1969 Wild Di10 - 1972 T2 combination

A few years ago I managed to find myself a Wild Di10 optical head, but without the control box. The Di10 was the first electro-optical distance measuring device Wild Heerbrugg produced and are now quite rare. After having found that head I have been searching for the control box, but to no avail. Then in February 2021 a complete set came onto the market here in the Netherlands on an on-line auction site. A few weeks later the set arrived in the collection.

Sadly enough it came without the adapter that is required to put it on top of an instrument, but luck was on my side as only a few weeks later, in the middle of March, a T2 with the original adapter was offered at the same auction site and once again it arrived in the collection not long after. These adapters are maybe even rarer than the Di10 itself, as over time the Di10s were replaced with more modern distance meters like the Di3S, Di4, and Di1000 in the collection.

The Di10 is remarkably complete, it came with a 1969 manual, which is partially original German and partially written in Dutch, most likely by an employee of the survey department where it has been used. That survey department was part of the city of Rotterdam as indicated by stickers on the instrument (see figure 2). Next to the manual also a reduction table booklet was present that was used to reduce the measured slope distances to the horizontal using the observed vertical angle.

It was therefore quite a surprise to find out that the T2 I acquired for this Di-10 did not show any readings in the vertical circle, but just a blank view, not even the micrometer could be seen. Initially I though this was a T2 without vertical circle, but those were named T210 and T211, while this one was actually named T2. As it did have the illumination mirror for the vertical circle I wondered if something was wrong with it.

Using bright illumination and checking the whole vertical range of the instrument, I did see at one location a very faint indication of a vertical circle. After removing the micrometer I found the prism that is behind it to be completely fogged up. I removed and cleaned, replaced it and re-adjusted its position and the micrometer itself as that did not show the finest intervals. Now the T2 is working properly again and slope distances can be reduced again.

In order to test the instrument I ordered an original power plug, which are still produced. Connecting the control box did move the voltmeter (see figure 7) and lit up the illumination behind the display (see figure 8), but sadly enough the instrument no longer produces a signal when aimed at a prism. There is a fair chance that it is just loose contact in the cables, so maybe a nice project for coming summer.