Film-Tech Forum ARCHIVE: Devry slows down when lamp is turned on

This is topic Devry slows down when lamp is turned on in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

To visit this topic, use this URL:
https://ft-forum.com/ft/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=011913

Posted by Jacob Delaney (Member # 8629) on 11-28-2015, 09:01 PM:

My Devry XD(2000) slows way down when I flip the lamp switch. Probably down to about 18 FPS or lower. What could possibly cause this? I rewired it myself not long ago and it's just simply wired to a bus bar where AC comes in and splits to the motor and lamp. No modern controls or anything like that. Just four wires going to some switches for the lamp and motor.

Could I be overloading the power outlet? I don't notice any other lights dimming, just the usual flicker when I turn it on. I'm using the same 1200w incandescent lamp as before and never had any problems.

Posted by Sam D. Chavez (Member # 1841) on 11-29-2015, 12:36 AM:

Pretty basic troubleshooting here. Take a Voltmeter and check the outlet before and after, under load, lamp on, etc. Also check voltage across the motor itself.

Posted by Monte L Fullmer (Member # 2797) on 11-29-2015, 02:14 AM:

Could be that the motor is doing some serious current draw from within-like bearings, winding, et.al., is getting tired, or the DeVry is having mechanical resistance issues to make the motor work harder, which will pull more current from the buss where the demand is greater with the motor than the lamp.

Posted by Jim Cassedy (Member # 4115) on 11-29-2015, 10:12 AM:

What size (wire gauge) power cord are you using.
I fixed a similar problem on an old Simplex portable and the problem
simply turned out to be that they were using an 'under-gauge' power cord
for the amount of current draw the machine needed.

It was several years ago, but I think I made them a new power cord out of
AWG 12 rubber-covered cable with heavy duty plug & socket on each end,
and that solved the problem.

You said you had re-wired the projector. Did you use heavy enough wire?

As Sam said- checking with a voltmeter and an ammeter, if you have one.
would really be a good place to start your troubleshooting.

Posted by Jacob Delaney (Member # 8629) on 11-29-2015, 03:19 PM:

I don't see any ID on the power cord but I think it's 14 AWG. I don't remember what I rewired it with but it's much bigger than the thin rotten stuff it had in there. I just measured the power outlet at 121v and then with the projector running with no film at 119v and then again with the lamp on at 113/4v. I haven't tried it loaded yet or measured the motor.

Posted by Steve Matz (Member # 1890) on 11-29-2015, 04:22 PM:

Might be a Bum Toggle switch,simple SPST one. Pretty easy to find...

Posted by Jacob Delaney (Member # 8629) on 11-29-2015, 04:45 PM:

I didn't think about the switch being bad. It used to be wired so that the lamp and fan would only come on if the motor switch was on but I now have it wired so the fan is always on and the lamp and motor switches are separated.

I just sprayed some contact cleaner on them to see if that would change anything.
Here's what the panel on mine looks like:

Posted by Sean Weitzel (Member # 244) on 11-30-2015, 11:31 PM:

You've got a lot going on there with that control box and what not. If I was in your shoes I'd wire up AC bypassing everything except the motor and the lamp and see how it all reacts. Then start working backwards. I suspect you have one or more high resistance connections between the line cord, the control box and the rest of the projector. I started with a DeVry XD 20 years ago that had its share of gremlins. You will figure it out.

Posted by Jacob Delaney (Member # 8629) on 04-23-2016, 05:46 PM:

Ok so I decided to revisit this again and I wired up the lamp to a power cord bypassing the whole projector and yet again when I turn on the lamp with the projector running it slows way down... So this must something to do with the power here because it's draining the whole power from the garage when it's on by over 6 volts.

Posted by Kenneth Wuepper (Member # 1174) on 04-23-2016, 08:25 PM:

Perhaps there is a poor connection in the Ground Fault Circuit Interrupter.

Posted by Jonathan Wood (Member # 4614) on 04-24-2016, 08:11 AM:

Can you power the lamp and motor from separate ring mains? The lamp from your garage and take a separate feed from say your kitchen ? If still same problem then you have some resistance somewhere in the machine that's causing the problem .

Posted by Tony Bandiera Jr (Member # 2365) on 04-24-2016, 11:12 AM:

quote: Jacob Delaney
...So this must something to do with the power here because it's draining the whole power from the garage when it's on by over 6 volts.

You need to get an electrician out there ASAP to check the wiring to your garage. You have a bad connection somewhere which can heat up enough to start a fire. (Or worse, a bad neutral which can cause enough voltage imbalance to overvolt another circuit causing other things to burn up.) Don't put this off..

quote: Jonathan Wood
Can you power the lamp and motor from separate ring mains? The lamp from your garage and take a separate feed from say your kitchen ? If still same problem then you have some resistance somewhere in the machine that's causing the problem .

The machine is most definitely not the problem, since the voltage to his garage drops 6 volts under the load of the projector. That is a very good suggestion however.

Posted by Rick Raskin (Member # 1561) on 04-24-2016, 03:46 PM:

Is your garage detached? If so how far is it from the power entry to your house. Even if it isn't detached I suspect the feeder to your garage is undersized for supporting your projector.

If the feeder to your garage is underground you're probably cooking more than a few worms. [evil]