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Is my psu dying?

Posted by Sardi 
Is my psu dying?
March 12, 2019 07:01AM
Lately I noticed that my leds on the X axis are flashing simultaneously with the red led on the hot bed.



They are connected directly to the psu, and the psu I am using is the same 550W psu I got with ormerod 4 years ago.
I disconnected them now cause its hard to be near it from all the blinking grinning smiley

I hope its the psu, and not the board :/
Re: Is my psu dying?
March 12, 2019 09:45AM
This style Power Supply is built with a thermal restrictive disc current limiter.
Could be this as they go out during normal use most likely nothing else is wrong with the power supply.
They experience all the initial start up power fluctuation and stress of power on's basically protecting the power supply from initial high current startups.
Taking this startup current wears on the component cracking them causing them to be have this intermittent failure.

NTC thermisters are used as ICLs (inrush current limiters) to protect circuits of electrical and electronic devices against inrush currents

This part is simple to replace though it requires the disassembly of the power supply and the removal of the NTC limiting Switch and replacement of a new NTC of same rating.

Determining it is bad is simple as most of the time they will have a distinctive crack in there package.

The NTC limiting Switch Looks like this.




On this supply it is labeled RT1 and is in series with a 6.3amp Fuse.




Edited 3 time(s). Last edit at 03/12/2019 09:49AM by Roberts_Clif.


Electronics Technician / Computer Programmer
Re: Is my psu dying?
March 12, 2019 10:09AM
Thanks for the detailed clarification smiling smiley

My psu is a pc psu and I am really not comfortable taking it a part, especially when I never soldered anything in my life.. First I will try to find another PSU just to confirm that it really is the PSU at fault.

Re: Is my psu dying?
March 12, 2019 12:35PM
It could be that your PSU is dying, but it's more likely that the screws in the VIN terminal block are no longer tight. If it's an Ormerod 1, also check the terminal block in the ATX PSU adapter.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Is my psu dying?
March 13, 2019 02:54AM
All the screws on both terminals were tight, but I think I might have found the culprit



This pin is a bit burned, could this be the source of my problem?
Re: Is my psu dying?
March 13, 2019 03:11AM
I suggest you check the soldering around that pin on the back of that connector too.

I replaced the PSU by a 12V LED/CCTV one, see [www.thingiverse.com].

Edited 1 time(s). Last edit at 03/13/2019 03:13AM by dc42.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Is my psu dying?
March 13, 2019 05:30AM
I actually have one of these laying around, 300W, 12V, 25A, its not fanless, and the fan is pretty noisy grinning smiley
Is a 300W psu really enough for Ormerod 1? Considering I got the printer with a 550W psu.



p.s. I did put "Ormerod 1 owner" in my signature, but for some reson my signature doesnt show :/
Re: Is my psu dying?
March 13, 2019 01:46PM
A 300W PSU is enough for a dual extruder Ormerod.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Is my psu dying?
March 28, 2019 01:05PM
So I had some time and done an inspection of wires and connectors.

I had some burns here, so I re-crimped all the wires and changed the connector.



The back of the ATX PSU adapter looks like this



Wires in the VIN terminals are all tight, nothing loose. The motherboard is all ok, I didnt see anything out of the ordinary.

What I did experience after all the fixes is a momentary drop in power (it just went down for a millisecond but didnt shut down), and once the printer just turned itself off during heating up.

The LEDs stil flicker when the red LED on the heat bed blinks.

Soooo .. could we blame the psu for this? Sadly I dont have any other ATX psu to rule out or confirm that.

EDIT: @DC42 - I am using your sensor kit 2 (or 3) with te IR board, and the LEDs on your board to not flicker, only those connected directly to the ATX psu.

Edited 3 time(s). Last edit at 03/28/2019 03:40PM by Sardi.
Re: Is my psu dying?
March 30, 2019 06:30AM
Right now it shut down again by itself. No msg on gcode console, just a popup about a communication error.
Re: Is my psu dying?
March 30, 2019 01:18PM
Quote
Sardi
Right now it shut down again by itself. No msg on gcode console, just a popup about a communication error.

There are two dummy load resistors on the ATX power interface board. Are they still in good condition?



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Is my psu dying?
March 31, 2019 10:36AM
Got to be honest, I really dont know what a dummy resistor is, but here is a photo of the atx adapter, so if those 1K guys are it, they look good to me.

Re: Is my psu dying?
March 31, 2019 11:21AM
They are the 22R and 30R resistors at the bottom. They look OK in the photo. OTOH, one of the pins on the white connector looks overheated, as you pointed out earlier.

Edited 2 time(s). Last edit at 03/31/2019 11:23AM by dc42.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Is my psu dying?
March 31, 2019 11:26AM
It does look like that, true. And the soldering on the back is ok. So maybe that is the issue here?
I just turned the printer on after a day of not printing, started heating the bed and hot end, and it shut down again. I didnt mention that when it shuts down, I must unplug the AC cord from the PSU in order to start it up again, I cant just pres 0/I on the PSU and start it up.
Re: Is my psu dying?
April 01, 2019 02:20AM
Time to get a new PSU I think. I used a Corsair modular 430W ATX PSU for a while, and it was significantly better than the original Alpine one.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Is my psu dying?
April 01, 2019 04:51AM
I placed an order for a new PSU, found a good deal for a LC 650W, down from 65e to 50e, going to pick it up today.

Thank you for helping me out Dave, cheers thumbs upsmiling smiley
Re: Is my psu dying?
April 01, 2019 11:23AM
Just to confirm, it was the PSU at fault. LEDs do not flicker any more.
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