Film-Tech Forum ARCHIVE: Potts Platter Fuse keeps blowing

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Posted by Mike Frese (Member # 4361) on 02-14-2010, 08:10 PM:

Potts Platter Model 35-3a

Was working fine for two shows today. When threading for the next show, the platter was not paying out.

Checked fuse and it was blown. Changed fuse and it blew right away when power switch was turned on. Disconnected all platter motors and replaced the fuse. It blew again and tripped the breaker.

A visual inspection of the variable transformer shows all wires to be secure.

Thanks
Thoughts?

Posted by Jeremy Weigel (Member # 4208) on 02-14-2010, 08:15 PM:

Did you also disconnect the variac?

Posted by Jack Ondracek (Member # 1466) on 02-14-2010, 08:15 PM:

Check the lights. It's not impossible one might have shorted. When you turned on the power, if the dancer arm was dropped to the bottom (platter motors off), then it takes out most of the system. Check the shutoff switch, it might have shattered (doubt it, but could be). Otherwise, the lights would be the only thing that would be energized with the arm at the bottom.

Posted by Mike Frese (Member # 4361) on 02-14-2010, 08:27 PM:

I did not disconnect the variac, but will try that.

Lights have not been working for a while, but I will try to see if they work.

Posted by Jeremy Weigel (Member # 4208) on 02-14-2010, 10:24 PM:

Isn't there a separate fuse for the lights or was that added on later models?

Posted by Mike Frese (Member # 4361) on 02-14-2010, 11:12 PM:

I found the problem. A black wire on the back side of the transformer (behind the distribution block) had become loose and was touching the transformer causing it to short.

I have begun to take the transformer out of the box that houses it but I am having a difficult time finding an allen wrench the right size. I will check tomorrow morning with the automotive store next door to me.

Lights on a seperate fuse.

Thanks for everyone's quick help. Thankfully this occurred on our slowest screen.

Posted by Joe Redifer (Member # 3) on 02-15-2010, 12:59 AM:

Maybe try metric allens, though from what I remember Strongs use The Queen's measurements.

Posted by Monte L Fullmer (Member # 2797) on 02-15-2010, 03:02 AM:

Nah...they're American Standard .. you need a 1/16" allen to loosen the two setscrews that are on the rotor collar to remove the pivot shaft from the variac. Best if you get a set of screwdriver, or "T" handle allens .. works great when doing variac work.

Posted by Louis Bornwasser (Member # 3063) on 02-15-2010, 08:08 AM:

That screw location that Monte mentions is counter-intuitive. It is on the other end of the variac. My first time, I fought this for an hour until I decided to "try all screws." Louis

Posted by Mike Frese (Member # 4361) on 02-15-2010, 02:19 PM:

Yep, the first screw I tried had me perplexed for a while until I was told to try the two screws on the rotoe collar. No problem then!

Unfortunately looks like the tranformer is shot.

Anyone have a used one they want to sell?

Posted by Mike Frese (Member # 4361) on 02-15-2010, 04:48 PM:

Final solution: I had a spare MUT that I was not using and took the transformer off of it.

Back up and running.

Thanks for everyone's help.