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| General Electronics Chat This forum is for general chat about electronics, eg: Dont know what a part does? Dont know how to read a circuit? Want to get an opinion? |
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Thread Tools | Display Modes |
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After a power shortage my dvd player will not work- nothing. So, i noticed the fuse (F801 125v T 1.6 amp) was blown, so i went to radioshack and while they did not have the exact same part number, i was given a 250 volt 1.6 amp GMA type fuse-
well- i installed it- pluged in the power chord and that fuse lit up bright green and burned out. So, do i need the exact fuse outline on the circuit board or is there another problem that is blowing each fuse-??? electronics neophyte needs help- I want to watch Throne of Blood!! ** (thanks in advance) |
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The DVD player has an internal problem that must be repaired. If you can find a knowledgeable person who is willing to work on it, it may be repairable, but these things are usually intended to be thrown away when they don't work.
__________________
see my website: www.geocities.com/russlk |
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yeah, i realize that i can probably get another one for about 100 bucks but I alsways try to fix things if i can, 50 % of the time i get lucky- I thought there might be some other thing on that circuit board (where the fuse is located) that i could easily check out
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Well, you can go down fighting if you wish. Check all of the connections, make sure there aren't traces of overheating (Usually very obvious browning of the circuit board). A general cleaning of the unit wouldn't hurt. I wouldn't use any solvents, just good old soft cloth to wipe the dust away.
Other things you can do are to find the proper fuse type, and see what happens. Check for continuity, where there should and should not be continuity. Look for signs of overheated components, and replace if necessary. Make sure that when you place a new fuse in, to close the lid of the DVD player. Some units have a grounding tab that connects to the lid of the unit. Without the lid in place, proper ground is not achieved and therefore could be a point for trouble. Other than that, you're going to get complicated, and may as well get a new unit. Good luck! |
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There's nothing wrong with the fuse you tried, fuses don't really have voltage ratings (at least not to affect your problem!).
It's most likely that the switchmode device has failed, this could be a transistor, a MOSFET, or an I/C - generally they don't have any recognisable numbers on them. There's also likely to be a reason it's failed, a large mains surge could have blown it, or it could have been caused by faulty components on the PSU board - a VERY common fault in recent years is failure of electrolytic capacitors - a recent report said that huge quantities have been manufactured in Korea incorrectly, causing extremely early failures. |
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I long for the days when equipment used to be stable and would last a long time. |
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Good day!
Nigel, would you happen to know the source for the capacitor news in Korea? I would like to read up on this story. Thank you very much! |
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thanks |
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switch mode power supplies rectify the AC to DC almost directly afther it enters the device. Check the bridge rectifier, sometimes one of the diodes is shorted and causes fuse blow.
There should also be a feedback circuit with optoucoupler wich you can check but it isn't always there. The cap thing could be a lead also. I've received numerous defective pc motherboards the last year, all with defective cap's, so something really went wrong at japanese capacitor manufacturers these last years. |
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Interesting not on your problem.I also had the same problem with my toshiba dvd player,after a power outage the dvd never turned on again.I opened it up and also found the fuse T 1.6 burned and replaced it with the exact one.Blew right away.So I guess I am not alone with my 1 year old junk.Alos had a power surge bar which I guess doesn't work???? :x
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Repairing a switchmode PSU hard thing without experience. When the mains fuse blow out, most of case one or two (or more) semiconductors failed, made a shortcut. The most suspicious device the switching device: BJT or FET, but unfortunately this failure most of case destroy the IC.
Sometimes failed 1 or 2 diodes in bridge rectifier, and/or the buffer elko. When these few parts healthy in primary side, the fuse not blown. |
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It's also very advisable to change all electrolytic capacitors in the PSU, these are often a cause of PSU failure. Particularly with the huge numbers of faulty ones currently originating in the far east.
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Ok, this problem is beginning to sound all too familiar! I'm currently repairing a PS board a DVD player, with the same exact symtoms U had.
Altho I don't remember the brand of DVD player it is (possibly Toshiba), the PS is in fact a Toshiba PC-Power-2700. (Sound familiar?) This PC (power supply) had a blown fuse (obviously), D801 and D802 were shorted, Q801 was shorted, and D808 was shorted. Ya might try checking these parts in yer supply, see if the same is true. These are the parts recommended to change (some are obvious): * D801 thru D804 ... 1N4007 * Q801 .................. FS3KM (or NTE 2387, IRF830) * D808 .................. 6.8V/0.5W zener * F801 ................... 1.6A (8AG style fuse) Also, a tech note suggested connecting a 56K/0.5W resistor from the gate of Q801 to ground. As of yet, I haven't done all this, but I've been told it's supposed to work. Hope it works 4 U. Cheerz, B-o-b |
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Sorry guys,I just had posted that my sd 1700 blew after a power surge.And after sending it to get repaired the estimate was to expensive.(They quoted me $165)Canadian.So I refused and brought it home.Now I am looking into the board and found the parts you guys suggest to change(not a pro in electronics)and can't seem to find D808 diode on the board...(power pc 2700)can you give me and idea in relation to another part please..Q801 is clearly visable...thanks...
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