1968 Modular Drive Problem - Won't Start, Need Help....

Dear All,

I don't usually seek help on forums but I think I can really benefit from the experts here.

I bought my 10EE earlier this year, worked great, very powerful. It had problems maintaining speed below 300rpm, which is an issue when I'm parting with HSS tool, but I managed.

A few weeks ago, it popped the 3A fuse. I was under the gun to finish a part so I jumped the fuse (I know I know....). That actually brought the machine back to life. I was half way through an aluminum part before it stopped working again.

Deservingly, now I have much bigger issues. When I turn on the power, it warms up, I can hear the fan go on, and after a while the machine lights turn on. Great.

When I hit the green lighted button, the Power Relay (PC) engages, but disengages as soon as I let go of the green button. So I took the time to learn the system and the troubleshooting begun:

1. Noticed the Field Loss Relay (FL) does not engage. I removed it, serviced it, made sure it works. It only took 0.5V to energize the coil to engage. Not sure if this is normal but it works well. Reinstalled back into machine, didn't fix the problem.

2. Followed and noticed that wire 18 on the FL coil connects to the contacts on the Anti Plugging Relay (AP). Removed AP, inspected, found a broken wire (a soft braided one soldered onto the coil switch). Happily replaced the wire, serviced the relay, made sure it works (took 36V to energize coil), reinstalled, didn't fix it.

3. Found 2 blown diodes in the module, both Rec 3. Replaced them with 1N4007, those are what I have on hand. Replaced both, ensured correct direction. Reinstalled, didn't fix the problem.

At this point, amongst the 50 other things I poked around with, I managed to get PC to engage and STAY engaged, for about 10 to 20 seconds, then it will disengage again. During this time, strangely, the safety interlock solenoid will drive the piston back and forth - extend, retract, extend, retract, at about 2 seconds intervals.

4. Checked the temperature sensor inside the tube enclosure, and it provides continuity between the 2 poles.

5. Checked voltage between terminals 5 and 18 on FL's coil. When I hit the green button, the voltage goes up to about 0.5V, and holds the PC engaged, but the voltage then drops to 0 after 10~20 seconds, and PC consequently disengages again.

Does anyone have any ideas what's happening here?

Thank you so much for taking the time and reading this boring post....

Howi

You Have no field voltage to the motor check that out you need at least 57 volts to the field of the motor the FL relay is a current relay no field voltage the relay will not energize field voltage is normally 120 volts dc. Start at the motor and check the field coils and make sure they are not burnt or shorted to the frame seeing how you blew the 3 amp fuse and jumped it.By jumping that fuse you may have burnt the field coils in the motor NOT good.

labeeman said:

You Have no field voltage to the motor check that out you need at least 57 volts to the field of the motor the FL relay is a current relay no field voltage the relay will not energize field voltage is normally 120 volts dc. Start at the motor and check the field coils and make sure they are not burnt or shorted to the frame seeing how you blew the 3 amp fuse and jumped it.By jumping that fuse you may have burnt the field coils in the motor NOT good.

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Thank you so much. I will check the coils tomorrow. Really appreciate it!

Wow I didn't know that the relays are current relays, thanks so much!!!

Howihowi said:

Thank you so much. I will check the coils tomorrow. Really appreciate it!

Wow I didn't know that the relays are current relays, thanks so much!!!

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Just the Field loss (FL) relay and one other the rest are voltage.

You might want to check the field voltage while you're in there - it's generated by the C3J so it's a common failure point.

Thank you guys. I jumped in there this morning and, without knowing exactly what I'm doing, I checked the voltage across A1/A2, S1/S2, F1/F2. This is what I found:

Machine STANDBY state: Power lever turned on, machine warmed up, work light came on, green lighted button came on.
A1/A2 = 0
S1/S2 = 0
F1/F2 = 0


Machine ON state: From STANDBY state, green lighted button is pressed once.
A1/A2 = 0
S1/S2 = 0
F1/F2 = Hard to explain, please watch this video:

17 8 3 Problem - YouTube

In the video, you can see that when the green lighted button is pressed, the machine turns on as it should. Then the voltage (F1/F2) starts to drop, eventually it shuts off, then turns back on, then off, and on. The machine was doing this entirely on its own.

