Ikegai 20N 5T spindle speed problem

[BKBridges]

I posted last time in the fanuc area, not noticing the special 5/5T zone...
Special...My Ikegai FX20N (1978) failed during a cycle due to bad brushes on the traverse motor. I replaced the brushes, and restarted the lathe only to find battery alarms on the memory boards. During ur trouble shooting we must have knocked the wimpy plastic battery holders a bit and they stopped working. Fixed that, re-entered the parameters, and everything came back... except for the Spindle speed control!. S40 in MDI gets full speed...any other command gets the same. Weve never had this issue before. Could it be the tachogenerator mysteriously failed at the same time the Servo motor did? Hard to believe... Anyone with any thoughts on this? Weve run this machine for the past 9 years without any major issues (other than the typical stuff...)
Bruce

[BKBridges]

checked the params again and 49, 45 and 50 were "wrong" so I changed them... No difference though. No alarms, MDI turns the spindle on and off with and M3 or M4, but it wont recognize an S number. Looks like the spindle is only running about 600rpm (not full tilt). When you input in MDI and hit start, the green light comes on and goes off, but nothing happens (spindle speed wise...)
Bruce

[Dan Fritz]

Give it a G97 in MDI first, then press START to be sure that you are not in constant surface speed.

Check to be sure parameter 00 bit # 5 (the 6th bit from the right) is a "1". That's the option parameter for constant surface speed control.

You should also have some switch inputs that tell the control which gear the headstock is in. If you only have one gear range, that's OK too, but most lathes have more than one gear range between the spindle motor and the chuck. The MAXIMUM spindle speed for each gear range is set in parameters 55 and 56 are used to set the maximum spindle speed in gear range 1 (when the motor is going at full RPM) . Parameters 57 and 58 are used to set the maximum spindle speed in gear 2. Parameters 59 and 60 are for gear range 3, and parameters 61 and 62 are used to set gear range 4.

You might have these parameters zeroed-out, or you might have a bad limit switch so the control doesn't know what gear range it's in.

[BKBridges]

Dan,
Thank You for your input! We will check out the G97 input. While we were floundering around we found the param 55 was incorrect, and when we fixed that, the machine now thinks everything is AOK... In handle mode you can adjust the spindle speed with the "knob" and the controller thinks its changing the spindle speed, but it doesnt. Before it didnt do anything with the handle knob... We did some measureing on the DSR board, and found a constatn 29VDC on the 52X input... No clue. When we looked further, we found the ChingaMuerto in the DSR thyristor pack... An Electrocuted mouse! We extracted the body (we are in the high desert and its hard to keep the little guys out), but no change in performance. I measured the "lollypop" capacitor thryristors in an act of desperation, and found that one of them was open (the other two measured 95ohms to ground)... Is there anything I can measure that would indicate the DSR or the board attached to it??
Bruce

[BKBridges]

Dan,
G97 didnt change anything re: operation. We checked the Params again and they are good... I yanked the "compact" DSR and am taking it to the local Fujitsu Fanuc reapair shop... Im hoping they find something wrong. I sure would like to retrofit the Ikegai, but Ive read too many horror stories too entertain the idea seriously. If anybody has retrofit one with new controls etc, Id sure like to talk to them!
Bruce