Seeburg 3W1 wallbox selecting wrong record

Hi,

I am installing a 3W1 wallbox into my Seeburg C.

It has a WSR5-L6 installed.

The Electrical Selector is working fine.

My problem is that when I select a record from the wallbox, the record it selects is usually 1 or 2 numbers off.

That is, if I select record C5 it generally plays record C4 or C3.

I have replaced the 5uf 300V cap and also a new 2050 tube. I have cleaned and lubed the step relays and polished all the contacts. The caps all appear OK. Wiring appears good.

I have also substituted another wallbox, however it has the same problem. So, I assume the problem lies in the stepper.

I must be missing something. Can anyone please advise where I need to check next?

Very much appreciated.

Kind Regards

Gordon...

Gordon,
That's the sign of stepper problems--did you replace the 300mf cap, and all small ones? Also, check resistor values--Also, can be a "mechanical" stepper problem--
If all's OK, one, or more contacts, are miss-adjusted. Ron Rich

Thanks Ron,

I checked the caps and replaced a couple, but for the little extra time and cost, I think I will replace them all.

I'll let you know if it improves.

Regards

Gordon.

Gordon, what did you use to replace the 5mfd cap? In my experience this one has to be within 10-12% and most electrolytic caps are often outside this value. Can you test capacitance?

If the error is occurring only on a letter or number stepper switch, look for sticky components associated with that stepper. Check that the holding dogs are totally free and not at all gummy. Similarly, check the stepper pawl for free action. I've had a couple of instances where the little spring that pulls the pawl back between pulses had gone slightly weak.

Check the 100 ohm resistor in the 2050 plate circuit and be sure that the tube glows only violet when it conducts. A thyratron tube trending weak --should-- affect letters and numbers equally, but at times one will err and the other will appear accurate. One of the little joys that made me get rid of tubes in the selection system.

Make sure there is adequate overtravel on the stepper gear (to be sure it gets caught by the dog) and make sure the coil is not crooked. You'd be surprised at what idiots do to these things while "tinkering" -well, maybe not too surprised.

I'm not a fan of stepping switches, but they can be kept running, probably forever, as opposed to LSI failures.

Rob/NYC

Rob,
You have now "crossed the line", into my domain ! You used to live with "Geppettoe's", and now you have joined me in the land of "Idiots". Welcome to my world !! Ron Rich

...A well populated land it is...

Rob

Hi,

I went to my local electronic store to purchase the caps for the stepper.

He was unable to supply all of the caps, so I took what I could get and started by installing 2 new caps. The manual says the caps should be .05 mfd 200v Condenser. The shop sold me .047 630V saying these will sustitute.

These are the 2 caps between the 'Timing Relay #1 and #2.

However, the stepper is now worse and selects records at random. Something is wrong.

I also found that the'lug' on the 500 solenoid for the 'Timing Relay #2, is loose. It still appears to work and is still attached to the wire in the solenoid. I think when I attached the cap, it heated up the solder and loosened the lug from the solenoid. Could this cause my problem?

To answer Rob's question, the 2050 is a nice violet color and the stepper pawl and holding dogs appear fine.

Any advice appreciated.

Regards

Gordon.

Gordon, the caps they sold are fine for the purpose. But you didn't mention anything about the 5mfd.

It is possible that you jarred some contacts out of adjustment while replacing caps. Often happens when working in less than ideal circumstances.

I think a review of stepper operation may help nail this down.

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.

Hopefully you have the wallbox right at the selection receiver so as to make observation easier.

When I can operate a stepper right at it with a wallbox I usually use "V0" for test.

When I have to test remotely I use "U9" this will help to tell me if possibly the stepper is transferring the pulse train too soon and thus some letter are piling onto the number wheel.

So take a look and let us know "wassup".

Rob

Hi,

Thanks for sticking with me on this.

I think you will be correct in that I knocked a contact out of adjustment while replacing the caps. I will spend some time and check them all again.

Rob, I don't know how to check capacitance, all I have is a basic amp meter.

I obtained a replacement 5mfd cap from a reputable person in the US. He sent me a Temco ID RC0048, round motor run cap, 370-440V, 5uf +/- 5%.

Ron, Unfortunately I am unable to locate the electrolytic caps in Australia (25mfd 50V and 300mfd 50V) so I will need to source them from the USA.

I will closely moniter the actions that you recommend and see how it goes.

Thanks for taking the time to respond.

Regards

Gordon.

Gordon, the 5mfd sounds Ok. For my own machines I use 5, 1mfd mylar caps.

