seeburg AY 160 phantom selections

Norman, you are placing the horse behind the cart. Unless there is a solid, low impedance route to ground from the W-I source (D-link) nothing else will matter.

A scope will be of no use unless it has a triggered-storage function as this is a one-shot pulse. It is also unnecessary. This is a simple continuity problem.

So, review what we covered earlier in this process, Open the link again and start looking for when the continuity from the D-link is lost or becomes high impedance.

Rob

Checked K sliding contact in credit unit contact clean Insulated side clean. Voltages within 10 % of whats shon in service manual voltage on one side of diode is -145 volts the other side .03 volts. Quick question : With link D and E CLOSED what should the voltage reading be between D and ground? Thank You

If you understand the circuit in the simplified diagram, there should be -no- voltage at E-D to ground in normal quiescent state. There is only a brief pulse there at the time of Write-in.


It is possible for leakage to occur across the Write-In contacts in the credit unit and this, in some cases, will kill the pulse. However if you have a steady 145-150 volts on the 10 mfd cap at the diode, this will not be the problem.

At this point the focus is on the chain after the E-D link

Rob

Thank you Rob--going from d through the keyboard to ground where is the end point the schematic in the shop manual, doesn't show clear the ground point. Thanks Norman

Ground is any solid point on the chassis.

Use this simplified diagram:

http://www.fileconvoy.com/dfl.php?id=g9 ... 68ed4ff8b6

On your machine you will not have a 9 or 0 -but other than that the selector and associated wiring are the same.

Rob

Thanks Rob- put ohmmeter from test point D (link Open) to pin 33 ofTormat memory unit socket. got 185 ohms with a letter and a number button pressed. is this resistance too hi and if so what should I get? Thanks Norman

Norman, on the"newer" machines (160 sel) the thermistor (R32 on simplified) is moved into the Tormat itself, so at/near 190 ohms from "D" to chassis ground you are getting a correct reading.

Hold down the "1" key and go through all the letters. You should see reasonable consistency in the readings. Then hold "A" and go through the number buttons.

If all above show good continuity --to chassis ground-- it is likely that the keyboard contacts are OK.

Check the reading from pin Pin 8 of J16 (credit unit plug) to the E-link taking into account the lack of the thermistor (R32). Then measure from Pin 9 to Pin 8 while pulling in the cancel solenoid on the credit unit. There should be little or no resistance there.

Rob

Rob- Thanks I am going out of town for 2 weeks will check this when I return Thanks Norman

Rob-NYC. Im back and abck to work on the AY160.In your last post youtold me th check resistance betweenD and ground with letter and number buttons pressed
With the # 1 button and each letter button pressed I got between 185 and 187 ohms.. with the letter A button and each Number button pressed I god either 196 or 197 ohms. between pin 8 of J16 and E ( link open) I got 51 ohms. with credit unit removed from jukebox I got a reading of .2 ohms between pins 8 and 9 of credit unit plug. Still no results. Thanks for your patience and help Norman

Norman, with the credit unit just sitting (no cancel solenoid pulled-in) there should be NO continuity across pins 8&9. They only close at the moment of applying the W-I pulse.

If you are getting a reading there check the W-I contacts -they do eventually develop a carbon path across them due to the write-in voltage. Again, in the 'at rest" position it should be open circuit.

With the # 1 button and each letter button pressed I got between 185 and 187 ohms.. with the letter A button and each Number button pressed I got either 196 or 197 ohms. between pin 8 of J16 and E ( link open) I got 51 ohms.

That all seems correct. Bear in mind that the 190 ohm thermistor is in the Tormat on these later units -not in the TSR as depicted in the simplified diagram.

Rob/NYC

That is correct with the cancel solenoid NOT pulled in there is infinate resisantce between pins 8 and 9 of the credit unit plug. with the plunger pushed in there is .2 ohms resistance between pins 8 and 9. Thanks Norman

hello all still trying to get the AY to pick up selections. I am suspicious about the diode,cr 502 in the AY manual Was told to use a 1N 4004 diode the eletronics parts store (NOT Radio Shack) said this crosses over to a ECG 116 or NTE 116. Is this correct or did they sell me the wrong part. I am getting neg 162 volts on the plain side of the diode and neg. 005 volts on the cathode(Stripe) side. is this correct? when a selection is made, how much voltage should pass through the letter and number switches and then to to the individual torroid? In a act of desperation i tried shorting out the diode for a 1/5 second as i pressed A1. mech picked up A1 and all the other # 1 s on the left side of carriage. Thanks again for your help Norman

Norman, the voltages at the diode are a little high, normal is 145 -+ but I don't see this as being a problem.

The diode's function is to clamp the W-I pulse current at a certain level. Too much voltage/current and toroids that are not at the intersection of the chosen letter/number will start to flip. That is what happened when you shorted the diode, it also happens when the "low" 0A2 opens.

Normally though, when W-I current is excessive all of a number and latter will flip and play.

The NTE116 is fine, though I've never had to replace an original.

I don't know if I've asked, but have all capacitors in the W-i been replaced? Critical are the .068 which determines pulse length. The .01 w/47ohm in series and the 10mfd.

It's hard to get a true idea of the W-I voltage because it is so short and there is a coil (the 27mH) and latent resistance in the connections.

I have to say I'm as frustrated as you are here...well almost...I've never had a case where good components, good connections and proper voltages didn't result in normal operation. If I had the machine in front of me it probably would have been whomped in about ten minutes....that's typically how long it takes in these cases on location.

This will require more thought.

Rob

All caps in the TSU have been replaced however on the chance that I got a defective one, I will replace the .068 and the .01 with Orange drop caps and see if this helps thanks Norman

Rob: the 10 mfd cap you pointed out was replaced with a 33 mfd unit would the higher mfd value effect the pulse length? Thanks Norman