Re: [CAD_CAM_EDM_DRO] Help with Renishaw TP1 Touch Probe?

Steven,
I had to look at your picture just to work out which probe you had.
We don't see many TP1's which is why I am unfamiliar with its
innards. However on a general note you should not expect to see a
short circuit across the contacts. Anything less than 3300 ohms
should be treated as a closed contact. When new the contact
resistance may well be in the hundreds of ohms but as they get
older/used the contact resistance tends to increase. This is
especially so if they have lead a hard life. There are three sets of
contacts which are across DC AB and EF. All three must be seated to
give an indication across 4 and 5. we recommend a nominal current of
0.5ma for maximum contact life.
The LED is a separate circuit and would be driven directly by the
interface. 10ma will do nicely.
Regards
Bill Phillips

>I just bought a Renishaw TP1 Touch probe on ebay. Besides getting a
>box of accessories for a TP2 probe and the probe not working, it was a
>pretty good deal :-) But of course, it doesn't seem to work. Here is
>a picture for future reference of the probe with the shank removed:
>
>http://www.geocities.com/karmannelectric/Renishaw_TP1_Shank_Removed.jpg
>
>If I put my multimeter on Diode Check and across pins 1 and 3 (LED
>cathode and LED anode), the LED lights up. So far, so good. But
>there is no continuity between pins 4 and 5 (Probe circuit). Also, no
>continuity between points A and B, C and D, or E and F (labeled in the
>picture). Unless... I pull on the probe tip "just right". I can get
>the resistance down to a couple hundred ohms. So something must not
>be right. I tried adjusting the trigger force adjustment screw, no
>real difference. I can use some help getting it apart. I removed the
>Philips screw. The white stuff around the PCB is some sort of rubber
>like RTV or something. The PCB seems to be held in place by the shaft
>that holds the trigger force adjustment screw. I tried chucking this
>shaft up in a collet to see if it unscrews, and I don't think it does.
> Maybe the whole assembly pushes up out the top? There is a connector
>on the side, and the LED on the side. Maybe behind the label (the one
>around the LED) is a hidden screw?
>
>Thanks for your time,
>
>Steven Ciciora
>
>