Denford Software & Machines

Is there any way to get a scan of Wiring Diagrams A3 400 074-082 for my Senior 3C mill (TNC155B control) s/n 3C24037B please?

I managed to resolve my earlier E-stop problems (VFD was faulty and consequently opening the E-stop loop, so replaced the Jaguar Cub with an ABB drive) but after a few months OK have new probs with Z and cct diagrams would be a great help.

Thanks / Dave

Thanks very much for that, its a useful start

If its possible, when you have a chance, would it be possible to see the others that were on the plate please? - i.e. up to 082 ?

Many thanks / Dave

Sorry - I didn't realise the you meant a range of drawings - I thought it was the year or something



Keep an eye on downloads ...

Thanks very much, machine is up and running again (and sorry I didn't make it clearer about the drawings - I just quoted what was on the embossed plate).

The symptoms were that sometimes the Z quill wouldn't reference on startup (it would just drive to the e-stop limit switch), or would sometimes start oscillating in service (sometimes between the limit switches, and at a feed rate far greater than the control would seem to specify).

Having checked the switches, my prime suspect was an encoder failure (although unfortunately the encoders aren't shown on the circuit diagrams) and there was no easy way to get a scope on them; and by plugging my external handwheel into the TNC in lieu of the Z encoder I could prove the Z encoder input on the TNC seemed to be working OK. The command voltage into the Z servo amp seemed plausible ... and then I found the culprit. This excellent machine has two nested feedback loops - the conventional positional encoder to the Heidenhain TNC, but also a lower level velocity feedback from a tacho back to the ASR Servotron servo amp - and the Z motor's feedback tacho had an intermittent connection at the junction block inside the head.

Thanks again / Dave

Ah, that all brings back memories... I would always get the servo motors running from a 9v battery box 1st, then work on the position loop by plugging the control in. Sod's law would usually ensure that you got a run-away motor at each stage and would have to swap the command and tacho wires to the drive