Phonoland

Ok, here is my next issues regarding the Magazine Motor!
The first two issues is solved, or at least do I know what to do.
I have two more issues regarding the magazine motor and it's voltage supply.

Lets start with this issue:
Windings in the Magazine motor is between 3-20 ohms, shortage? What should the resistance be if measuring over the brushes?
When running the motor the 2A fuse blows in the power supply after a few seconds.
I will buy a new rotor from Stamann (jukebox-world.de) in Germany or have the old rotor it rewinded here in Sweden. The cost is the almost the same.
As the motor blows the fuses I rotate it by hand to check that everything else works........of course it does NOT!
I have followed the manuals trouble shooting chart and traced the leaders from the override switch to the transfer switch/reverse relay, but I can't find anything wrong.

I start with a selection and the latch pins releases....OK.
The wobble ring activates one of the four switches....OK.
(Service switch & loading switch is on )
As this happens I measure the voltage in the junction box motor socket = 0V.

Questions:
Where is the cam wheel starting position when a new cycle starts?
Should the roller on the transfer switch actuator arm rest on the small protrution on the cam wheel or not? (see photo below)
If the roller rests on the protrution there is 0V in the motor socket, if the roller is off the protrution there is 30V to the motor.
I assume that the roller should rest on the protrution as the the voltage i will be cut off when the roller enters the protrution, (when I manually turns the motor.)

Regards/
Gunnar

Six hours down on the floor is not so fun, my back ache:


Actuator arm Roller on the cam protrution (0V to the motor):


Reverse Relay in Junction Box:


Transfer & Play/Mute switch:

Windings in the Magazine motor is between 3-20 ohms, shortage?

Gunnar, 3 ohms at approx 28VDC would be around 250 watts -so, yes that is a shorted turn on the armature. Those motors are better than what RockOla used, but I have had several go bad.

Before doing anything with that motor try clearing the carbon buildup between the commutator poles. Use a plastic for, edge of a card or similar.

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Should the roller on the transfer switch actuator arm rest on the small protrusion on the cam wheel or not? (see photo below)
If the roller rests on the protrusion there is 0V in the motor socket, if the roller is off the protrusion there is 30V to the motor.

That is correct. In general with this sort of cam operated switch the over-center switching should occur on the ramp -before the plateau.

Rob-NYC

Will do the cleaning, might be some carbon deposits or copper chips from the turning that I missed when cleaning it!

Let me know if you need me to take a picture of the start position (I have a 2150 with the same mechanism)
Brooks

Thanks Brooks!

The motor is away for rewinding as there must be a shortage between one or two windings!
I hope to get it back the comming week.
As it have been impossible to run the motor more then a few revs before blowing the fuse I dont know if the mech works or not.
Have worked on the title strips and worn dome frame while waiting for the motor!

Yours looks to be in so much better shape than my 2150 was so I suspect all will be fine. I'm sure you know this; however, you can manually rotate the main cam counterclockwise (when viewed from above) to verify the 'cycle' works properly (raising the arms to load the records, set the spindle, needle brush, pull spindle in, lower arms, etc.). The hard part is that it takes quite a bit of strength to rotate it yet you want to do so carefully to see if anything is binding. So you are on the line between needing a lot of force to turn it and not wanting to force anything.
Brooks

Yes, I have rotate the cam by hand to check bindings, and it seems like I have all parts and adjustments in place, but there is always something........
One thing I observed was that the record seems to wobble a little (to much???) after the three small hooks have griped it!
But it's maby ok, could also be the record itself that is warped.

Gunnar, the two springs that lift the record are, in my opinion, excessively strong. I have always weakened them by careful stretching. This brings down the lift force to approx 12 oz. for the 200's and 6-8oz. for the 100-104. Once done that main gear turns easily during the lift retract.

As for the wobbly record, as long as the record isn't actually slipping and is clamped reasonably firmly it is nothing to worry about. Records played vertically will often look a bit wobbly simply because you aren't used to viewing them that way. It is a matter of perspective.

Rob-NYC

Got the rewinded rotor yesterday, it is a real beauty!
Now it's time to see if the mech works and if I have done my work as I should!

The rewinded magazine motor is mounted and after approx 40 years of silence the jukebox is on track again

http://s236.photobucket.com/user/gbak/m ... 5.mp4.html

The next step will be to find out how to reduce the hum/noice from the AC turntable motor and tonearm.

