I have just acquired a series 1 Interact, in a little worse shape than I had hoped. The TNC 151 power supply is dead. Heidenhain says they will fix it, estimate is $100 - $2800 depending on what they find. Before I commit to that, I would like to test the servo drives which I obviously can't do from the control. If the drives are bad, I understand they are unrepairable, so then I move on to the complete control retrofit.

It looks like I can test the drives by energizing the axis release relay, then applying +/- 10 V on the drive inputs from a lab supply. Of course I would need to be careful since I have disabled about 100 safety devices this way. Is there anything else wrong with this test?

Yes, you can test them that way.

I energized the DC enable and the drive inhibit relays, then applied a few volts to the drive input, everything moves like it should. Very little current into the drive input as you would expect. If you try this and don't have a nice lab supply, a single D cell should do the trick - 1.5V is a reasonable feed rate. One polarity goes left, the other goes right etc. Also the stop switches still function because they kill power to the drives when hit.

Guess I'll send my 151B control into Chicago and see what the damage will be. Anybody got a spare power supply for one of these?

they will be good to you, even if they charge you the max. it beats the time/money of a retro.

they will be good to you, even if they charge you the max. it beats the time/money of a retro.
They were already good. I asked for help on the 151 and they said "we will have you talk to our Dinosaur guy, Rick" and he talked to me for a long time and gave me a bunch of useful information.

Tell Rick about this discussion group and actively encourage him to join us - the expertise needs to be tapped ! If he shows up we must make him very welcome.

Rick is the man

I had to bump the table around to get the thing more balanced (on the very tips of my lift forks....) and so I used a single "C" cell as the drive source. Works very well. If you are ever in this situation you have to energize the DC enable and Drive inhibit relays, then hit the drive input with the 1.5V from cell, works real nice - who need a stinkin' control! (Obligatory dislcaimer: don't do this unless you really know what you are doing and understand that lethal voltages are all over that thing!!!)