Seeburg DS 100 pulse amp problem

Hi Rob, again thanks checked g and H link with link closed--0 volts with both mech plugs out and service switch plug out. can not find 36 ohm resistor perhaps someone ahead of me replacet it with a diffrent value. will check resistors in vicinity and get back to you tomorrow

I don't use the links, and it's too late fr me to dig out a schematic, but you MAY also need to un-plug the pricing unit to get a voltage reading there ? Ron Rich

Ok, if there is no reading of 300vdc from the junction of H & G to ground you have localized the problem.

-Are the 0A2 tubes glowing purple (if original design).

If the 0A2 tubes are not lit: Check for voltage at either side if the two resistors coming off the two filters. If no hi-volt reading there check for it @ pins 1 & 6 on the 6X4 or just change the tube with a known good one.

Bottom line here is without the minus 300vdc supplied to the mechanism it can't read out -thus it can't trip.

For the above tests it is a good idea to keep the mech and service sw unplugged.

Rob

Hello Rob, checked for voltage found bad resistor replaced nou have 290 volts at the G and H link. Now what? Thanks for the help Norman

Norman,
Now see what happens if you use a good D cell ??
Ron Rich

tried new D cell no results.. thank you Norman

Did you make a test jig as I described earlier--? Did you retry the jig ?
Have you metered the RCA plug as I described earlier ?? What is the reading ??
Ron Rich

Norman, in addition to Ron's suggestions, let's go back and slip the paper between the plungers and tormat , close the detent switch and look for that 290+ volts (plug only the two mech plugs in). If that readout voltage is there we are down to:

-Broken plunger wire.

-Misaligned Tormat.

Broken wire in the Tormat pickup look (RCA plug).

It is possible that the detent switch is worn to the point that it isn't closing enough but usually when this happens the mech will still trip at least on some slots while scanning.

I've had two occasions where too much oil (Mea culpa) soaked the detent switch and resulted in a conductive path that drained off the R-O voltage. To test for this: Attach your meter to the G-H link and ground. With the paper between Tormat and plungers, turn the motor by hand to move the mech a few slots. As the detent sw closes the meter voltage should the same -not drop. this indicates that the mech ckt is not draining the voltage due to leakage. A simple neon tester is good for these tests as well.

Bottom line here is that we must get it to pass the battery test in order to proceed with further selection system troubleshooting -if any is still necessary.

Rob

Rob, Norman,

Add two more things to the above--maybe--
If the record rack has been removed, it is possible for everything to be totally miss-aligned.
The "contact block pins" could be worn to the point that there is no silver left to make contact with the (hopefully still) gold flashed rivets on the bottom of the TMU.
Rob, Never experienced a leaky Detent switch, but have seen this happen a few times on the upper switch stack--twice, it was a very dangerous problem, as the motor power (117vac) was leaking thru the support screws to the mech chassis--OUCH !!! Both times one of Rob's Geppetto friends had replaced the main fuse with a jumper wire-wonder why ?? Ron Rich

Hi Ron. the resistance reading on the tormat RCA plug is 1.5 ohms. is this correct? tried putting papre insulators on tormat pins voltage at point voltage remains the same whendetent switch is either open or closed. Again thanks for the help Norman

That's low--usually read about 3 ohms--but this is VERY meter dependent. Did you double check the solder job and the wire itself, all the way to the TMU for cuts in the insulation ?
What worries me is voltage ( what did it read?) on the pins with the detent switch open--should NOT be there -- would indicate a closed (shorted) switch-- Ron Rich
Ron Rich

Hi Ron. Meter used was a craftsman digital meter using the 200 ohm scale.Carfully dissambled tormat and checkd contnituy of signal wire all 3 conductors read good. willl check voltage on pins tonite. Thank you Norman

I have a Seeburg DS160 that I have spent many hours troubleshooting and perhaps some of my journey will help you. I just got it working today!

The customer complained of the famous "scans twice" problem and I was determined to fix it.

I spent time following the service manual steps and I could not trigger a selection even by applying the 1.5V to the pulse amplifier. This was the first problem.

He had the amplifier previously re-capped but the selection unit and pulse amplifier were un-touched, so I replaced all of those. I also found a bad resistor in the pulse amplifier.

Now at least I could trigger a selection by pulsing the pulse amplifier with 1.5V but still could not do the read-out (applying 1.5V battery to the RCA jack to the Tormat unit).

This is where I had problems still. I found that if I used a bench power supply set to constant-current of 1.5A (the
ideal current to set and read the Tormat) I could actually manually set and read out the Tormat by applying the current between ground and to the rivets of the Tormat, and reversing to read out. So the pulse amp was working, just not the read out still.

I was sure everything was good but now I figured I was not getting enough current to read out. (By this time I had cleaned, adjusted, fiddled with EVERYTHING). I ended up doubling the 0.15uF capacitor which stores the read-out pulse to 0.30uF and sure enough, works like a charm. Still 290V as always, but a stronger pulse.

Best I can figure, the new capacitors I was using just could not supply the current that the old paper capacitor could even though the value was correct.

Hope it helps someone.

By the way, using a 1.5V cell to set the Tormat to all selected (or all de-selected depending on the polarity) still never worked for me. Maybe the batteries I had were just not the same as back in the day. A 1.5A constant current power supply did work.

Sure is an amazing jukebox for the time.

Cheers,
Rubin

Rubin, I don't know where you got the figure of 1.5 A for R-O -but it is bizarrely wrong.

Typical readout current at the plungers is 34ma @ 300VDC.

The HVDC supply is not even capable of 1.5A.

the time constant of 0.15 has always been adequate in the dozens of machines I've rebuilt and the 9 old relics I have on location. I use mylar caps here, but type is not critical, minimal leakage is.. I suspect other components are actually at-fault here. One important one if the 100mH choke at the detent sw. Typical failure points are the resistors inline with the R-O source.

By the way, using a 1.5V cell to set the Tormat to all selected (or all de-selected depending on the polarity) still never worked for me. Maybe the batteries I had were just not the same as back in the day. A 1.5A constant current power supply did work.

Right there indicates a problem that has not been addressed. I carry an old AA cell in my briefcase tools and that has always been adequate to flip all the toroids.

There is more work to do on that machine.

Rob-NYC

Gents,
My once great, but not too long memory has failed me --I can't remember why, but in SOME instances, no smaller size, other then a (good, of course) D cell, will flip the Tormat ! Also, if applying 1.5 volts directly to the tip of the RCA socket, on the PA, one should use a #112 lamp in series, for an accurate test. Ron Rich