As for the 300@50v this does not have to be replaced as long as the hold magnet isn't chattering and holds the stepper wheels a fraction of a second after write-in. Several of my location machines still have the original. Same with the 25mfd. Mallory made good caps.

In a sense, the circuit is self-testing with regard to these caps. Both excessive leakage and/or loss of capacitance will be obvious in the mechanical operation.

Rob

Hi Gordon,
Re: the "25x50" and the "300x50"--they can not be located anywhere, I don't think--as those values are no longer "made"--However replacements are ! These are listed as 22uf x 50, and 330uf x 50, which work "just fine". Ron Rich

Hi Ron & Rob,

I rechecked all the contacts and they required some very slight adjustment.

I followed Rob's advice the best I can and the stepper appears to be operating in the correct sequence. The clappers only move in-line with the 2050 tube. Is there a way to count the stepper clappers to check what numbers it is reading from the wallbox?

What happens now is the wallbox often selects one or two numbers off.

Selections like A1, B1, C1, D1 and E1, nearly always select correctly. If I select numbers 1-5 they are generally better, however, after number 5 it gets a bit random.

Lower numbers and letters appear to be more accurate. Higher numbers and letters get very random.

For example if I select letter K and it plays up to 5 records off or (sometimes) anything it feels like.

I am getting closer. Could this be bad caps? I have ordered the new caps today. or should I recheck the contact adjustments again?

Appreciate your time.

Regards

Gordon.

Gordon, what you describe is usually caused by:

Failing 2050.

Out of range 100 ohm resistor in 2050 plate circuit.

Out of range 5mfd cap.

Sticky pawls that don't get fully back in time to catch the next gear tooth.

Sticky dogs that don't get fully into the teeth to hold the wheels between pulses.

Weak spring on the clapper pawl.

Chattering hold or transfer relays.

There is a remote chance that bias on the 2050 is sinking too low and the tube is staying in conduction between pulses....I've not had this, but in theory it could happen if the little filter cap on the low-dc rect is too low. Easy to check for by measuring the voltage at that filter while a box is pulsing. A few volts drop is OK. Years ago I did find that a shorted signal line can cause the bias to sink so low as to trip the mech and keep it pulled in. After that test I separated the trip bias from the stepper bias. It only involves tracing the two blue wires then making another R-C filter (470K-ohm and 25 mfd cap) and placing one of the blue bias wires on that junction and leaving the other as-is. This isolates the two bias lines. Getting rid of tubes in the control canter eliminates all this but that gets complicated.

One thing to try is position the stepper so that you can look at the screws on the front of the wheels head-on, then select V-0 and see if a stepper wheel appears to slip backwards as it steps. This is more easily observed by removing the contact wafers -but then they must be properly placed back again....A bit of a pain.

--All this assumes a properly functioning wallbox. we may have covered this already but, has that been checked?

These steppers are not -that- critical -if they were most of my machines would be a mess On some machines I've gone hundreds of thousands of plays w/out opening the stepper box....I know, shame on me.... But if things work, I've learned it is best not to "fix" them. Most steppers get a thorough contact cleaning every 3-5 years or sooner if I measure too much resistance between wiper and rivets.

Once you get this working the only thing you'll likely ever need to do is replace the tube..For home use that will be someday way in the future.

Rob

Rob, and all,
I found a small shot of Deoxit #5, takes care of "too much contact resistance", on WIPING style contacts, instantly----no need to dis-assemble--just shoot, and forget !! (well worth the {high} price)
Ron Rich

Hi,

I did a full clean and adjust of the stepper. Unfortunately, the juke is not working at all. The jukebox will not go into scan mode from the wallbox. I must have mis-adjusted something. If I put pressure on the Transfer relay contacts (during the cycle), it will start the jukebox scan.

The jukebox works and plays properly when I don't select via the wallbox.

Rob, working through your suggestions....

1. I installed a new 2050 tube.
2. My parts list does not list a 100ohm resistor. Am I missing something?
3. I installed a new 5mfd cap.
4. Pawls appear to work briskly.
5. Dogs also appear to work well.
6.Springs seem fine, no stretching or bends.
7. No chattering.
8. Checking bias on 2050...a bit difficult for me to understand. I'm not an electrical technician and somethings with electronics leave me wondering how things happen.
9.Stepper wheels go forward crisply.
10. I have another 3W1 wallbox. I swapped them over, however, no change so I assume the wallbox is OK.

I intend to leave it for a few days and try 'fresh eyes' on the problem. If I get it scanning again, I'll then try to find why it selects the wrong record.

Kind Regards

Gordon....