Gunnar, you have done a --remarkable-- job with excellent detail work.

Some suggestions:

- The T-T rumble can be reduced by replacing the rubber standoffs that are supposed to isolate the motor mount from the chassis. Make sure that no metal part of the motor chassis touches anything.

-The original pickup is a ceramic and the input is along with the tone circuit are "tuned" to produce a hump in response @ about 100Hz. this unfortunately is right around the vicinity of the motor vibration (yes, I did measure it on a 2400). A big improvement in overall sound can be attained by installing a magnetic pickup with a preamp and also a proper crossover and real tweeter (one is adequate since the cabinet is mono acoustically).

-Given that the cabinet is mono, some noise reduction can be has by strapping the input to mono at the input. This of course eliminates the stereo.

Again, first-rate work.

Rob-NYC

Thanx!

I have four new rubber standoffs mounted, but they seems not to be enough efficient. If I hold the motor by my hands when running the rumble is significant lower so it must be in that area I should focus.

I have looked at a pickup replacement earlier, the magnetic + RIAA seems attractive but not my first priority right now!
Which pickup will fit the tonarm (and also my expectations)?

Is there any shortcut to adjust the needle pressure on the record without the correct equipment?

/Gunnar

I have never been able to completely rid those machines of rumble. Assuming there aren't any clumps of hardened grease & dirt unbalancing the rotor, I really don't know what else to suggest. Back in the late 80s I was going to experiment with using a low-speed-low voltage DC motor to directly drive a pulley sized to work with the flywheel. The motors I had to try here were lost when the shops on Tenth ave (jukebox district) closed. I also found that a slight amount of rumble came from the main bearing though careful lubrication dealt with that reasonably well.

Regarding pickups for that arm, key is the ability to get a stylus that will track in the 3-4gm range and, due to limited clearances, a fairly low profile to assure that the stylus will clear a rising record.

This shot shows four examples:
http://s1192.photobucket.com/user/Rob-N ... rt=2&o=189
First is the original 8t for reference.
Next is a Pickering V-15 DAT series. This is what I used on all of those machines. It is identical to the V400.2 but both have been discontinued. Some NOS may be available and the later 500 series has a similar body.
Then there is an Ortofon LM20. This cart has a range of styli that (hopefully still) include a styli capable of higher tracking force.
Finally there is the Shure M44. This was used by Rowe from 1966 till the end of their vinyl machines in the mid-nineties. Wurlitzer OMT used them as well and there are a wide range of styli available.

In using a magnetic you will have to add a -slight- amount of weight to the rear pocket of the arm to bring the balance back into the adjustment range. The magnetic carts are heavier.

There is no real substitute for the spring gauge when setting VTF. However, if you set the stylus on a record, turn off the power and look closely you can set the force to the point where the cantilever shows little-no compression when against the record. That will get within the acceptable range for that stylus type. The other area is the trip switch. Here is my method of dealing with that issue:
http://s1192.photobucket.com/user/Rob-N ... ort=2&o=70

Rob

Rob,
Once again--you and I do not agree on a tone arm ! I would never attempt to force that switch feeler against the tone arm for the full record--I think that the WurliTzer engineers knew exactly what they were doing by having that "feeler" stopped at the last section of the record. Ron Rich

Ron, if you read my description on the pic-link it mentions that I rebalance the are to offset the loading of the switch. That arm was designed in the Cobra era where 10gm was the spec. It was primitive and IMO, the weak spot in an otherwise good mech.

As designed, the old style switch exerted significant backward pressure on the arm and stylus. the keeper that was used could not be setup to just load the spiral grooves as the switch was not as precise as the later ones. If I got the keeper adjusted to the point where it didn't load the playing grooves the trip switch would not be reset. If you looked at records used in that era of Wurlitzer you see the classic 'scalloping" wear pattern particularly on styrene disks as the arm neared the last playing grooves. When using a lighter tracking magnetic this also caused hopping.

On the later models beginning around the 2900 they used a much more precise switch and there it is possible to set the keeper to keep the loading off most-all of the playing grooves.

My friend late Tony D. who headed the service dept. at Al Simon Co used to joke that i was trying to get a Cadillac ride from a Mack truck.

Rob