Found the issue, it was right between the chair and the desk. Mistake on mistake, but I did figure it out. I was tracing why those other caps don't have any voltage and it turns out there is another lower-voltage supply on the 3rd pin on that big connector. I was going off of my memory since I got back to looking into this, so that's what I didn't remember. The cases when I was able to make the board come alive must have been when I accidentally connected my power supply to that 3rd pin I guess.
What i don't understand is that voltage supply on 3rd pin comes directly from transformer (so...
jm1234
Senior Member
Last Activity: 01-22-2025, 04:09 AM
Joined: 01-12-2024
Location: Horna Dolna
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Well, spoke to soon. Sometimes the board comes alive (even with 31V bench power supply), but most often it won't. I cannot find out why. I tried to heat the board up from down below, but it didn't make any difference.
The power supply shows few mA for a moment, but then it goes into 0mA, so nothing seems shorted. The 1st 2 caps (around that burnt diode) get charged, but nothing else does.
I cannot work out how the rest of the board should get powered. Neither of the 2 DC-DC chips have any power either.Leave a comment:
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I'm so grateful to both you guys [USER="29541"]redwire[/USER] and [USER="132583"]CapLeaker[/USER], thanks a lot!redwireI'm so grateful to both you guys [USER="29541"]redwire[/USER] and [USER="132583"]CapLeaker[/USER], thanks a lot!CapLeakerI'm so grateful to both you guys [USER="29541"]redwire[/USER]Leave a comment:
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Light bulb is connected to 2 of the 4 separated pins where that longer relay is. I commented on the polarity of the caps above....Leave a comment:
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The grey plastic connectors are NOT for battery, I'm pretty sure about that.They are for start/stop and other commands. Like I wrote above, I think battery is meant to be connected to the 5-pin connector.Leave a comment:
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I forgot to mention, all the caps have their negative oriented towards the 5-pin connector and their positives towards the gray plastic connectors.
That 5-pin connector is probably for battery, but i'm not using battery, so I'm not sure.
I'm pretty sure about the 0/- being the outside pin on the large connector, because all the caps negative poles are connected to it.
As to how difficult this is to read, I'm barely making things out and I'm holding the board. I have no idea how you guys can make sense of this using pictures.Leave a comment:
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The bottom picture shows bi-di TDS soldered. One pad is missing, but it is indeed soldered on the other side of the board.Leave a comment:
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[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3494136}[/ATTACH] [ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3494137}[/ATTACH]I had an older picture without the caps, should be easier to trace.[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3494136}[/ATTACH] [ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3494137}[/ATTACH]I...
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Not saying I don't need to learn, that is absolutely true. I just took the lazy path of following your advise literally, without thinking further. I see the PCB, not you, so I should have traced more before asking.
Anyhow, I shorted the TVS and it started to work. Coming back to my original question, what should I put instead of that burnt component. Knowing now, that this component connects + poles of the 2 big caps, I think GDT doesn't make sense, as it doesn't conduct under normal circumstances.
As for uni-directional TVS, it would pass the current in one direction, so the device...Leave a comment:
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Just got back to this, sorry about the delay. I bought TVS [url]https://www.tme.eu/ie/en/details/1.5ke68ca-cdi/bidirectional-tvs-tht-diodes/cdil/1-5ke68ca/[/url].
When I put it in the PCB, I noticed tha TVS is connecting + poles of the 2 biggest capacitors. So I can see the supply voltage on the 1st capacitor, but it doesn't get to the 2nd capacitor. That's a homework I should've done before bying TVS, sorry about that.
If I understand this correctly, TVS isn't the right way to address this, as I need that voltage to be passed onto the 2nd capacitor (and the rest of the board). Instead...Leave a comment:
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Both caps are bulged, need to replace them. I think the only other thing that popped was fuse on 220v side.Leave a comment:
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Thanks for the suggestion, just learned something new again :-).
However, thinking about it some more, my bridge rectifier was not damaged, it still produces those 50V. Not sure how would high voltage appear on that GDT to burn it then?
Also, does it seem the right place for GDT to put it after the bridge rectifier?Leave a comment:
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actually it's rectified 35V AC, so it's 50V DCLeave a comment:
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Better focused picture
[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3298455}[/ATTACH]...Leave a comment:
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Garage door module Nice SNA4/A - burnt component
Hi,
I'm trying to guess what component got burnt on the control board for my Nice garage door motor Nice SNA4/A. You can see it in front of the 2 capacitors. The component is connected across the 36V rectified input wires, maybe it was some kind of protection device?
All the pictures I could find were of the whole product, so enclosed in the plastic box, eg. [url]https://www.ebay.co.uk/itm/123998876212[/url]
Any help appreciated.
[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3298448}[/ATTACH... -
I found a disfunctional optocoupler on the SN board, replaced it and the issue is still the same - 6 flashes. :-(Leave a comment:
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Thanks, but I don't see any data sheet for either 9157 or PS9157.Leave a comment:
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optocoupler? B3PBE0000060
Hi,
I'm troubleshooting SN board of Panasonic plasma TV and I'm curious about a component that looks like an optocoupler, it has 5 legs though. I tried to check between legs 1-2, but no diode junction there, it's open. So either that is not a diode there or it's burnt.
For future searches, the part num is B3PBE0000060, the label on the component says 9157 and N219.
Any idea?
[ATTACH=JSON]{"data-align":"none","data-size":"full","title":"image.png","data-attachmentid":3277057}[/ATTACH]Hi,
I'm troubleshooting... -
Panasonic plasma TX-P42ST50 - 6 blinks
Hi,
anyone able to provide the service manual for old plasma Panasonic TX-P42ST50E?
It turns off almost immediately (0~5 seconds after pressing the on/off button) and starts flashing the red diode 6 times.
I disconnected the left-hand side board (SC?, both the ribbon cable and the power cable to it) and also another ribbon going to bottom left board. Then the led signal is 8 flashes. According to service guide to another Panasonic plasma it would mean the left-hand side board is faulty. But I'm not sure it 100% applies to my model.
I checked that board for any obvious faults... -
You're probably right in that, but there is no way to order specific rank as far as I can tell, so that seems puzzling. Anyhow, I ordered that LTV-816 from TME and what arrived is labeled 816B. I put it on the PCB and the issue is gone now. So I consider this a success, knowing well it's too soon to claim any victory here.Leave a comment:
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