Testing stepper on the bench

[mauro]

I'm still playing around with this V200 and now wanting to connect a wallbox to the TSR1 selection receiver.
Now, the TSR1 is missing the 25 transformer (T2) so we have a wall-o-matic type PS6-1Z power supply to use with the V-3WAD wallbox.
This juke is at a friend's place so I'd rather work on the stepper at home.
Can I just set up the TSR-1, power supply and wallbox on my work bench and try to make it step or does it have to be in the jukebox to work?
I would think I only need the 3 pieces but thought I'd ask in case I'm overlooking something.
Right now the stepper is dead and doesn't respond to the wallbox.
Thanks.

[robnyc]

You'll need a stepper tube (2D21 inTSR-1). Make sure the outboard power supply is connected to the chassis ground as it would if original. Connect the wallbox to the terminals or 3-pin plug as designed. It should at least step up.

Here is something I wrote a few years ago to answer typical stepper questions:

the first step is to determine whether the wallbox or stepper is at-fault.

Testing the 200 select wallbox is easy. Disconnect it from the machine. Connect you ohmmeter from the chassis ground screw and the -blue- signal screw. Then, with no buttons pressed, turn the wiper by hand and note that you see a low-no resistance connection at each rivet on the wafer as the arm passes over it.
Ideally there should not be more than a few ohms measured at any rivet, but the system is reasonably forgiving and even several dozen ohms will be OK IF the stepper itself is working well.

Stepper: First order of business is to make sure you have a good 2050 tube. Look at the top inside of the tube, in the area around the cathode (orange glow) you should see a deep violet aura when you touch the signal wire to chassis ground. Pale, sky blue indicate a weak tube.

Check the 100 ohm resistor on the tube plate circuit. Be sure that the large 5mfd capacitor in the 2050 plate circuit has been replaced.

Take a small flat blade screwdriver and use it to move the stepper wheels. They should easily snap back to their "home" positions from any point when released. A drop of light oil on the bearing shaft of each stepper may loosen them up, if not, the contact wafers will have to be remove and tarnish removed from the contacts with a non-abrasive polish. The wafer must then be realigned with the contact wiper when reassembled.

Gently press down on the edge of each stepper "clapper" to the point where the toggle is not touching either the wheel teeth nor the top of the slot. While holding it there gently move the toggle from side-to-side and be sure it instantly snaps back. These steppers are rated to be accurate at a pulse width of 1/100th of a second. Seeburg operates them at 1/25th so there is ample headroom, however all parts must be free moving.

When diagnosing the stepper is is important to note if the miscount occurs only in one stepper wheel -or both. Does it sometimes play a higher letter-number? this indicates that the wheels are gummy and not homing. Or does it always err on the low side by selecting a lower letter or number.

Beyond these tests and measures requires a bit more skill and some common sense -it is easy to make a mess of a stepper by tinkering. You'll need to assess your abilities to deal with a somewhat delicate electro-mechanical device, or turn it over to someone else. The good news is that once properly serviced, steppers are quite reliable and likely wont need attention for many years. I have nine old Seeburgs with a total of 93 V3W wallboxes and another 21 Rowe AMI wallboxes in two other places. While I'm not wild about still using steppers in 2014, if properly serviced they are quite reliable -even in heavy service.

Rob/NYC

[Ron Rich]

Rob,
Very well stated-- I have just a slight dis-agreement with it-- On the 2050 tube, maybe it's because of my poor color perception, but I have never been able to determine the "wellness" of that tube by color-- I judge it by the color of the top of the tube--If "clear", it's usually an un-used tube--darker the color the older (in service time) it is--
As for lubrication, I have found that a "safety solvent" sprayed on the contact wafer plates, followed by a shot of Deoxit-5, will sufficiently "clean" the plate, with out the need to dis-assemble it. To add to the above--The toggles MUST be clean--I use "safety solvent", then ONE drop of 20 w. oil should applied to both the anchor pin and the area the toggle slides on(see Seeburg Service Manual, for "oiling" instructions).
On the 100 ohm 2 Watt resistor, I change it to a 100 ohm, 1/2 watt resistor, just in case a wallbox happens to jam on a rivet. If that happens with the 2 watt unit in place, it generally will burn out a step coil--with the 1/2 watt, it will burn that first(hopefully )!
FYI-SOME, 200-160 wallboxes were equipped with an "anti-cheat" switch--can't re-call but if so equipped, and it is either ope, or closed at the wrong time, it will prevent the selection from being made (step-up oil won't function!).
Whatever you do, do NOT "force, bend,or,stretch" anything ---

Ron Rich

[robnyc]

"On the 100 ohm 2 Watt resistor, I change it to a 100 ohm, 1/2 watt resistor, just in case a wallbox happens to jam on a rivet"

-And we both know where you got that idea :-) Seriously though, it will burn the resistor IF the tube is still strong. Back when I still used those tubes, there were cases where a failing tube would self-ignite but not be strong enough or last long enough to do any damage.

That resistor is among a set of mods i do but omitted in that post. Here are a few pointers that have resulted from 32 years of love-hate with these little torment items.

For some inexplicable reason Seeburg routs the signal line into the credit unit. In some cases this will put a direct short across the signal line when the credit wheel advanced 4 stops. I cut this wire on all boxes (see red lines):

www.flickr.com/photos/90641375@N06/38768259991/in/dateposted-public/

Another, less troublesome is the anti-cheat contacts that reside on the left side of the keyboard:

www.flickr.com/photos/90641375@N06/23903595027/in/dateposted-public/
www.flickr.com/photos/90641375@N06/24895091298/in/dateposted-public/

There are actually two types, the other is an over-center switch with a link shaft to the treadle arm. this puts a significant extra load on the cam, I eliminate both.

From time-to-time a short will appear due to items getting into the keyboard. In some cases these short the "singles vs EP's" harness to the box ground and, thanks to the asinine way Seeburg designed it, this will lead to a dead short across the AC line blowing the fuse as the box attempts to cancel the credit -WTF! One of the items is a small piece of copper that acts as a cushion to reduce the noise when the buttons pop back.
It looks like this:
www.flickr.com/photos/90641375@N06/26252716849/in/dateposted-public/ A good shaking at various angles usually releases all detritus. I also add a fuse to each box and a relay to the signal line to prevent one box from bringing down the whole line.

There is more, but that is enough for now....

RobNYC

[mauro]

Guys,
I can't tell you how much I appreciate therse tips!!
I think the depth of knowledge on this board is a treasure and by sharing it we insure it's survival.
I have been playing with jukeboxes over 20 years now and it always amazes me how much I DON"T know.
I've rebuilt dozens of stepper but always had the jukebox with me for Testing, this time I won't have that privilege hence the need and question about bench testing.
Now remember the TSR1 uses the 2D21 tube and not the 2050.
I have read and noted your comments on the mods but would it be the same with the 2D21 tube?
Thanks again,
Mauro

[Ron Rich]

Hi Mauro,
IMHO, yes--same applies no mater which TSR is used. I did err, however, on the resistor--original (R-24)calls for a 1, not 2 watt resistor. Replacement 1/2 watt resistor should be the carbon, type--
Ron Rich

[mauro]

Ok great to know.
I'll most likely get on it next weekend.
I'll let you know how it turns out.
Cheers