#16
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You better take pictures before taking them out. And they are polarized, so remember
or make sure your pic is clear, close, and shows polarity of each cap you remove... Don't bother testing something that is bulging, or leaking, it's going bad, it will soon go POP, so get new ones. A few volts higher rating would be nice.... .
__________________
Yes you can call me "Squirrel boy" |
#17
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I thought about that already, since 3 are 1000 MF@35 and I believe the other 3 all in the same are are 1000mf@16 volts. The only thing that might make it interesting is the area is kinda tight, make make installing higher voltage ones "ugly". A couple of 16 volt are almost touching a heat sink now,35 volt caps would be bigger and hitting it. Now I will admit I see nothing attached to the heat sink so it in this case may be to match the height of the rest of circuit board in order for a cover to bolt on to "something " in this corner so maybe that won't hurt anything.
And with the price of these caps a little experimentation may not hurt |
#18
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its the caps in the first picture i posted.....the only clear pic!
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#19
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I guess one thing so far is a good sign...the fuse on this board isn't blown so hopefully nothing else went bad.
I was told on this site not to even turn it on...which I understand why but I already did because the owner tried for a long time to see if it would ever work so I figured any real damage was already done. I hope I am not wrong! |
#20
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Well you don't have to go to 35v from 16v. You can do 20v, or 25v. And there are times
when going to opposite lead layout and putting some insulation over the leads as you replace the cap will help the ugliness factor out. Don't forget there can be at least 2 good possibilities for these newer caps going bad. They skimped on the design and used a 16v cap in a 16v circuit, leaving no margin. or the manufacturer of the caps skimped and the caps really will not last at the 16v level. Also, if they skimped on the caps, they most likely skimped on the more expensive parts too, and maybe some of them may not be available when they fry, so don't outclass this thing with Lexus parts.... The rest of it may not last.... .
__________________
Yes you can call me "Squirrel boy" |
Audiokarma |
#21
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one output is 24 volts ....written on bottom of board and the other i "believe" was 5 volts. 24 i am positive but not so sure on the other. I'm at work on break and the board is at home. i am pretty sure there was enough leg room on voltage though. must be poor quality caps.
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#22
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I tried the net and so far this power supply board is not available to purchase, and if it is it's probably not cost effective either!
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#23
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Yah, they know the life of the unit as a whole is most likely pretty short.
.
__________________
Yes you can call me "Squirrel boy" |
#24
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well, just yesterday had the time to remove the caps, and sure enough on a heathkit cap checker they tested fine at low voltage and junk at circuit voltage. ordered new ones and now its the waiting game for the new ones to get here.
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#25
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Regarding realestate of the caps on circuit boards, most manufacturers have reduced the size of the can over recent years and/or offer a taller profile (same diameter) and at the next higher voltage range (say what was 16V and now is 25V) to give you some more margin. This is why many use the very good parametric search engine features like Mouser and DigiKey have when shopping for components. As others have said, a failed 47uF 16V 85deg-C high frequency switching power supply cap in a 15V circuit is a very poor margin. To me it should be a low ESR, 25V 125 deg-C pro-active replacement type; maybe also upping the capacitance to 63 or even 100uF to get the ESR even lower.
Tom (PK) |
Audiokarma |
#26
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...
Last edited by andy; 11-20-2021 at 03:51 PM. |
#27
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I've always used 35 volt caps where the originals were 25. With the newer Panasonics, the sizes are the same as the 25 volt versions. At the last Samsung seminar I attended, the reps were recommending the same, as they had run across some 24 volt supplies with 25 volt caps in them -no margin whatsoever. I just finished three Insignias that all had bad caps, and went up in voltage (with a corresponding drop in ESR) on all but the four 16v caps for the 5v/3.3v standby circuit.
My favorite caps are the FC and FM series from Panasonic - where going up in voltage always yields a higher ripple current and lower ESR. 680@25 - .052 ohms ESR, and 1220mA Ripple current. For the same in 35v, the ESR drops to .035 ohms, and ripple current increases to 1815ma.
__________________
Brian USN RET (Avionics / Cal) CET- Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit! Last edited by Findm-Keepm; 10-09-2014 at 05:18 PM. Reason: Added comment on caps |
#28
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ok, caps came in, put them in the power supply....and nothing. But I am curious the smaller board sends power to the main board. how much AC does it send to the main board? I tried powering it up but the main board has zero input AC. Also, the "mini" board was showing 3. Something DC to the small connector and 125 Ac on the big connector going in .
Even with me hitting the power button the DC to the mini board stayed at 3.4 or so ...Do I have to have a dvd or something hooked up to get it to respond or is something else wrong here? |
#29
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Just watched you tube video link on earlier post for this problem....since the mini board makes the standby power and my standby voltage is low then there is a cap on the mini board that is bad also. correct?
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#30
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i removed the 470mf cap on the standby board and it tested ok on a heathkit cap checker ,but then i got real curious and put it on a digi-bridge and it came up as 32 mf. wow. i put a new 25 volt cap in instead of the 16 volt one that was in there and when i get home after work(second shift) i will try this tv again.
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Audiokarma |
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