Someone tossed out this Toshiba 50L3400U HD TV. It turned out to have a faulty LED driver chip, which was replaced. It seems that thermal management of this chip was not designed very well.
Toshiba is low end chinese stuff anymore. That's why the generic chip that runs hot. Seems like most of brands we grew up with in the 80s and 90s are just low end chinese products anymore. Sad state they are in. I'm still using a mid 2000s Panasonic plasma TV that's been great. Lost a mosfet in a driver board once, replaced that and she's been great. Keep up the videos!
The logo on the PSU board indicates FSP group / Fortron power supply. They make power supplies that work. That's unfortunately all there is to be said. Quality isn't their strong suit as far as my experience with their pc power supplies goes...
100% right. They are used by many big name brand manufacturers, but i have also seen many of them failed. They work and they have a power supply in every form there exist, but that said, they don't last long.
@@MrDubje , they are a OEM manufacturer for many brands, they are also by Medion in there desktops, and for there notebooks. Even in Watchguard firewalls, which i don't understand from such expensive brand.
I like the fan idea. Have to figure mounting to rear cover, possible rf interfearance, power takeoff. Oh, don't forget, once fan is up and running how do you deal with dust clogging potential.
@@jdmccorful Laptop fans are squirrel cage so a rear mesh dust filter made from screen door material. RF interference ... like what the fan will do in a laptop? Yeah, no. I have ziptied fans to all sorts of things in the past with zero issues.
Logo on PS-PCB is that of Fortron Source, maker of (generally not too bad) PC Power Supplies. Personally would tightly screw another heat sink (extruded aluminum profile as big as allowed by back shell) to existing sink, adding thermal paste.
Reminds me a little of Behringer PSUs. Sorry. - I like the idea of adding a small cooling fan. Probably can extend the lifetime of the TV until something unrepairable breaks down.
I'd want to add a bit of heat sinking to that little FET. Difficult to do though. Adding a slim heat sing (motherboard chipset type) to the IC may help as well. You have thermal glue ;) And don't drive the backlight at max, but keep it at 89% max.
The manufacturer's logo on the PCB is FSP group, see here for visual confirmation : www.fsp-group.com/en/index.html (not sponsored or affiliated, just being curious)
Would be interesting to see your version of a driver. To measure, design, prototype, test and retrofit an appropriate led driver to the unit. I'd love to see how your unit accepts and interprates the pwm and enable signals.
I would increase the heat sink, also add some fins to it. I wonder if it is not possible to grind some of the chips's plastic in order to get closer to the die. How on Earth did the O2Micro designer thought this throuh?
I would get an old 90's heatsink for Intel microprocessors and put it on the aluminum heatsink. My guess is this chip will also fail but if lowered to below 50° C it will last till the cows come home.
As to a fan, this is to be used in a-usually-quiet room. Fans will add noise, maybe a small amount, but it will be louder than nothing. Measure temperature again and reduce the brightness. Does the temperature change?
Thank you (again) for the video, your lab might be small, it is a nice one, and you have a dedicated place. Also, watching a repair like this, which is different from the channel's favorite repairs (portable scopes, audio gear, microphones, music stuff) is nice. Your channel deserves much more audience and subscribers.
Hi, did you attempt to re-bond the original chip to the heatsink at all before deciding to replace the chip? Just wondering if the blinking could have been due to the thermal protection cutting in and out if the original thermal bonding had failed.
Excellent repair of a poor design. As others have suggested I wonder if some active cooling might extend the life of that chip. Did you check the temperature of the MOSFET (or circuit board area under it)?
You are very careful in you work... but i am curious if you determined if the device is being over-driven to its high thermal state by that power driver (linear regulator?).
I have a question for you my audio in my 50-inch TV will not stay on it goes back to zero no matter what I do. I've troubleshooted with Toshiba and they think it's an internal problem in the TV do you have any suggestions or is it worth fixing?
Hello, I'm Carlos from Brazil, I would like to know where I can buy a 6-digit precision multimeter, I see some equipment that we don't have here in Brazil, I would like to know if you have to sell or know where to buy these electronics test equipment used by a affordable price? thanks for the videos i really like to see the equipment repair !!! Congratulations
the heatsink is just a flat metal piece with no fins! For me this is the worst part of the design. I would try and fit another heatsink with fins and add a small 30mm -40mm fan. Had they used the SOP package it probably would have a heatsink pad under belly and with a large ground plane the heat could be dissipated quite reasonably. This is really a cheap design
Thank you for the video and information, but I put a dislike, because with Your level of knowledge, it was possible not to repair a deliberately bad circuit, but to make your own reliable control module, which would not contain a "planned failure". for a couple of seconds on the capacitors and chokes, you can make a current source from AC mains voltage without ripples of illumination, and if you spend time, you can make a controlled illumination. And I'm also surprised that You didn't change the electrolytic capacitors, because it is very obvious that they were put there at a minimum, and they are already a little dry. And heating the radiators accelerates the drying of the capacitors. And they cost a penny, sometimes it turns out to find capacitors just a little bit larger in size, but already from the "long-lived"series. Sometimes even "ultra long-lived". The power module appears to be marked by the FSP group
You set the bar to earn your like too high. I am afraid I cannot live up to this standard. And by the way, the capacitors measured perfectly fine. Thanks for your attention.
