Seeburg Q100

I have a Seeburg Q100 jukebox and the carriage scans twice and stops without playing selected records. I have the trouble shooting guide and performed test 'B', the mechanism did not trip so I tried test 'M' . The mechanism tripped when I connected the jumper from 'A' to 'B' on the test terminals. I replaced the 12AX7 tube and it still scans twice and stops without playing selected records. I also checked the memory output unit output plug and that appears to be okay.

Any idea what I could heck next or how I could correct this problem? Thanks for your help on this.
Greg

H Rascal,
Check/replace the cap and resisters inside the pulse amp--Ron Rich

Rich,
I took the pulse amplifier off but i am not that savvy replacing transistors or determining which ones are bad. Do you think I could find a pulse amplifier replacement, part J510? Any suggestions where I may find one on line? I guess you ran across this problem before so it most likely is the pulse amplifier. Thanks for your help and let me know if you have any other suggestions and where I may find this replacement.
Thanks again,
Rascal

That part number is incorrect for the pulse amplifier, my bad.

Rascal

I don't know if you can find a "good" one anywhere, but I can rebuild the one you have--
PM me if you wish to ship it to me--Ron Rich

"Rascal" if you have narrowed the prob to the pulse amp, you may as well fix it yourself.

Replace the 0.047 cap that couples pins 1 & 7 on the 12AX7 socket. You can't miss it -it is right there. That alone will fix approx 85% of troubles in this area. There is also a 5.6 megohm resistor on pin 7 (12AX7) that sometimes drifts upward.

Not meaning to take business away from Ron , but really, these two repairs cost almost nothing and take about 5 minutes. Between them they take cure 99% of pulse amp problems.

While you are at it, I suggest adding a short wire from the shell of the RCA plug. Place a spade lug on it and screw it under any convenient chassis ground, screws on the pulse amp are fine. The impedance of this circuit is so low that any resistance in the ground shield can cause erratic tripping of the mech when a selection is made or other noise is introduced into the system.

Rob/NYC

Rob,

I guess you have come across this problem before and replacing the capacitor and resistor fixed the problem as I previously described. Thanks for the advice,I am hoping that radio shack would have the capacitor and resistor.

I don't quite follow where to attach the wire to the" tube shell", can you give me a better idea of what you mean?
Rascal

Rascal,
Unfortunately, "Radio Shack" will not have that cap, and probably the resistor, for sale. You will need to find a good electronics supply house for them. Also, while replacing those two parts will repair about 75% of them, the other items inside the PA also fail, from time to time--and the possibility exists that the problem is located somewhere else in the TSU. Ron Rich

Rascal. the resistor -may- be available at your local Rat Shack in the form of 10 megohm types. Use two in neatly soldered in parallel (either two 1/4th or 1/2 watt) this will give approx 5 megohm. this is fine for this sort of application.

For the cap try your local electronics service shop -if any still exist in your area. This is a super-common value and most any repair shop with have them.

As for the "Shell" i was referring to adding a short pigtail lead to the outer shell of the RCA plug that comes from the Tormat into the pulse amp. The idea is to guarantee a good grounding of the shield to prevent "noise" from tripping the mech. One end soldered to the shell of the plug, the other screwed to one of the screws on the pulse amp.

It is not essential, but i operate these old relics and given the age of the plug - socket surfaces and my desire to eliminate potential problem areas, it was worth it to add one to the pulse wire and another to each of the ground connections on the large Jones plugs (Tormat and keyboard).

Rob

Well I replaced the capacitor and resistor as recommended but it still scans twice and then stops. I tried "test B" again but this time the mechanism tripped when I put the jumper on "C" and put the other end into input of he pulse amplifier, so I did test "C" and the mechanism scanned so went to test "D". In test "D" the lamp glowed brightly when connected between test "H & A" so went to test "E". Connected test lamp between "G & H" and made a selection, the test lamp did not light at all. Cheek the fuse and that's okay but having a hard time tying to check if the plungers are sticky and the wires look ok to the RO circuit based on the sketch in the trouble shooting book. There is a yellow and black wire leading from the RO (?) area but then I found two blue wires that lead to the carriage that aren't connected to anything but were always like that when it worked previously.