Also in the end, you can see that the safety interlock extending and retracting correspondingly.

What do you guys think? Bad tube?

Thank you so much again for your time and help!!!

If it were mine I'd replace the tube since it's the most common failure point. Even if it doesn't fix the problem it's eliminated one likely cause and you'd end up with a spare tube to boot. NOS on eBay seems to got about $30-40, I even saw a pile of 8 going for $60 so they're not all that dear.

rke[pler said:

If it were mine I'd replace the tube since it's the most common failure point. Even if it doesn't fix the problem it's eliminated one likely cause and you'd end up with a spare tube to boot. NOS on eBay seems to got about $30-40, I even saw a pile of 8 going for $60 so they're not all that dear.

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Sounds good, I will definitely buy a couple on eBay today.

However, it could take a week before I receive the tubes. Do you think there could be anything else I can try during this time? I'd hate to wait a week and not do a thing....

Did You check your field in the motor what ohms did you get on F1/F2?

labeeman said:

Did You check your field in the motor what ohms did you get on F1/F2?

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I'm sorry, I thought you wanted me to check voltage, which I did in that video. I did not check the resistance. Should I check with the machine in OFF, STANDBY, or ON?

Off unplugged for safety you need to check to see if your fields are good in your motor.

labeeman said:

Off unplugged for safety you need to check to see if your fields are good in your motor.

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With the machine OFF, I checked the resistance at these 2 points. And it measured 69 Ohms. Not sure if this is how to check the fields....

That seems a little Low you need to check on the data plate of the motor to see what the field volts and amps are supposed to be. With nothing else in the circuit it should be 120 ohms you are reading some parallel stuff in the circuit which will lower the ohms.

labeeman said:

That seems a little Low you need to check on the data plate of the motor to see what the field volts and amps are supposed to be. With nothing else in the circuit it should be 120 ohms you are reading some parallel stuff in the circuit which will lower the ohms.

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Ya, I didn't think it was a good location either. It was hard to get to the motor with the blower fan in the way, I will try again tomorrow. Can't thank you enough for your support!

Sometimes you can get a smart phone in there to take a picture.

labeeman said:

Sometimes you can get a smart phone in there to take a picture.

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Will do, thank you again!

Good Morning!

So I took the time to trace the F1/F2 wires and disconnected them from the corresponding terminals. I made sure they are not hooked up to anything else.

I measured the resistance between them to be 82 Ohms. Still low compared to your 120, but I'm just glad to be getting something....

Howihowi said:

Good Morning!

So I took the time to trace the F1/F2 wires and disconnected them from the corresponding terminals. I made sure they are not hooked up to anything else.

I measured the resistance between them to be 82 Ohms. Still low compared to your 120, but I'm just glad to be getting something....

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That is why I wanted the volts and amps form the name plate to see if it was low. If it is low you have burnt fields and they need to be replaced NOT good news.

If you have this motor you are in the good. Now you need to work on why your field voltage is not good I would substitute the tube the first thing.

O
M
G

It's fixed!!!

Put in a new tube and it fired right up!!!

labeeman said:

If you have this motor you are in the good. Now you need to work on why your field voltage is not good I would substitute the tube the first thing.
View attachment 207128

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Yes! That's the motor I have! Thank you so much for your help the past few days labeeman. I've learned so much more about my machine thanks to you. I really really appreciate it.

I think by jumping the 3A fuse, I blew a bunch of small things including the diodes, mentioned above. In the end it was the C3J that was also blown and was holding everything down.

Can't thank you all enough. Thank you thank you!!!