I have been working on this tv for ages and I am not having much luck. I have replaced the smps and have purchased two ysus boards. I bought both ysus boards on eBay so I'm sure they all had the same problem. All the voltages coming out of the smps are correct. The only voltage that is off is the vy voltage. It's setting at -105 and should be -190 it will stay constant for a few seconds, then flash and go back to -105. None of the capacitors look bad although I haven't checked them with my esr meter yet. It's only letting me upload one pic at a time so I will post more after I transfer them from my iPhone to my computer.
50pg20 maldischarge
Collapse
X
-
Re: 50pg20 maldischarge
Z-SUS board faultI would say--But check ALL the supply voltages, Vs, Va, VSC, -Vy, VZ-Bias first...TELEFIX
How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
http://www.irf.com/technical-info/appnotes/an-1088.pdf
PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!Comment
-
Re: 50pg20 maldischarge
How did you determine the transformer to be bad?
Note, SMPS transformers are very reliable and they very rarely fail!Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
For service manual, schematic, boardview (board view), datasheet, cad - use our search.Comment
-
Re: 50pg20 maldischarge
I replaced the zsus to no avail. Also, Turns out I was wrong about the transformer. I checked the vy voltage and it appears that if I place my probes on either side of the resistor, I get the proper voltage readings. But if I place one probe to a lead and the other to chassis ground the reading is poor and fluctuates. I'm not sure if that matters or not. I consulted the service manual and the readings that I get when testing the buffer boards are off. They all seem to be lower than what they should be. I'm in the process of buying new buffers so I'll update this when they come in. Anything I should check in the meantime? Thanks for the help.Comment
-
Re: 50pg20 maldischarge
Not a Y-SUS fault. a y-sus/buffer issue will give horizontal lines, not vertical.
Summit to do with the vertical address (COF) chips, their data-lines, or the tabs to the glass of the panel.
Check where the tabs containing the COF Chips attach via ribbon-plugs to the boards that run along bottom edge of the panel, check all of the ribbons to those boards.
You'll have to remove the ally heatsink along bottom edge of the panel. Take great care, those COF are very delicate, easily torn/damaged, and do not run set without heatsink refitted.
You May get lucky, but in my experience, vertical lines on Plasmas usually ends up being one or more of the COF chips and is unrepairable.TELEFIX
How PLASMA SCREENS WORK, X-SUS and Y-SUS what they do--
http://www.irf.com/technical-info/appnotes/an-1088.pdf
PLEASE DO NOT EMAIL ME PRIVATELY FOR REPAIR ADVICE. QUESTIONS BELONG ON THE FORUM!Comment
Related Topics
Collapse
-
by dkneyleThis relic from a technology path that came to a dead end (but still has historical interest) was brought in with a dead SMPS, which is based around a MK1210 device. I got it going after a battle. It seems to have a strange design - if it's not getting feedback that the secondary is OK it cause the big FET to go into full conduction and overloads resulting in a blown fuse at best or something worse! I'm using a Dim Bulb Tester (70W/230V) which thankfully has saved the day a number of times whilst repairing.
Now, it loads a CD OK. The motor voltage output (which is built onto the SMPS... -
by shamsudeenHi all, I just need to know that, can i use SMPS type power supply to test and short circuit detection on a laptop motherboard?
I saw 95% of repair guys are using only Linear bench power supply. linear bench power supply is pricy, thats why i planned to get one SMPS supply.
i know that in linear power supply the noise will be very low comparing to SMPS supply.... -
by leggLG42PC3D -UD originally with green lamp but no display or audio.
Owner says was working, then went 'pop'.
All 5V caps bulging. replaced.
All PSU output voltages within spec but -Vy is low on YSUS.
One of three parallel fets between SUS_OUT and SUS_DN is zenering,
eventually shorts DG. Replaced all 3 - -Vy now OK.
Y scan buffer test point does not follow YSUS output below -50V
Note: This unit seems to expect YSUS output to park at -Vy in between
drive signal pattern periods. A replacement drive signal board confirms this....11-18-2021, 11:49 AM -
I have this Huntkey HK340-72FP PC SMPS where I am facing a strange problem where the SMPS shuts down when the load on any of its 12v output rails goes above 2 amps while the rating of each 12v rail is above 10amps capable.
I have checked the following:
1. All output caps are OK, and all output rails read correct voltages at no load
2. All output diodes are OK
3. NTC is ok
4. Hi voltage cap on input correctly reads 150uF on LCR meter per the spec, also the bridge rectifier is OK
5. No short in main switching MOSFET
6. All other components... -
by madan1Hello,
I'm troubleshooting a PA speaker Mackie Th15 (schematics attached).
It is basically a smps with amp and some dsp.
The issue is that on the secondary side I read +/- ~23V instead of the expected +/- 38V. Indeed all secondary side and feedback/aux rails are like 1/2-3/5 of the expected values.
Q2, Q3, C35, C40, C33, C36, C41 and C42 were tested out of circuit with a component tester and read fine. Most of the other components on the primary were tested in circuit and seem to be fine. +HV to -HV on primary is ~330V.
By the way, the ferrite core of L10 is broken,... - Loading...
- No more items.
Comment