Re: Partial Success Repairing Vertical White Bands on HP Z30i
Hello
Thank you for the followup. That is what I was expecting to here.
lowteq
Member
Last Activity: 03-29-2020, 04:50 PM
Joined: 03-19-2013
Location: Calgary
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Partial Success Repairing Vertical White Bands on HP Z30i
Hello.
I was given a HP Z30i LCD computer monitor that had several white wide vertical bands on it. I had another Z30i that was working and after a lot of swapping of components I found that the logic board, TCON board and associated ribbon cables were healthy. The problem was the ribbon cables that go from a long slender PCB across the top of the panel onto the panel itself. The problem connection was on the PCB side not the glass panel side. These ribbon cables are attached with some kind of heat set adhesive.
I'm aware that this type of problem usually isn't repairable... -
Re: Can't Find Standbye Voltage on Toshiba Regza
This is slightly embarrassing.
I went back and tested the relay again and got a different result. When the relay operates it does close and complete the circuit, sort of... I did some checking and a alligator clip I was using to connect to one of the leads on the relay turns out to be broken, that is why I was reading infinite resistance all the time. After fixing that problem I found that when the relay closes the contact side has a resistance of between 2 and 10 ohms, it seems to fluctuate a bit.
The...Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello.
I finally had time to play with this again and did some more investigating. I pulled the relay SR81 off the board and tested it. I found some weird things.
The data sheet notes two resistance values for the coil, 567 ohm at 12V or 2.3Kohm at 24V. My coil says 12V so I assume the coil resistance should be 567ohm. When I measure I only get around 270ohm (although it does fluctuate a bit around this value).
I also connected the coil side to my bench power supply and started ramping...Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello
I removed C870 and tested it.
It's capacitance is correct according the the schematic. It measured 0.70uF, the schematic said 0.068uF.
However it does appear to be open. I tried to measure it's resistance and it registered as Open Line. Normally I would expect the resistance of a capacitor to be 0 then climb up to infinity, however I've never measured a capacitor like this before. Does this mean that capacitor is bad?
I've attached a picture of it. I know it's 0.068uF...Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello.
Sorry for the ambiguity in my last post. The 12V pins I'm referring to are 4,5,6 of P811A.
I will check C870 tonight. It is a large blue boxy one with a rounded top. It's not the usual electrolytic can style.
Thank you for the response.Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello R_J
I checked the two fuses (F870 and F871) and they both appear to be good. They show 0 ohms when measured in both directions. I also took them out of circuit and tested like that with the same result.
Pin 13 and Pin 11 of P811A both show zero volts when the TV is plugged in but not on. I can't start the TV so I can't measure that.
One other odd thing I've noticed now. I disconnected the ribbon cable that goes from P811A to the main logic board. When I did that all of the pins except...Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello.
I took another look at the power supply in this TV and I've noticed a few oddities.
The 5V1 pin on connector P811A is providing a steady 5V, I've used the schematics that budm posted to determine that is the standbye voltage, however several of the other pins on P811A are acting strangely.
The Power_TV pin has a steady 3.18V on it
Pow_DB is usually 0V put every few seconds it jumps to 4.5V then quickly goes back to 0V.
The 12V pins start at 3.79V and over a few seconds...Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
I will check the transistors, I do do own a multimeter.
I'm under the impression that if the main logic board is getting 5V of standbye power I should be able to see the steady yellow or even diagnostic flash codes, even if the TV doesn't start.
Is that impression incorrect?Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello.
It has been a few weeks since I was able to look at this. I've confirmed that my power supply board is providing the 5V standbye to the main logic board. However there is still no yellow standbye light on the front of the TV. The TV also won't start. I've tried leaving it for a few hours without luck, I also found a note that pushing the power on button for 5 seconds resets the TV, that also hasn't worked.
My suspicion is my main logic board is also dead. I'm not sure there is much I can do to...Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello.
I will take a look at the service manual as well, I'll need to install the reader to do that.
The fan doesn't try to turn on at all.Leave a comment:
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Re: Can't Find Standbye Voltage on Toshiba Regza
Hello
Here are the requested screenshots.
Is it possible to bridge the gnd and one of the points in order to cause the power supply to start so I can test voltages on the other points?
Thank you....Leave a comment:
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Can't Find Standbye Voltage on Toshiba Regza
Hello.
I've been troubleshooting a Toshiba Regza 42XV545U over the last couple of months and I've run into some problems.
The power supply is a PE0620 V28A000841A1
When I originally received the TV it had no signs of life. I did some troubleshooting and found that a thermal fuse resister R850 was blown, I replaced it. After doing this I noticed I was getting three yellow blinking lights on the power LED, however nothing else. Some more troubleshooting and I found that fuse F820 next to the SMPS chip was blown, I replaced it and it blew again immediately.... -
Re: Toshiba Regza Three Yellow Lights and blowing fuse
I've done a bit more probing around on the PE0620C power supply board for my TV and I'm finding that all roads lead it SMPS IC Q860A.
Should I order a replacement STR-Z2589? Are there any other components I should order with it.
My knowledge is limited but getting a bit better.
Craig.Leave a comment:
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Re: Toshiba Regza Three Yellow Lights and blowing fuse
It's labeled Q860A on the board. The part number is
STR-Z2589
86 10
Craig.Leave a comment:
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Re: Toshiba Regza Three Yellow Lights and blowing fuse
Hello.
I've measured the resistance between the output side of fuse F820 and what I believe to be the main filter capacitor (R821 a 150 microFarad, 450V) capacitor. The resistance was 0 ohms, I assume that is bad. I also measured between the other very large capacitor on the board (R820, also 150 microFarad 450V). It was also 0 ohms.
I've noticed there is a repair kit on ebay for fixing a blown F820 fuse on PE0620 power supplies, but it doesn't say what's actually in the kit. Is this the solution...Leave a comment:
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Re: Toshiba Regza Three Yellow Lights and blowing fuse
Hello
Thank you for the troubleshooting advice.
I've had some work stuff come up so I won't get a chance to take a look until tomorrow, but I will let you know results.
Craig.Leave a comment:
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Re: Toshiba Regza Three Yellow Lights and blowing fuse
Hello
It is the C version of the board. I've attached a photo of the board.
Thank you in advance for any help you can provide....Leave a comment:
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Toshiba Regza Three Yellow Lights and blowing fuse
Hello.
I have a Toshiba Regza 42xv545u that I've been attempting to repair.
When I first received it, there were no lights at all on the front of the TV. I worked backwards from the AC in and found that a thermal fuse resister R850 next to the bridge rectifier was open. I also noticed that fuse F820 was missing.
After I replaced R850 I started seeing three yellow lights on the front panel when I hit the power button. According to the manual that means the TV is starting, but it never actually does. I replaced F820 as well and found that it blows immediately,... -
Re: LG LED 60LS5750 No Picture but Backlight OK
Thank you for the info.
I'm pretty certain that the tcon board has failed. It appears as though there is a signal going in, but nothing coming out. My scope is an old analogue one, so I guess it is possible that the signal coming out is of such high frequency that the scope can't see it at all.
Are there any good sources for a RUNTK5119tpzz tcon board for a Sharp panel. I've googled and any place that ships to Canada is out of stock. partstore.com has it, but they don't ship to Canada.
Any...Leave a comment:
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