Help identifying blown part on Sony BDP-S590 Blu-Ray player. - Page 1
Forum section: electronics / repair

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 01:01:02 am
content: I need some guidance.I really don't know where to begin. I have never tried to fix anything before, but as I age, I'm getting tired of replacing hardware. I swear this stuff is laughing at me, no, taunting me, and before I take a hammer to it, I'll give it a go and maybe learn something.Anyway, I have a few items around here in a constant state of laughter...This is a Sony BDP-S590 Blu-Ray player that was most likely in a lighting strike. The attached image is the power supply board with the 110 cord attached. I've noticed a blown " transistor "? At least I think its a transistor, as it has three leads.... Okay I don't know what it is. Searching the Intertubes has proven very useful.How does one figure out what that is?I'm sure there are some threads that show you to to do trouble shooting like this, but I haven't clicked on one...Corey

author: theatrus
author_rank: Frequent Contributor
timestamp: July 04, 2014, 01:24:53 am
content: The only semiconductor in this picture is the one labeled IC201 - is that the part in question?Any chance of reading the markings on it? The SOT-23 won't have much. The pinout labeling (nice!) or A/K/R is also interesting, which might indicate a reference.

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 01:34:34 am
content: Yes, the IC201 is the blown part. I can't read anything on it.On a different board there is another similar sized semiconductor labeled " K-1 ". What are the odds they are the same thing?

author: theatrus
author_rank: Frequent Contributor
timestamp: July 04, 2014, 01:41:33 am
content: Quote from: trnkyit on July 04, 2014, 01:34:34 amOk, I see it appears to actually be split in two. This is concerning, especially if it is after the transformer. Its likely this is not the only dead component, just the most visible. Can you trace out where, roughly, it lies in the circuit? There do the labeled K/A/R nets go?The SOT-23-3 package is used from everything from diodes, to BJTs, to FETs, to references, and even sensors (1 wire).

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 01:58:54 am
content: Here are some expanded shots. Front and Back of the board.The blown IC is after the transformer I believe. Well its on the ' secondary ' part of the board so I'm assuming that's after the transformer.I'll do some traces and post tomorrow my results.Thanks for helping. I realize it can get frustrating with newbies, as were slow and stupid.But hey, I've already learned how to look up a Z-1 IC. Its a Fairchild Zener Diodes 22V 0.5W

author: amyk
author_rank: Super Contributor
timestamp: July 04, 2014, 03:31:19 am
content: I'm 99.999% certain it's theTL431for the control loop, given the K, A, and R designations, and the fact that tracing the schematic (attached) reveals the standard circuit for one. According to the resistor values the output voltage of this PSU should be 2.5V * (82k + 22k + 27k) / 27k = 12.1V which also makes sense.

author: Rasz
author_rank: Super Contributor
timestamp: July 04, 2014, 08:06:06 am
content: start by connecting 12V directly to the BD player and checking if its alive, no point fixing this psu if player got zapped by lightning

author: Kjelt
author_rank: Super Contributor
timestamp: July 04, 2014, 08:16:36 am
content: A warning before you get frustrated, devices that suffered a lightning strike usually have a lot (and I mean a lot) components damaged depending on the impact of the lighting and the way through the device.

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 12:53:39 pm
content: Quote from: amyk on July 04, 2014, 03:31:19 amAmyk, that looks spot on. The front side of the board actually says UNSV 12V. The chip being a Unisonic.How did you come up with this? Experience? Or were you able to figure out the source from other components on the board? Curious.

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 12:55:40 pm
content: Quote from: Rasz on July 04, 2014, 08:06:06 amRasz, keeping it newbie, how do I figure out the Amps required ? I looks like pins 1,2,3 are + and pins 4,5,6 are ground.

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 12:58:02 pm
content: Quote from: Kjelt on July 04, 2014, 08:16:36 amLightning... Yea I understand its a long shot, but, there's still much to learn from this exercise.I would have thought, I would see more damage everywhere, but this is the only spot I can see. Everything else looks great.

author: Rasz
author_rank: Super Contributor
timestamp: July 04, 2014, 05:03:22 pm
content: Quote from: trnkyit on July 04, 2014, 12:55:40 pmthis psu does 5A maxhttp://www.mitsumi.co.jp/latest/Catalog/pdf/power_srv_e.pdfold PC power supply will do

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 07:56:33 pm
content: Quote from: Rasz on July 04, 2014, 05:03:22 pmRasz,Thanks man! I tried your suggestion and it works!So now I'll focus on trying to get that damaged part and see if I can fix the power supply.

author: theatrus
author_rank: Frequent Contributor
timestamp: July 04, 2014, 08:38:40 pm
content: Cool!I'd go through and verify the following on the power supply:- capacitors are ok- power semiconductors aren't shorted- resistors are ok- isolation from primary to secondary remains intactHaving just the reference explode is a bit unusual

author: trnkyit
author_rank: Newbie
timestamp: July 04, 2014, 10:45:22 pm
content: Quote from: theatrus on July 04, 2014, 08:38:40 pmTheatrus,Thanks for the checklist. This should keep me busy. I just wonder if I'm going to be able to find the blown part. Maybe I can substitute for something else...

author: theatrus
author_rank: Frequent Contributor
timestamp: July 05, 2014, 12:54:56 am
content: If it's actually a TL431 (seems likely), they are everywhere.http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=ZTL431AFFCT-ND

author: amyk
author_rank: Super Contributor
timestamp: July 05, 2014, 03:32:03 am
content: Quote from: trnkyit on July 04, 2014, 12:53:39 pmJust some experience with designing, modifying, and repairing SMPS. The TL431 is used in almost all the ones that do secondary-side sensing with feedback through an optocoupler, and the circuit has little variation; here's another one:http://www.electronicrepairguide.com/images/schematicsdiagram.jpgAlso, when you first test it, make sure to power it up with a small dummy load, preferably a power resistor - this is so that you can verify the output is regulated at the correct voltage and not risk further damage to your real load. Defective components in the feedback circuit can cause the output voltage to rise extremely high.

author: SeanB
author_rank: Super Contributor
timestamp: July 05, 2014, 04:56:58 am
content: I know, a nominal 5V supply with dead caps on the secondary side I checked with a resistor load, and it was happy to deliver over 50V to it. Replaced the caps, and it was 5V again. Too bad for the hotel that had to buy a new room card writer, it was well cooked. I did suggest the new one have a 6V8 5W transorb on the input side as added security.