Since I need for my company a "reference" quality W19, there was no other way then to fully restore one. Well it was a lot of work, but I am happy I did so. For many German tubes, this is the best tester. I just take my W19, plug the right card on, and I know what I read on the tester is fully correct.

Dou you want to read more? A full report is here

Card Errors

Don't take this so serious... Card errors are normal with tube testers. Roll chart errors with the Hickok's are as normal as can be. Since old roll charts are now expensive, either NOS or used, these rrors will keep on following us. Anyway here are some of the errors I found myself with the Funke cards. Small directory here

Accuracy of FUNKE W19

As you can understand I wanted to know how good the accuracy of the W19 is, because I had fully restored it. Actually the one I have is now amazingly precise. So when you read 10.0, it is 10.0 and not 10.1 with this tester. This could only be achieved by re-calibrating the analog meter. Originally it was not so good, and had errors of a few percent depending on what scale, and what sensitivity. The main error was unlinearity. Read more