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Dx2547 power supply issues
- Thread starter kaos513
- Start date
Went to that site - pretty much useless...
They have a block diagram and even they offer a "certification" which doesn't mean squat without verification of a parts list to even prove their claims. So you may have a brick.
The Caps - have you tried sourcing them?
You may not like the prices...
It may be easier to make your own.
PDF's of their stuff attached, but not schematic.
So - many of these their layouts are straightforward - so you are on your own - they upgrade these things as parts are no longer made so they continue the line only under something else.
They have a block diagram and even they offer a "certification" which doesn't mean squat without verification of a parts list to even prove their claims. So you may have a brick.
The Caps - have you tried sourcing them?
You may not like the prices...
It may be easier to make your own.
PDF's of their stuff attached, but not schematic.
So - many of these their layouts are straightforward - so you are on your own - they upgrade these things as parts are no longer made so they continue the line only under something else.
The filter cap shown is most likely not the cause of the trouble.
The regulator circuit is probably what has gone bad. It does more to filter out rectifier ripple than the two big filter caps.
Might just be one of the 8 or 10 smaller electrolytics in the regulator circuit.
Repairing a switchmode supply is not for the faint of heart. And unless you have an isolation transformer, you can't even clip the ground connection to your 'scope to parts of it.
The price of a new substitute is a lot lower than the labor to track down a failure in that kind of supply.
73
The regulator circuit is probably what has gone bad. It does more to filter out rectifier ripple than the two big filter caps.
Might just be one of the 8 or 10 smaller electrolytics in the regulator circuit.
Repairing a switchmode supply is not for the faint of heart. And unless you have an isolation transformer, you can't even clip the ground connection to your 'scope to parts of it.
The price of a new substitute is a lot lower than the labor to track down a failure in that kind of supply.
73
I've saved $100's of dollar repairing the power supplies in my LCD computer/TV screens for friends, my brother, and myself by replacing all of the caps. Fifteen bucks buys back the $200+ monitor and that is no contest - IMO. BTW - thanks to all who helped me what I'd learned here on the forum.
Not to mention all of the radios and other things I've been able to fix and restore.
The cheap Chinese crap were definitely built for obsolescence - it's true. But if they fail before their time - and they have - then it is time to buy some caps and learn something.
Not to mention all of the radios and other things I've been able to fix and restore.
The cheap Chinese crap were definitely built for obsolescence - it's true. But if they fail before their time - and they have - then it is time to buy some caps and learn something.
That's it's "rattle" against the leaky caps...you may have found the reason for the noise, but sourcing of the noise is usualy caused by the now-inductive caps starting to fade - so pull that board out and locate traces around it to find those caps and see if maybe, just maybe - you can find a low-inductive replacement (what I mean by low inductive is due to the construction and lower grades appear as inductive loads as well)
ITs' why "Computer grade" is more of a moniker than a standard - for to allow for proper filtering you need caps but only on power feeds to reduce ringing - else on a CPU PCB the effect of signal is lost - which in a way - is the very effect caps can add to a noisy power supply line - an inductive element back into the power feed. You just need a low-inductive type and you can try to find ESL rated that may fit in there - but because of the effort the manufacture needs to put into them - they would rather do up their millions (minions?) - dump them onto the market and move on.
Get them while you can and be ready for some strange profiles that may require you to remove the shield cover so you can even mount them.
PDF explanation attached...
ITs' why "Computer grade" is more of a moniker than a standard - for to allow for proper filtering you need caps but only on power feeds to reduce ringing - else on a CPU PCB the effect of signal is lost - which in a way - is the very effect caps can add to a noisy power supply line - an inductive element back into the power feed. You just need a low-inductive type and you can try to find ESL rated that may fit in there - but because of the effort the manufacture needs to put into them - they would rather do up their millions (minions?) - dump them onto the market and move on.
Get them while you can and be ready for some strange profiles that may require you to remove the shield cover so you can even mount them.
PDF explanation attached...
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The HUM could be what is called "Magnetostriction". It is the mechanical movement of the transformer parts.
https://www.bing.com/search?q=magne...B4C9EADD403DB51C4FB533F12A09&FORM=CHRDEF&sp=1
https://www.bing.com/search?q=magne...B4C9EADD403DB51C4FB533F12A09&FORM=CHRDEF&sp=1
I would like to think otherwise - for there will always be slack from the wind - and the buzz is the indicator of a motor type of buzzer bell buzz - you just don't want the winds enamel to erode and then you may have a bigger problem - not sure of the fuses or if it even can work fast enough without perforation of other layers and the leftover remains of the tarnished stuff...it's what can smolder for long periods of time and will heat up the laminated core - to a point that in itself - is so hot it scorches the insulator "onion skin" paper.
The flammability issue is what can occur with Aluminum wiring in walls...
Mostly what I've seen, deals with non-standard, Arcade games POP and smoke out the back. The transformers they used, for say a Sega game like Q-bert - you would not necessarily hear any hum but we hear it back at the fusebox. These linear power supplies were fed by multi tap and wind All-In-Ones that even provided isolation for the CRT portion of the game as a 70 VAC line - so if something started to buzz as we learned later - it can reflect back into the line and even affect other games placed on the circuit. The kid won't die from electrocution - he's smothered in the erupting corrosive fumes and smoke
"Hey everybody! He's finally done playing the game - Excuse me sir, can I get a refund of these tokens?"
Boy we've come a long way from those days...
A lot of the games we had in our stores were not UL listed units, contained UL items listed but not all standards for isolation and emissions - dam lucky we didn't kill kids from their malevolence..
But I digress...
IF you get it fixed early enough - it should not matter. Many older power supply transformers used to "Bruup" as they absorbed the load by rattling the winds to get the caps and power supplies all filled up then as the load shifted to less inrush current they quieted down - Zeniths' were notorious for that...
Those noisy Zenith TVs used a harmonic-regulated or "constant voltage" 60-Hz power transformer.
If you can hear a low-frequency hum from a metal-box switchmode power supply, it has problems.
If you hear a hum from a 'normal' heavy, 60-Hz transformer, a bad rectifier bridge is the typical cause.
73
If you can hear a low-frequency hum from a metal-box switchmode power supply, it has problems.
If you hear a hum from a 'normal' heavy, 60-Hz transformer, a bad rectifier bridge is the typical cause.
73
Hello guys my new power supply came in doing the same humming noise wondering now if its something in my electrical system in my house.