How hot should a resistor get?

[tvtech]

OK. You say the supply is blinking. So, I assume it has an LED that is flashing on and off on the PSU?

What happens if you disconnect the output leads on the supply. Does it still blink then?
Why I ask this is because the supply could be going into protection with load connected.

Just a thought.

 

[parkerbeder]

This power supply is for a sound mixing board, a Mackie Onyx 1640 to be specific. When it powers on, the mute lights on the channel strips light up. It really doesn't have much of a load at idle. I foudn another person who had the same problem that I had at first (the fast blinking) he had a parts list from the repair shop which included two voltage regulators, and a darlington controller (it's a to220 package with like seven pinsis all I know about it... I'm a mech-e, that literally maxed out my electronics knowlege writing that sentence ) Anyway, I ordered those parts, and am hoping that does it, but i'm still game to keep troubleshooting if you are, tvtech. I'll hook up my test meter to the outputs, and unplug it from the board, if that's what you recommend next.

Thanks again!

-Parker

 

[tvtech]

You have nothing to loose by reading the output voltages and seeing if maybe they are at least stable with no load.

Check 'em out and post back here.

Cheers

 

[parkerbeder]

Okay, it looks like they put something out, then slowly drain back to zero, after maybe 30 seconds they put something else out again. Just hooking the voltmeter to them drains them pretty quick (assuming voltage stored in the caps) while reading maybe lasts 20-30 seconds till it's dead. It probably lasted so long because it was just running 16 led's

-Parker

 

[Sceadwian]

if functional parts were replaced with identical functional parts?

Such is not the case, the poster already stated that some of the caps that were replaced were larger than the originals, no specifics were given as to all the values that changed. This entire post is a crap shoot, there is no solid detailed information being supplied, only rough guesses and hunches.

 

[tcmtech]

What I see in the picture is a 100 ohm resistor which is near a what is likely a NTC device of some sort.
A blinking power supply can mean that the over voltage or over current protection circuits are cycling as well.
With out a schematic or more pictures to go by I would suspect a bad capacitor or diode on one of the output stages or a honest power overload is present either from a internal partial short or external overload.
Possibly one of the protection circuits has just drifted out of its correct working range and is shutting the unit off because it thinks something is wrong even though its not.
Just a guess though.

What are the power supplies input and output specs?

 

[parkerbeder]

The caps were replaced with caps of the same values, the only change made was that 85 degree caps were replaced with 105 degree caps, if they were available.

I believe that the power supply puts out 12, 5, and 48VDC, I don't specifically know the power, but it says it consumes 80W 110V on the back plate, so, somewhere between 1.66 and 16 amps, right?

-Parker

 

[Sceadwian]

I believe that the power supply puts out 12, 5, and 48VDC, I don't specifically know the power, but it says it consumes 80W 110V on the back plate, so, somewhere between 1.66 and 16 amps, right?

Are you serious? That's an entire order of magnitude difference in current output... And you don't know the power output for the various voltages? You're not even guessing now, you simply don't know. If you can't even state what the original supply was designed to supply as far as current goes, there's nothing anyone anywhere can do for you.

 

[parkerbeder]

Yep it is, I was just doing the math if all of those 80 watts were in 48v or if they were 5v. I obviously do not know the specific output for the voltages, it's not listed, and I don't have a schematic, lastly, it's not working correctly so I can't measure them. I'm confused I guess in what the current output would have to do with a theory on what could be wrong with this circuit. originally I was looking at a simple oscillation, a medium speed one. About one a second. Now, after replacing the caps, that period slowed down to 60 or maybe 120 seconds. Obviously this isn't a transformer or a fuse. I am only fishing for someone who has a firm grasp on theory who might be able to nail down what would cause an oscillation of this type. Now, when it powers up, it reads voltages that seem to be close to what is specified, but they drain down pretty quickly when connecting a voltmeter to them. This would typically be caused by a _____, is all i'm looking for, which mainly is being walked through for me by tvtech. I apologize if i have caused you any undue frustration.

-Parker