Re: black screen magnavox 42mf231d/37
Where did you get the idea that these buffer chips are compatible between the magnavox and the toshiba? Thats a ballsy move unless you had the chip numbers with the data sheets to prove that they in fact were compatible.
What exactly is the buffer chip make and part # for the Toshiba buffer?
You must have some good desoldering equipment or are very skilled. The pitch on these chips is pretty tight. I wouldn't be as worried about getting them soldered in as much as damaging the good chip from the...
mrosenberg42
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Last Activity: 08-05-2020, 10:32 AM
Joined: 08-29-2008
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Re: Philips 42PF9630A/37 horizontal lines
Quick update on the progress of these Plasma's.
I decided to take the good buffer boards and put them in the set that also had the horizontal lines across the whole picture to see if it would exhibit the same issue I was seeing on the other TV.
Happy to say that after replacing the buffer boards the picture has not exhibited any of the problems the other set was having. But Damn this plasma produces some heat.
Since I have a USB port on the TV I was thinking of adding a USB fan to pull some...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
The buffer board was purchased brand new from a reputable company. This is actually the second one they sent me because the first had a dead buffer chip which showed up as a black band in the screen.
This second board I assumed to be new as well but doesn't have the normal heatsinks that I have always seen on these boards. So this one could be rebuilt. The original purchase had a 90 day warranty so I should be covered. It's been about 3 weeks since the original purchase.Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
Check out Coppell TV repairs latest blog about these particular buffer boards. He says "horizontal line or lines of pink / red sparkles is clearly a buffer on its way out". Which is exactly what my set has going on.
So now the million dollar question: Is the buffer board I just bought good or bad? It seems to work fine till it heats up. Which seems to be an indication of buffer chips going bad.
If I wasn't worried about throwing money away I would order a new logic board and go from there, but these...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
I agree. I guess where I am confused is what is causing the buffer to be driven in excess. A problem in the Y - sus or the logic board? And also why the lower buffer board is not seeing that same excessive load?...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
Even with the cover off after a couple of hours it starts to show the lines, but if I cool it down with a fan the lines cease until I turn the fan off and it heats back up.
I will swap the logic boards between the two and see if the boards make a change with the swap.Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
Here are pictures from the set where half the screen is good. I have checked the buffer board for shorts with the method described by coppell tv repair and the board has no shorts and seems OK. Although the heat sinks on the buffer chips get quite hot. Could this be connector solder joints not making good contact on the buffer board?
For a test I put the new upper buffer board back in. With the back cover off I let it run for two hours. No problems. After the two hour mark the buffer chips on the new board start to heat up...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
Wizard,
Thanks for all the help. One more question. Like I said early on in the post, I have 2 of these TV's exact same model number one has horizontal lines throughout the whole screen as pictured above and the other has horizontal lines only through the upper half of the picture (have not attached a pic of that set).
Is it possible that the logic board would cause the problem on only the upper half of the screen while the remaining lower half of the picture is perfectly good?
Both tv sets have the...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
With the old upper buffer board in the horizontal lines are always present. With the new upper buffer board in the lines are now gone but after about 15min of the set warming up with the cover on the lines started to slowly fade in, which is when I turned the set off.
The lines are there regardless of input and are also there with the menu up when the old board is installed (the original upper buffer board).
Wizard,
If the problem is the logic board like you suggest from your hint (because the horizontal...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
So after way too long I finally ordered an upper buffer board. I put the board in and the picture looked great. So I put on a dvd with the back of the TV off and let it run for an hour burn in. No problems.
So I installed the back cover of the TV and let it run for about 20 min. and the lines on the upper half of the display started to reappear.
I quickly shut off the TV to avoid damaging the upper buffer board that I just put in. Let it rest for about 15min. and turned it back on. No more lines seen.
...Leave a comment:
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Re: Westinghouse Sk-26h735s
I took another look at the picture you attched of the inverter and looks as if there is another smaller fuse next to the larger one. Check them both. Here is a pic with both fuses circled....Leave a comment:
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Re: Westinghouse Sk-26h735s
Something you can quickly check is the fuse on the inverter board. I circled it in the attached pic. Check whether it is short or open....Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
Thanks for the comments. All very helpful. That you tube video is very interesting. As I have been in the electronics industry for years I am sure the soldering won't be a problem I'm just not sure that the buffer chips are the problem. Maybe other components on the board. As Wizard said it may be a bad logic board or main board. As I am not doubting the knowledge of someone who knows infinitely more than me and always will, I still think the buffer boards are the problem. I have read numerous forums of people with the same problem that...Leave a comment:
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Re: Philips 42PF9630A/37 horizontal lines
Someone has got to have some knowledge of these buffer boards. There are a few companies on ebay that are giving a core of $25 to send in your old board after you buy a refurb from them. They are fixing them and reselling. Anyone?Leave a comment:
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Philips 42PF9630A/37 horizontal lines
I have two of these plasmas. One only the top of the screen has these horizontal lines and the other plasma both the top and bottom of the screen has the horizontal lines. The lines seem to be red, green, blue and black. I have done alot of research and this seems to be a buffer board failure. My question is what specifically on these buffer boards are failing and can these be repaired to the component level? I would like to repair the boards rather than swapping. I read somewhere that these might be cold solder joint connection issues but we all know that would be just to easy. I believe I can... -
Re: Protron PLTV-32c
Thanks for the reply. I did check ESR of all electrolytics and all measured ok. The filter Cap is at 160v which is 1.4x as you suggested. I am definitely missing something. I still don't trust any of the caps. Like I said earlier I'll start with recapping the whole supply check the smps chip voltages and then work through the other components one by one. Thanks again.Leave a comment:
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Protron PLTV-32c
Hello all,
I have a Protron PLTV-32c that has no standby power or any other voltages for that matter. I read the posts about the PLTV-3250 and it sounds like the same issue but a different power supply. I checked all transistors, diodes, zeners and found no bulging caps. Everything checks out ok. Granted everything was checked in circuit and no components have been pulled off the board and checked, which will be my next move. I think I'll start with replacing all electrolytics and then pulling off zeners and checking them outside the circuit. Does anyone by chance have a schematic of this... -
Re: Akai 27" Turns on and off and on and....
I fixed an LCD monitor with a similar issue. It ended up being a shorted transistor.Leave a comment:
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Re: Hitachi 55hdx62
Thanks Wizard. The poly cap is actually in the early stage of the power supply. Would the power supply be fairly sensitive to esr? Also how did you know it was a 43nF cap? Is their a database to find these values? the smd cap is located on the main digital board. There is another one of the same caps that measures an esr of .42ohms while the suspect one reads 3.2ohms. Thanks for the info.Leave a comment:
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Hitachi 55hdx62
I have a Hitachi 55hdx62 that will not power up. The power supply shuts down in about 1/2 a second after pushing the power button. I have gone through almost all components on the power supply the x sus and ysus boards. Their are only two that I am suscpicious of. One smd aluminum electrolytic cap and a much larger cap. I cannot find any data sheets on either capacitor. The markings on the small smd cap are 5J 22 JLD. I also tried to find a data sheet for the other larger capacitor. But when I do a google search I get nothing from the part number on the cap. The large capacitor measures an ESR...
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