I’ve been having some inconsistencies with the braking and starting of my Universal I. Dave Seat was here about a month and a half ago and made some adjustments to the microswitches to prevent the hard hitting at the feed board I was having (and more importantly showed me how to make proper adjustments). Yesterday it was slamming a bit again so I adjusted the switch and everything ran picture perfect. This morning I went to run it and everything was fine for maybe the first 50 prints, then it started to hit again for the next 50 and then it decided to struggle to leave the feed board and hit hard.
It now will not leave the feed board without a push. What do I need to adjust/lubricate to try and get this more consistent? I saw this earlier post and was intrigued, but not enough to start opening a motor if I don’t have to!
“I have recently rebuilt a Uni-III Power and was perplexed when I could not satisfactorily adjust the “braking” of the carriage at either end of travel. I adjusted the clutch to book spec, checked the micro switches, contacts and rheostat, all were functioning properly. With no other known adjustment I turned my attention to the gear-motor where I removed the top cover (a 2 inch disc affixed with 3 screws) and found an adjusting nut just below the oil level. Given that the access hole was large enough for a socket and was overkill for an oiling hole I put a socket on the nut and turned 1 revolution clockwise. To my amazement the braking was now responsive and with a few more adjustments I can operate the press at about 65% speed with no hard slamming of the carriage.
My question is, has anybody else made this same adjustment and to what success? Is there any literature on this gear-motor anywhere?”
Thanks – Leslie
Are you talking about the relays/contactors on the control board? (A contactor is just a relay that’s used for switching high-current circuits such as motor control voltages) I was having an issue with those a few years ago on my press. There is a pair of contactors that are set up in a configuration called an H-bridge that switches the DC current to the carriage motor to make it go back and forth. Basically if you run the current one way through the motor it goes forwards, and if you run the current the other way (i.e. switch the wires) it runs in reverse. That’s how the carriage motor switches from forward (away from the feed board) to reverse). At the end of the run, it hits one of the microswitches which switches the H-bridge contactors and reverses the current.
I replaced the main contactors that control the carriage drive motor with new ones. I can dig up my notes about that if you end up wanting to try that. I bought new contactors on eBay, took out the control board and replaced them and that cleared up another problem I was having. The original contactors were sticking and not switching properly. This was causing my press to burn out fuses at the end of the press bed as the motor wanted to reverse, but the contactors were sticking and not letting it.
Replacing the contactors wasn’t hard – the tricky part was figuring out which modern contactors were compatible with the Uni I electronics. I can dig up my notes if you need them…
Actually, I promised Paul Moxon years ago that I would write this up for the Vanderblog. I suppose I really should do that! :-)
Thanks Erik. I’ll take a look more thoroughly tomorrow. I spoke with Fritz at NA Graphics today as well. He is very familiar with the history of my particular press. I definitely think that it has something to do with the press “warming up” as everything runs well when it is cold and it is only after the first 50-80 prints that I start to get the problems. He suggested checking the relays which I am going to do too. I’ll report back or contact you as I do more troubleshooting. Thanks all!
Hi Leslie –
Paul alerted me to your post – I have been neglecting to read the Vanderblog lately! I don’t know if I have a lot to add, but certainly try to make sure you have the clutch adjusted as best as you can. As you saw if you went back to see my old post, I was having trouble related to the clutch setting on my Uni I. When it has trouble leaving the feed board, is the carriage motor running, but the carriage not moving? That could be a similar problem to what I was having with the clutch. In our case, the screw that holds the clutch plate in was coming loose, and needed to be tightened and fixed in place with loctite. That fixed our problems of having to give the carriage a push to get it to leave the feed board. If you have questions on clutch adjustment, I’ll be happy to tell you what I did.
That being said, I still have to fiddle around with the microswitches now and again, and adjust the speed and braking as I’m running a job to keep the carriage completely happy. I’m now intrigued by the Uni III message and might go looking at the gear motor the next time I feel like getting oily…
I hope we haven’t left you hanging. I usually tell folks that they need to get on old guy ‘lectrician to look at it, but be sure to show him the schematic from the manual.
See if this older post and comments are applicable. https://vandercookpress.info/vanderblog/2009/02/universal-1-powered-carriage-drive-clutch-question/
I will email the author to see if he has any new insights.
Well, you are dealing with electrics that are half-a-century old. It is sort of like watching Outer Limits (I watch reruns pretty much every night; lot of goofy and entertaining electrics).
Grasp at any straw proffered here. I would. And, if you get a response that helps, donate a few bucks, well worth it.