Power Supply Smoked

Electronics talk! Arduino UNO, Raspberry Pi and more
Post Reply
User avatar
Roberts_Clif
Reactions:
Posts: 552
Joined: March 25th, 2017, 8:17 am
Location: Washington
3D Printer(s): Hictop 3DP11/12

Power Supply Smoked

Post by Roberts_Clif » January 4th, 2019, 10:02 am

Moved from Hictop RepRap Prusa i3 / Hardware Modifications

I ask them what they wanted me to do with the non-functioning Power Supply, they said keep it not worth Return Shipment.
So I will put it on the shelf of electronics equipment to be looked at for Repair / Replacement Parts.

With two broken supplies of the same type should have enough parts to repair one at least.
Electronics Technician / Computer Programmer

GrueMaster
Reactions:
Posts: 369
Joined: March 15th, 2017, 8:46 pm
Location: Oregon
3D Printer(s): Hictop 3DP-17, Hictop CR-10S

Re: Power Supply Smoked

Post by GrueMaster » January 4th, 2019, 10:16 am

Probably just a few blown caps. I've seen that happen. Back in the Pentium III days, there was a cap vendor in China that had a year of bad quality output. Thousands of motherboards and power supplies died that year.

User avatar
Roberts_Clif
Reactions:
Posts: 552
Joined: March 25th, 2017, 8:17 am
Location: Washington
3D Printer(s): Hictop 3DP11/12

Re: Power Supply Smoked

Post by Roberts_Clif » January 4th, 2019, 1:14 pm

The Original power supply blew taking out both High Power 24N60CFD Mosfet.
Which in turn took out the 3watt bias resistors and a 1/4 watt resistor which I have no idea what value it was.
You can see in the photo that the left Mosfet left most leg has blown, and various resistors on the Photo.
Mosfets.jpg

Because of your are interest, opened the S-500-24 shown below.

S-500-24.jpg

Nothing is visually burnt measured the Fuse and Thermal fuse both in good shape.
Connected power and measured power threw the fuses to the pi filter, AC power arriving and measuring on the full wave rectifier B02.
Changed over to DC voltage Voltage on B02 rectifier measures 330VDC All high voltage caps are good still no output voltage.

Measure random spot to see where the voltage starts and stops. Opps! Whoa!!!! what happened power supply came to life.
Well that exciting and was very short lived, first it jumped into a powered on state now it is back to not working again.

Well the diagnostics are completed and verdict has been made the supply has a cold solder connection.

With the this new known information, completely dissembled the supply and removed the printed circuit board from case.
Then completely examined the board with no visual detection of where the cold solder joint is, all connections look good.

OK. Well at this point in time nothing to loose, only left with one choice, reverted to the shotgun method solder everything.
Connected the Weller PU120 soldering station, dragged out my .022in QQ-S-571 solder and began solder every connection.

Reassembling the Supply making sure that all insulation material is between the heat sinks and TO-3 packages.
Connected the power this is where I wish I had a variable AC supply then I could adjust the power up slowly.

I feel good this is going to work, Time to see if my labors worked or will there be a loud bang and a huge puff of smoke.

And the verdict is in the supply is running
Electronics Technician / Computer Programmer

User avatar
Roberts_Clif
Reactions:
Posts: 552
Joined: March 25th, 2017, 8:17 am
Location: Washington
3D Printer(s): Hictop 3DP11/12

Re: Power Supply Smoked

Post by Roberts_Clif » January 4th, 2019, 5:56 pm

GrueMaster wrote:
January 4th, 2019, 10:16 am
Probably just a few blown caps. I've seen that happen. Back in the Pentium III days, there was a cap vendor in China that had a year of bad quality output. Thousands of motherboards and power supplies died that year.
My First Power Supply blew the NTC Thermister, seeing as how it was paralleled with a standard fast blow fuse I simply bypassed it.
I know this is not normally a good ideal but the circuit has protection with its secondary a standard fast blow fuse.

Now with the passing of my S-480-24 power supply I can choose between the two NYC SD-15 that are inside the supply.
Although all the parts required to convert the 3DP11 - 12Volt 3D Printer to a 3DP12 - 24 volt 3D Printer are on hand.

Going back to the blown cap I was given a fairly new RCA 5.1 CH Home Theater System with Blu-ray Player (RTB10223).
The only thing that was wrong was a 20cent capacitor on the power on circuit.
In the Power on circuit a small voltage stored on a capacitor allows the power switch to send this voltage to a circuit to allow for power on.
This capacitor was under rated, the voltage being right on the edge caused it to blow (explode), replaced capacitor with larger volt capacitor fixed.
Anyway I digress but got a 20 cent Home Theater System now for 3 years.
Electronics Technician / Computer Programmer

Post Reply

Return to “Electronics”