Use of switched DC jack

I am attempting a repair of a large format scanner by Colortrac. The power supply has failed at the connection with the scanner. Whether a fault of the plug or the jack I cannot tell, as it has melted.

The power supply is an AC adapter from FSP Group, with a 120V AC input and rated output of 19V at 3.42A. The output plug fits jack with 2.1mm x 5.5mm inner and outer dimensions. The jack is panel mounted, and I believe was made by Schurter, as follows.

Couple of things:

  1. The jack is rated to 12V and it bothers me that the power supply is 19V. I’d like to find a jack that is rated to 19V or above, but can’t find something with exactly the same size. The mounting threads on the Schurter jack are M12.5 x 1.0. I have found connectors rated for more than 19V with M11 threads, and have considered using a shim washer with an M11 inside diameter to mount to the existing panel.

  2. The Schurter jack is a switched jack. The positive conductor from the power supply connects to the riveted center pin of the jack, and the negative connects to the switched contacts which are normally closed and open upon insertion of the power supply plug. What’s strange to me is that on the back side of the jack, the two negative contacts are fused together with solder. I don’t know if this was by design or came about because of the failure of the plug/jack. My suspicion is that it is by design, but I don’t understand why a switched jack would be used in this case.

Do you have any suggestions on what would be a good method to repair this connection? Should I worry about the voltage rating of the connector? If I replace with another connector, does it need to be switched, or would it be acceptable to substitute a non-switched connector?

Pictures attached for reference.

Thanks for any help or suggestions.


Your internal switch to that jack is functionally bypassed, you don’t need a replacement that has a switch, but the way it breaks out to a ring terminal makes me think they were using it as chassis ground.

If you replace it with a jack that doesn’t have the switch you might want to solder two wires to the sleeve connection and run a chassis ground to where it was going.

I’d be more concerned with the current than voltage since that power supply is rated above 3 Amps if that connecter is the 500mA rated Schurter part you linked.

Closest Items I’m seeing are Tensility Jacks that look like you would indeed need a washer due to hole diameter.
54-00151 Tensility International Corp | Connectors, Interconnects | DigiKey

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Thank you so much for the detailed reply and suggestions. Yes, the ring terminal you noticed was attached to the chassis of the scanner.

I’ll check out the jacks from Tensility.

I hadn’t thought about current being the culprit on the connection failure, but I believe you are on to something. From the manual the power requirements for the scanner are stated as follows:

Less than 40VA (scanning) 4.2VA (standby)

Since the power supply is 19V, the amperage would be 2.1 amps max, which is FAR MORE than the 500mA rating allowed by Schurter.

It is stunning to me that the manufacturer would have chosen this jack.

Thanks again so much for your help.


Voltage rating is for prevention of arcing.

As @Kristof_2649 mentions, current is the spec that when violated is the cause of melting.

While it may look like a standard model Schurter jack, it may be a customized version with higher ratings for the specific device.

I assume the scanner made it well past the warranty period. So the design engineers at Colortrac seem to have specced a suitable part for their product’s many design constraints (e.g. price, availability, lifetime, manufacturability, etc.).

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With the help of your great suggestions Kristof, I selected a Tensility 54-00063 jack (non-switched). This evening I made the repair, and the scanner appears to be back up and running.

In case someone else happens upon this thread, I repaired a Colortrac SmartLF Ci24 scanner using this jack. I ended up using a common washer to bridge between the new jack and the existing larger panel hole.

The Tensility jack is rated for 6.5 amps and 48 volts. Far in excess of actual applied amperage and voltage. I can rest easy knowing this jack can handle the power being applied to it.

Thanks again for the help.

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While it is possible that the jack may have been customized for this scanner, I did contact Schurter and they told me that they didn’t have a model having larger volt and amp ratings, and they did not offer as you did the suggestion it could have been a customized version. I know that’s not proof that the failed jack wasn’t a customized version, but it seems unlikely to me.

You are correct that the scanner made it through the warranty period, and then some. I purchased it in October 2010, so about 13 years. It has been used very lightly. I disagree that the design engineers at Colortrac specified in this case a suitable part for their product. The idea that a product is suitably designed if it makes it through the warranty period without failure is, to me, short sighted. When it comes to a power connection, and where the potential for heat and fire exist, I think the manufacturer should minimally use a connector rated for the application. The jack I ended up using cost between $2 and $3, about the same as the Schurter jack originally used.

When I asked my dealer and the manufacturer about repair or replacement of this lightly used scanner, all they could tell me was that the scanner was obsolete, no parts were available, and they offered to sell me a new scanner. All I can say is that if I ever have to purchase another scanner, I’d look at other alternatives before Colortrac.

But, I may not have to purchase another scanner, as this one appears to be back up and running for now, and I’m pleased about that!


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