Seeburg LPC 1 problem

Oh no .. not another one of these . I am getting lazy so will ask a question . This machine is as nice as it gets . Super clean and all original . The problem is it never plays the selection made . I can push A1 and it will at random just play something or nothing . Every selection i make just plays some random record and not in any pattern .

What i have done . Remove and polish the tormat contacts and make sure the little wires under the sliding contact block are all restored . Remove the keyboard and remove all 3 of the button contact sets and polish all of the switch sliders and check for any bent or loose contact blades .
Nothing changed , still selects wrong .

What next ?

Some suggestions:

Replace both 12AX7 pulse amp tubes with -known good ones-.

Check for sparking at the center terminals of the plunger block.

Make sure the machine is drawing readout current. initially, look for slight flickering/dimming of the two 0A2 tubes as mech scans left-to-right. When scanning right-left the 0A2 should be solidly slightly dim -no flickering.

Check the value of the 4.7K-ohm resistor on the mech. This ground out the readout as mech scans right-left. this is often open and if so it will erase selections as mech scans, but the mech will not trip.

What does the tormat battery test reveal?

If you don't have an LPC manual, these should help:

http://s1192.photobucket.com/user/Rob-N ... ort=2&o=19
http://s1192.photobucket.com/user/Rob-N ... ort=2&o=18
http://s1192.photobucket.com/user/Rob-N ... ort=2&o=10
http://s1192.photobucket.com/user/Rob-N ... sort=2&o=9

There is probably more than one issue here. It is critical that the selection receiver and pulse amps be recapped and resistors checked.

Rob/NYC

Ken,
Iffin it twere me looking at this--the first thing I would do is slide the TCC out far enough to see the relays.I would then select something in the center of the rack--say A% and watch the relay as it scanned --Also I would select a center "B" side and watch that relay--if both relays energize, the "W" contacts are dirty. If neither energizes, try the battery trick, on both PA's, and see what happens--Ron Rich

Ok .... i may need to pack a lunch for this adventure I will get to it when i can . Thanks for your tips

Ok .. i replaced 12ax7 , OA2 , 6X4 and recapped the chassis . Those 2 relays have been cleaned and work as in they will close when a record is pulled in to play .
There is no spark on the center pins . There are sparks on the outer row . No spark on the inner row .
The OA2's both flicker . They flicker more when the meck is moving right , less going left .
The battery test causes the thing to play . I dont know the right way to start this test . I tap the battery in place and make a selection as normal . The mech will move and stop in the middle of the rack and start playing records in a row . I didnt see how many past about 6 or 7 .

How do i start the test after the battery ? I do the battery then plug the wire back in the hole and select A1 .

No change , still total random selections .

It seems you've done the battery test correctly, that is negative end of battery on chassis and tip of pulse amp plugs to positive side.

With the RCA plugs back in the pulse amps the mech should trip immediately when scan starts and service switch in in 'operate" -normal.

There should be no sparking at either plunger, although a few tiny ones at the front or rear is OK. Frequent sparking indicated either a mis-adjusted detent switch or mus-alighned tormat.

The 0A2 should not flicker with mech going towards the left. There is a 4.7 k-ohm resistor in the mech that is switched-in at that point to kill readout voltage.

One thing to try is to unplug the keyboard and start the mech scanning. It should just scan out and stop.

Rob

Ken,
Do you have the service manual "package" for the LPC? If so, see the "Information, and Operation" (I & O) section. Read the portion concerning the service switch. Once you have energized BOTH of the RCA plugs with a good, "D" cell, use the service switch to start the scan. If the read-out / sense / detent circuits are good, it will begin with A-1, and play both sides of all the rest of the records.
If it fails this test ( and from what I see so far, I expect it will). The plunger on the frog, and/or the detent switch itself will need to be serviced. Plungers MUST have silver left on top--must be "filed smooth", then burnished. Detent switch , the same--see Service Manual for all needed adjustments.
( If you have a copy of my "Seeburg Mechanism Guide", it may also prove helpful here)
If it "passes" this test, it has Write-in problems, that will need to be "trouble shot"--
Ron Rich

Ok guys i will try that stuff . The contacts spark just a slight bit .

I have restored several of these tormat machines including 3 LPC and 3 discotheque and a couple of them were real dirty rats nests and none of them had this problem even totaly unrestored .
Strange how this almost perfect LPC has these problems .

Just to elaborate a bit on my suggestion to remove the keyboard from the circuit, the idea is to isolate this as either a write-in or readout/noise/mechanical problem.

After trying the battery test erase any remaining flipped toroids by reversing the batter (pos to chassis -neg to RCA pin). Put back into the pulse amps and start mech scanning with switch in 'normal" (play) position.

Watch the trip relays. If relay pulls-in and mech trips you have a noise problem.

If ti trips w/out relay (rare) the problem is mechanical (clutch). On my first HLPC the clutch was so worn and dry when I got it that it would occasionally buck to the point that it would actually transfer a record and play. I took the clutch apart and filed down the clutch member's rounded notches and thoroughly re-lubed it.

Rob