Power feed help

[IRNMIKE]

Anyone know of a place that rebuilds power table feeds? I have the original X axis feed on my Lagun FTV2 and the feed rate selector quit working. It only runs in high speed now, which won't do. I opened it up and it has quite a bit of corrosion inside.
I'm hoping that someone refurbishes these, so I don't have to pay $500 for a new one.
Mike

[Thrud]

Mike

Search http://www.ThomasRegional.com for rebuild services or ask your Lagun rep.

[docsteve66]

Mike: I am not even conversent with the feed feed you have. But if it is just a adjustable speed motor (with brushes) the control circuit is probaly gone. Check for a defective triac (or quadrac). The ones I have worked on are very simple designs (electronicaly). If you get a schematic for the unit, and take it apart your self, most any TV/radio/electronics technician should have no problem repaing it for you- if they are interested at all.

Do you have a schematic?
Steve

[IRNMIKE]

I don't have a schematic, but the variable is just a rheostat type device. I considered replacing just that. The corrosion inside is concerning me though. It is the same basic housing as all the other Bridgeport knee mills use.
Thanks,Mike

[docsteve66]

OK !!! MIKE!

If its like the bridgeport stuff i may be able to help.

You have a jog button? Does it cahnge the speed?

Finaly some one mentions SOMETHING I may have some knowlege of . I am so Happy!!!!!
Steve

[IRNMIKE]

Yes, it has a jog button. It increases the feed rate when the unit is already running. I think it is a rapid traverse button to be more correct. It doesn't jog the motor.
Mike

[docsteve66]

Right on Mike: The jog button (I am guessing on your, know for sure on some) Just "shorts" (by passes) the Triac. If the speed increases a noticable, but small amount, the Triac is probably conducting all the time. May beshorted, lesser chance the control circuit is messed up in some way. If the Pot were bad (about all they can do is open) the Triac would probaly not "fire" (Trigger) and your speed would be very low. Its wourth a trip to radio shack and buy a replacement. Their supply is not extentsive. The Triac is buried way deep, underthe PC board, mounted on the case (for a heat sink). Get some heat sink compund as well. There are only three leads to the Triac. One lead is smaller than the others, there is also a dot on the case of the triac. Just be sure to get the wires back where they come from (proper order). Last one I worked on had been washed out (after disassembly) with engine de greaser. The degreaser caused pot to go bad. The shaft on the pot was longer than any standard pot shaft. Radio shack nor any local supplier even had the correct resistance pot. Made some mods to the circuit to compensate, welded and length on the shaft. found some bad joints (factory defect) that exlained why you had to kick or hit the contraption to make it work some times . The thing was a bitch to work on. No schematic so I did a hand over hand tracing and made my own. Schematic helps if you are electically skilled. I can get a copy but it is 30 miles miles to the owner. Let me know if yu really need it and give me time to get it.

The real problem becasue there were so many things to correct, was that I could not trouble shoot or even measure voltages becasue the thing had to be disassembled and could not be opeated until re assembled. I finally removed a knockout plug, extended the leads to PC board through that hole and finished up in short order. All to do over again the extending leads would be done first (these repair jobs always come back- even years later- because the labor would exceed the cost of a new unit. I just enjoy solving problems the first time).

REplace your Triac, its a small cost item. THe one I speak of had a "diac", the triac (and they look the same) gave lots more torque, smoother operation and cost less than five dollars. Let us know how you do (skills) with electronics and our answers can be better tailored to your problem.

Who is the manufacturer? Every one I have seen for years is Asian. all were "chinese copies" of each other- except the PC boards.
Steve
(edit comment: I mispoke when I called it a "jog" you are right it is rapid traverse. I used it as a "jog" when I borrowed use of the machine and just had that term fixed in my mind. Sorry about that!!)

[This message has been edited by docsteve66 (edited 12-12-2002).]