• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Toshiba Plasma power supply buzz. red light blinking.

Status
Not open for further replies.

fastline

Member
Toshiba 42HP95. They are well known for killing the Seine board I guess but they can be tested out by removing power from that board and that did not work. When power is applied, the PS will fire a relay on the board, bring up 2 fans, wait about 5 seconds, then kill the fans and throw the famous red blinking light.

I am still learning on power supply repairs. Not sure if this noise from the supply is normal or not. It is a buzz but only audible from about 2ft away if you are listening for it. I removed every load from the PS and it still makes the same noise. Coming from the inductors it seems. Bridge is good and never blew a fuse.

Also, I am NOT a TV repair guy. After testing the PS with no loads, I was going to reattach the plugs and when I tried reconnecting the Vsus plug, I got some arcing. I realize things were charged up and I did not connect it wrong but wondering if this is a poor practice and can damage anything? I am used to the old TVs where there was a service switch to drain the caps but these don't appear to have anything.

I am very much suspecting the power supply but honestly pretty overwhelmed. All caps "look" fine. Probably about 30 FETs on it so that will be fun.... Just not real sure what I might be looking for if that buzz is deemed an issue.
 

tunedwolf

Well-Known Member
I don't have a great deal of experience on Tosh Plasma's, but I'm guessing at a couple of diodes and FET's being goosed on the power board. I seem to remember them being on the end of a heatsink rather than in the middle. Check the 15V rail, it's pretty common for the cable decoder/ card reader to pull it down. Disconnect the 4 way plug going to it and see if the 15V rail reappears.

Don't run any switchmode power supply without a minimum load attached, simply put they don't like it. I only ever went to component level on Pioneer Plasma power supplies due to them blowing up every week (it was faster to just fix it than wait for a replacement board) but other than that, I just replaced the board, no hassle, warranted repair for the customer.

rgds
 

fastline

Member
ESR meter on the way. I am still blown away over the price. You can get a Craftsman digital multimeter that is reasonably accurate to do about 50 functions for 50 bucks, or a meter that just does one function and I have to assemble the whole thing for 100 bucks!!! What is so special about this circuit?
 
Last edited:

tunedwolf

Well-Known Member
Its ability to measure the equiv series resistance of a capacitor without having to get your soldering iron hot...
Also quite handy to find those pesky little decoupling caps that insist on going short circuit...
Although, I think I would have spent a little more than that and bought an Atlas ESR80, but then I'm a snob when it comes to tools :)

rgds
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top