DCU 600 – Error: 026

Isn’t it annoying, you are running a turbo molecular pump worth thousand of dollars and it fails to operate!? In our lab we use several TMH/TMU 1600 C pumps, two of them controlled by the (more or less) modern DC 600 controller unit. Exactly this unit showed us an error message, namely Error 026. Here is how we fixed it.

The error 026 is usually caused by an overheated TC 600 unit, which is directly mounted to the pump. In our case, this unit wasn’t hot at all. Unfortunately, the error didn’t disappear by resetting it as described by the manual. The next thing you usually do after such a problem appears is to contact the customer service. We did of course, hoping for the best. The friendly service of Pfeiffer Korea directly told us, that we need to replace the TC 600 controller unit, which is worth 1000$. Great, this might be no money for a big company, but for a small research group with little funding it is quite some money. The good thing about broken equipment is, that it’s already broken. From our observations we assumed, that there must be an issue with the temperature measurement, so we disassembled the TC 600 controller.

Attention: Electrical shock hazard! If warrenty still applies, contact the customer service! Disconnect any electrical connection prior to disassembly!

This is what our board looked like:TC600-board

This pretty much looks like corrosion (left side of the board), doesn’t it! Of course, corrosion can cause such a problem. Typical temperature ICs determine temperature by measuring a resistance. A leaking current can influence the resistance measurement and therefore distort the temperature determination. Even though the design of the TC 600 controller is pretty nice, it is not meant to be operated under humid conditions. This is quite a problem in korean summer, especially when your air condition fails frequently. Since the unit is water cooled from the back side, there surely is condensation inside the box.

So did cleaning help? We decided to give it a try, since we could only save (government) money at that point. After removing as much of the corrosion as possible (We used a wet Q-tip to remove most of it), we reassembled the system, and indeed the error was gone (see picture below). This is how 3h of work can sometimes save you a 1000$, if you know the reason for your problem.

After the board was cleaned, the error was removed and the pump worked again.

I hope this post might help others to fix the error, if similar conditions apply to your operation environment. Make sure you always handle electronics with care and use gently cleaning solvents for the electronics. Avoid aggressive solvents like acetone. All actions are taken at own risk, as usual!


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