Help! I have spent a lot of time trying to get this to work and it is getting very frustrating. Any ideas out there? Thanks for your help.
Rascal

Rascal, I have no idea what these various "tests" are -I don't operate from guides, only schematics. So if I suggest something you have already done -sorry.

When the service switch in "normal" position when the mech scans you should see slight flickering as the mech scans in the two 0A2 tubes (if that glow purple, newer ones don't glow).

There should not be any unused wires on any part of the mech.

On the plunger block (under Tormat) there are four tiny wires that go from terminals on the block to the bottoms of the plungers themselves. Looking from the rear, the plunger closest to you is for the "A" sides. The two in the middle are the ground return for the Tormat readout pulses. The plunger closest to the front of the mech is for the "B" sides.

If wires break on either the A or B plunger one, or the other won't work. If the center wires break neither A nor B will work.

So examine these plungers and their associated wires. Also make sure there is some overtravel of the plungers. Do a continuity test from the center plate contact under the Tormat to the chassis of both mech and selection receiver.

As a test: slip a wire under a screw that holds the Tormat center plate and slip the other end under one of the screws that hold the tormat in place. This will bypass the center plungers and make sure the readout pulse gets returned to ground. This is -only- meant as a test.

There are other things to try, but check these out first.

Rob/NYC

Rob,
Thanks for the information and suggestions. When the service switch is in the normal position when the mech scans, the two OA2 tubes (glow purple) do NOT flicker at all. This was similar to the test I did test "E" when I connected the test lamp between "G&H" and made a selection, the lamp should have flashed at each record space and the lamp was not lighted at all.
I checked the plunger block and all four wires are connected and intact. I didn't do a continuity test and I didn't t understand the other test you described by slipping a wire under the screw the holds the tormat center plate and slip the other end under one of the screws that hold the tormat in place.
You mentioned that there are other things to try so could you give me your suggestions of what to try next.
Thanks for your help.
Rascal

Rascal1,
I would do the following to trouble shoot this problem---
1. Check all TSU voltages.
2. Check the 5 amp fuse on the front of the mechanism--also check that the grounding screw is tight--caution-Do not replace this fuse, if blown, till you determine why it blew, as the TMU can be instantly destroyed.
3. Check the contacts on the "frog" that rides the TMU--they MUST be flat--not "gouged out", and they MUST have silver left on the tops of them.
4. Check the detent switch for "dirt", "pitting" and that the adjustment is correct, per service manual
5. if still a problem--check/replace any/all components in the TPA-1
Ron Rich .

Ron has saved me some typing here, to his input I'll add:

The G&H link appears to be a link that couples the readout power supply to the mech where it first goes through the detent switch (and the little choke coil on it) then on to a section on the reversing switch then to the plunger block where it pulses each Tormat coil as it passes.

With the G&H link opened take your indicator light (be sure it actually works) touch one lead to the "H" terminal and the other to the chassis (ground). The light should glow and be reasonably bright. If you have a meter read the voltage here H-to-ground, it should be around 300 volts DC.

There is a 33 ohm resistor in this circuit that fails eventually in most of the Tormat machines. Resistor color code is red-red-black. This is a common problem. Follow back from this test terminal and check all resistors (make sure power is off and no voltage remains).

While you have the G-H link open, unplug the machine place one lead from the ohm meter on terminal G -the other to chassis ground. Then manually turn the motor on the mech to get the mech moving slowly. You should see the meter go from open circuit to near zero ohms as the detent sw closes at each Tormat rivet.

Do you have a simplified schematic of the readout circuit?

Rob

Rob,
LOVE to make you "work"--two minds, even empty ones, like mine, are always better then one--
Ron Rich