Timothy Jones
Plastic
- Joined
- May 11, 2007
- Location
- Central Massachusetts
I've decided to tackle the bull by the horns and come up with solutions for several components on the 10ee that I've seen fail. I have a tube type machine from about 1972 (not a WIAD). My list of what fails (based on experience) are the following:
1. Contactors and relays in the starter compartment
2. C16J thyristor tubes
3. In the spindle module: The rectifier diodes and in general the soldering which can have cold joints. I've not seen one fail, but I suspect the selenium suppressors may fail with age. Also the potentiometers can go out of spec or just fail.
4. The speed control potentiometer
Going down this list, I don't see much of a problem with the contactors and relays. There are enough equivalent components out there that replacing one is probably not so hard. They are basically mechanical and there is also always a possibility of actually fixing one. The C16J tubes are a different story. If you can find one, the current asking price seems to be exhorbitant. As for the spindle modules, I know from personal experience that they can lead you around the barn and back. I kind of like Monarch's advice of keeping a spare handy. I suppose Monarch might be able to sell you one, but I'd hate to contemplate the cost. Lastly the speed pot. That is real problem. It is 2 gang with each half being non-linear. Basically there is no replacement.
You might ask why not just go with a VFD or modern DC drive like so many others. My answer is that I think the tube drive is way cool. I love the purple glow. I want to keep my machine original (or at least in the spirit of original). There may be more practical reasons also. Doing a conversion is expensive and time consuming. I can run my lathe direct drive (no back gear) at 10 rpm with smooth unstoppable torque. I don't know, can a VFD do that? The bottom line is that I think Monarch did an excellent job with that drive and I don't want to change it with a lot of work for something less. I'm sure there are others of you out there who also want to keep your lathe unmodified but are running up against the brick wall of irreplaceable parts.
So I'm starting this thread to cover a project to first create a modern SCR based drop in (affordable) replacement for the C16J, and second to create an (again affordable) replacement for the spindle module. (If this works, I'll leave the speed control pot for a different thread). I think some people have already suggested the SCR idea but I'm not sure anybody has actually tried it.
1. Contactors and relays in the starter compartment
2. C16J thyristor tubes
3. In the spindle module: The rectifier diodes and in general the soldering which can have cold joints. I've not seen one fail, but I suspect the selenium suppressors may fail with age. Also the potentiometers can go out of spec or just fail.
4. The speed control potentiometer
Going down this list, I don't see much of a problem with the contactors and relays. There are enough equivalent components out there that replacing one is probably not so hard. They are basically mechanical and there is also always a possibility of actually fixing one. The C16J tubes are a different story. If you can find one, the current asking price seems to be exhorbitant. As for the spindle modules, I know from personal experience that they can lead you around the barn and back. I kind of like Monarch's advice of keeping a spare handy. I suppose Monarch might be able to sell you one, but I'd hate to contemplate the cost. Lastly the speed pot. That is real problem. It is 2 gang with each half being non-linear. Basically there is no replacement.
You might ask why not just go with a VFD or modern DC drive like so many others. My answer is that I think the tube drive is way cool. I love the purple glow. I want to keep my machine original (or at least in the spirit of original). There may be more practical reasons also. Doing a conversion is expensive and time consuming. I can run my lathe direct drive (no back gear) at 10 rpm with smooth unstoppable torque. I don't know, can a VFD do that? The bottom line is that I think Monarch did an excellent job with that drive and I don't want to change it with a lot of work for something less. I'm sure there are others of you out there who also want to keep your lathe unmodified but are running up against the brick wall of irreplaceable parts.
So I'm starting this thread to cover a project to first create a modern SCR based drop in (affordable) replacement for the C16J, and second to create an (again affordable) replacement for the spindle module. (If this works, I'll leave the speed control pot for a different thread). I think some people have already suggested the SCR idea but I'm not sure anybody has actually tried it.