Seeburg 3W1 wallbox selecting wrong record

Rob-NYC wrote:On both latter and number clappers there are two sets of contacts. The innermost sets on both letter and number charge the hold magnet. The outermost one on the letter clapper charges the transfer relay. The outermost on the number clapper charges Timing relay#1.

First pulse arrives and both letter clapper and transfer relay pull in. During the second pulse the roller contacts on the letter wheel transfer from the bottom contact to the top.

--There must be no chattering of either the hold magnet or the transfer relay while letter pulses are active.

At the transfer interval between letters and numbers the transfer relay falls out, the number clapper begins to operate and this keeps the charge to the hold magnet and now pulls in Timing relay #1 which in-turn pulls in # 2.

Again, NO chattering of anything other than the active clapper.

Once the last number pulse ends timing relay #1 falls out and a fraction of a second #2 falls out. This combination produces the write-in interval and initiates scan. After W-I the wheels are held for a fraction of a second by the hold magnet and then allowed to home.

Rob does this explanation also apply to my remote control stepper unit RCSU2 on my TSU3 control unit in my AY160?

Either way thanks for taking the time for writing that description.

Gordon it the two timing relays are not pulling in during action in the number clapper that is caused by the outermost contacts on top of the clapper being misadjusted.

Remember we went over that sequence. The innermost contacts on the clappers charge the hold magnet. The outermost charge the relays next to them.

Have you done tests on the wallbox using a 28 volt bulb between the power input to the box and the signal line? That is connect between green (25vac) and blue (sig) wires. and checked for normal pulsing corresponding to the letter/number selected?

I'm sorry you are having this much trouble here. Steppers can be a bitch until you understand their operation thoroughly. Then they become a mere PITA .

Rob

SteveFury wrote:Rob does this explanation also apply to my remote control stepper unit RCSU2 on my TSU3 control unit in my AY160?

Either way thanks for taking the time for writing that description.

Steve, this applies to all of the Seeburg steppers right up through the solidstate era. Aside from transistors replacing a tube, only the voltages and polarity changed.

Rob

EDIT: I should add that on later steppers at least from LPC-on one set of contacts on the timing relays is eliminated. This results in the scan coil pulling in and and the mech starting to scan while the numbers are still arriving as opposed to waiting for the entire sequence.


It made sense on LPC-Electra in that it sped up the select-scan-play time and I did mod a few of my old machines in this manner -mainly though to get rid of another set of contacts.

Hi Rob,
Is the number clapper the 'group step relay'? (On the right looking from the top)

The stepper is now getting the juke to scan about half the time (which is promising).

I think the problem is with the group step relay ratchet not working all the time. I think I have adjusted it while cleaning.

Now when it does scan it always plays the correct number, but never the correct letter.

For example, if I select G3, the juke plays D3, or if I select K 8, the juke plays G8 etc.

If I can get it to start the juke scanning every time, I can then work on why it selects the wrong songs.

I'll keep trying.

Thanks and regards

Gordon

Yes, the letter stepper- is the one close to the two timing relays. The contacts that charge the timing relays are the small ones on the number clapper that are nearest to those relays.

Also, those light contacts on the letter/number clappers can be a bit tricky in that if you set the top contact to have too much downward force it can prevent the clapper from moving up all the way between pulses. I set them with just enough force to close the contacts with a tiny bit of overtravel.

Rob

Hi Rob,

Thanks for taking the time to respond.

I am still confused.

Can you please tell me the purpose of the Unit Step Relay (many contact points for the ratchet) and the Group Step Relay (only 5 contact points)?

I think the unit step relay may be my problem as I believe the release dog is not holding the ratchet on every pulse.

Thanks again, Regards

Gordon....

The confusion stems from a difference in terminology.

There are two stepping switches:

Letter & Number.

The "group" term is a holdover from an earlier system.

On these systems the pulse counts from letters and number directly relate to a specific letter/number position of a selection.

The Letter stepper should have 20 wires on it's rivets. Number stepper should have 8 if for a 160 select or 10 for a 200 select. BTW: The 160 steppers are easily converted to 200 by severing the jumper that connects the 8-9-0 and running separate wires to the Jones plug for the 9 & 0.

If the hold-release dogs are not holding the stepper gear properly they may have gummy old oil in them, their locknut may be too tight or the the stepper coil/clapper may not be pushing the gear far enough to allow enough overtravel and allow the dog to fall into the gear.

This can be tricky to see but wedging the hold magnet down and pressing down on the clapper (do not touch the pawl or the small contacts) you should be able to examine how much overtravel, if any, is being allowed. This is adjusted by loosening the two screws that hold that coil/clapper and lowering it somewhat.

I usually move them down to the limit of the screw holes (if they aren't already) to allow maximum overtravel. This also makes sure that the coil stays level.

Rob

Rob, Gordo,
I have seen some steppers where the coils were set too low--this causes undo "back pressure, on the "dogs" themselves, the "posts" the dogs ride on, and the gear teeth. I have seen a few cases where this causes the dogs to "flip-up", and not hold the tooth---I set them all (either type dogs), for "over-travel" with a .15 feeler gauge. Ron Rich

Hi Ron and Rob,

I have made progress!

