nothing anywhere. I’ve desoldered the big capacitors and they’re good.
The problem is probably upstream in a standby/error-monitoring circuit that latches or unlatches the relay.
There is a voltage divider (right after the mains input connector, the fuse and the filtering capacitors) of two 4.7 ohm 5W resistors, one of which is a fusible resistor that hasn’t melted; it’s the other, the plain wound ceramic one, that’s open.
It’s the start of a small switch-mode power supply. However, in this two-sided board with metallized through-holes where the current wanders from one face to the other, it’s very hard to follow because components hide the tracks on the top.
I can clearly see a diode and a capacitor; it might be a zener, but I don’t have much information.
I’d like to avoid replacing the power resistor without checking downstream to avoid burning it again…
There you go.
Thanks for the manual, but there’s no schematic and the component values are “coded”—it’s insane…
But if the schematic is unobtainable, I may still try anyway.
I’ll wait a bit (I ordered the resistor, well 5 of them, from Farnell for 14 pence each) and while I have the part on order perhaps someone will have an idea…
What are the Russians?

cordially,
good evening

Russians, it’s a site that had all the schematics ... named Schematic... it doesn’t respond anymore

Here’s a video that looks like your case

So the 220 doesn’t even reach the rectifier...?

And this relay that cuts the line, it’s almost certainly a safety... It doesn’t latch because not all startup conditions are met... at least one is missing..

Wound on ceramic... that’s not the input filter of 220 which has two inductors side by side..?? would this TV have been struck by lightning..?

A trick to power all this and not burn it is to insert a 220V 60W lamp in series on one of the 220 mains terminals... thus, the current is limited... if there is a short circuit in the TV, the lamp lights up fully... otherwise, the TV is powered enough to diagnose, but not enough to run properly... that’s the idea

Hello
See the service manual.... page 49 among others
https://www.manualslib.com/manual/1192962/Pioneer-Pdp-4270xa.html?page=49&term=power&selected=62

--

 Very difficult to catch a black cat in a dark room.
                              Especially when it's not there...

And there you go, following your advice, I mounted this in series with a 60W bulb and a small pushbutton switch integrated into the Plexo outlet box, it might come in handy again.
After purely and simply replacing the 4.7 ohm resistor, I plugged it in and the bulb lit up for 1 second, the relay stuck for 1 second and cut off.
So I had just restarted the relay control circuit.
I tried again several times and checked that the diode bridge and the caps were rectifying (I had tested the components beforehand).
so I decided to connect the plasma directly and miracle it works... for 14 cents…
Two hours of perfect operation.
Oh by the way it’s very simple to power the HDMI port with just a Chromecast, in case someone didn’t know this thing...

Except that the 12V fan doesn’t spin and maybe that’s the cause of the resistor overheating.
I’m not going to close it up just yet.
If necessary, since I don’t know who is controlling it, I’ll power it directly…

Thanks and see you soon
regards

Perfect, go the Blues... once again, technique will have conquered matter...

The series lamp technique Allows to power the circuit while limiting the current... just in case, it avoids frying everything from the very first moment.. That's what you did.
The 4.7 ohm resistor is perhaps meant to burn out in a specific case... it still has quite a strong current and with time it can also die...
The fan... it might be dead..?? or maybe it is missing its supply voltage, perhaps the 12 Volts..?
If it is on the 220, it could very well have taken a lightning strike a long time ago..

In any case, it's a nice manoeuvre... Congratulations. can we set the topic to Resolved..?

The technique and… the nice tips… and a bit of cheek…

yes solved!

The fan is alive, it isn’t powered at 12V from a board full of square microprocessors. Maybe it’s only commanded when it gets hot?? No visibly damaged surface-mmount components. I’ve bombed the contacts of the connectors, nothing, so I powered it from a free connector on the PSU (there was one).
So it runs continuously off the PSU and shuts off in standby, phew :-) because it’s a bit loud…

But the TV doesn’t heat up much, the PSU heatsinks and also those of the boards on the sides. I’m really thinking of adding a fan on each side… especially there’s a (105°C) 270µF 25V capacitor right above a heatsink and it’s quite hot (almost 50°C…) that’s still risky for its lifespan…
but I need to find quieter ones…

Thanks again,
have a nice weekend