The wallbox now gets the jukebox to scan with every selection.

It also selects the correct NUMBER selected every time.

However, it only selects the LETTERS J and K.

If I select A,B,C, D etc it scans until it reaches the letters J or K and then stops at the correct number, and plays.

I'm getting close, however, I am away for a few days and won't be able to look at it until next week.

Thanks for your continued advice.

Regards

Gordon...

Hi,

PROGRESS!!!!

The wallbox is now working perfectly.

I went back to the start and rechecked everything. I think the problem ended up being the 'Dogs and Step Relay Magnet' being very slightly too tight.

Once I got these correct (and working), the stepper was still missing 1 count as it cycled. I traced it back to a bad solder in one of the rivets in the wallbox.

I am so pleased.

Thanks especially to Rob and Ron for staying with me on this. I would never have found the problem without your advice.

Thanks again,

Kind Regards

Gordon..

Hi Gordon,
You are more then welcome--thanks for posting the "final solution"--
Ron Rich

Gordon, I'm glad we were able to help you. This is THE time of year to own a jukebox!

Rob

I am having the same problem. I have replaced all caps, and resistor 4 at the 2050 anode.

After fixing a clipped 150v supply wire I got the 3W1 to finally trigger the 2050 tube. The selections were mostly ignored other than an occasional lucky letter/number combination. I removed the selector contact plates and noticed that they were very dirty. I sprayed both sides with contact cleaner and lightly rubbed them with 0000 steel wool. After reassembly the jukebox played a record every time a selection was made at the 3W1, unfortunately only the lower letters and numbers play the correct record. By the time you get to K it is playing 1 early, ex. Selecting K1 plays J10. Is this a problem at the Seeburg 100G or the 3W1? Could it be that I need to adjust the selector contact plates? I noticed there was a little play in the holes when remounting them.

Thanks

-Tony

Yes, Tony,
That's why they are "adjustable" --I sure would NOT use ANY, "steel wool" anywhere near any electro/mechanical device !!
Ron Rich

Ah, now we are getting into the true "joy" of stepper repair...and why folks down on Tenth Ave often dumped them on me.

Missed counting of higher pulse counts can result from:

1) Dirty, misadjusted wallbox wafer contacts. Broken wires at the contact wafer. First, make sure the box produces the correct count.

2) Stepper springs on the clapper getting weak thus not pulling the clapper back in time for the next pulse. There is no test for this beyond holding the clapper slightly down so that it is free to move and checking ease of movement of the clapper. Problems here will typically affect only one stepper switch of the two. There are actual gram/Oz measurements but I can't find them here. Ron probably has them

3) Gummy oil or dirt on the clapper that prevents it from shifting back quickly enough to engage the stepper gear tooth. Test as above.

4) Inadequate downward overtravel of the clapper. Hold the reset magnet down and carefully press down on the clapper in question to advance it one step at a time. Closely examine how the ratchet engages the gear to hold it during the upstroke. There should be a slight amount of overtravel and back up till the ratchet dog engages. This will normally be correct from the factory, but if the stepper has been tampered with the overtravel may have been set based on the lower teeth. As this gap gets smaller due to wear as the gear position (letters or number) go higher the gap may no longer be adequate to allow the dog to catch.

5) Ratchet dogs gummy due to old or wrong oil being applied. When moved they should instantly snap back.

6) Electrical. If a tube is used it should glow purple around the cathode during conduction. Light blue indicates weak emission. This will sometimes become more pronounced during long pulse trains. I'll spare you the details as why this happens, but it is one of the reasons why a tube may work in trip but not be accurate in stepper (and why I don't use them). --Always have at least one known-good tube as spare for test.--

6a) If there is a resistor in the plate ckt (seeburg steppers) check it for accuracy. These take a big hit due to the pulsed nature of conduction. Wirewound won't have this problem but I prefer to use a carbon ½ w so as to act as a fuse and protect the coils. Every year or so I replace that resistor as they do change in value in this service.

7) If there is a capacitor in the plate ckt as with Seeburg, it -must- be accurate. In a 5mfd, going just one mfd higher or lower causes miscounting about 10% of the time. I have long used mylar caps in this service and even after 20+ years of heavy service they are still as rated.

I have previously mentioned the backlash problem due to gear wear. typically this causes the wiper contact to touch two rivets at once, but depending on how the wafer is positioned a minute shift can cause it to contact only the lower rivet. When reassembling I connect continuity tester to the center terminal and while holding down the reset (butterfly) I advance the stepper wheel one notch and look to good contact at only the correct contact. At certain positions of travel a visual is possible too.

The rest magnet hold capacitor should keep the magnet energized till write-in is completed and scan starts.

As always, make sure everything is moving freely and not dirty.

I know this sounds like a lot to check and do, but most of these are one-time. I have steppers in commercial service for well over 20 years (oldest since Oct 1989) and other than cleaning the wafer rivets every 5-7 years and occasional contact point checks actual problems are rare. In home use you'll probably never revisit any of this once done right.

Rob