Seeburg AY 160 blows fuse

[robnyc]

Norman, 9 volts is too low. that is just inside the critical grid region for those tubes. It seems as though the bias is being drained by something.

You have a TSU-7 and those have drop-in steppers. if the stepper is there, remove the two white plugs at the bottom of the stepper. This removes the stepper as a possible drain.

When you replaced the caps did you make sure that the 25VDc cap is connected with positive terminal to chassis ground? Normally if an electrolytic cap is connected in reverse polarity it would "pop" -but sine there is a 470K-ohm ahead of it, it might just leak heavily.

If the voltage is approx 41 out from the rect but low on the other side of the 470 K resistor, this is where to investigate. It is necessary to get correct bias befor proceeding. I suggest keeping the two mech plugs out as well was the stepper or pass through plate (if no stepper). The plate will not normally have any connections for the bias...but with tampered equipment, ya never know.

Rob

[Ron Rich]

Hi Norman,
OK--Is this with the 2050 installed, or without it in the TSU ?

[vaguy22]

Rob: Again thanks for the help. With the 2 stepper plugs and the 2 mech plugs still getting only 9.5 volts on pin 5 of the 2050.here is the voltage breakdown from rectifier to 2050 grid. Voltage at rectifier out is 42 volts, after the 1800 ohm resistor (R533) voltage is 28 volts, after the 470K resistor(R521) voltage is 21 volts. after the 1 meg resistor(R508) voltage is 11 volts and after the other 470 K resistor(R510) voltage is 9.5 volts. Resistor numbers taken from page 13036 of Seeburg DS manual for TSU 7 selector. 25 mfd lytic is installed corerctly positive to ground lug

[vaguy22]

Ron 2050 is installed for all the voltage readings in the above post. Thanks again for your help.

[Ron Rich]

Hi Norman,
Not what I was attempting to axk--I need to know, what happens when you scan, lift the detent lever, with-OUT, the 2050 installed. I am thinking you have a mechanical, as well as electrical problems ?? Ron Rich

[vaguy22]

Sorry Ron, for the misinformation. with the 2050 OUT of it's socket mech will play record ok. not a mechinal problem. also i geT buzzing if i try to hold back the detent lever when it trips with 2050 IN the socket. Thanks Norman

[Ron Rich]

OK--try the following--remove the 2050--with power OFF, measure resistance on both terminals, of the end of record reject switch, to ground. Then with tube still removed, scan mech, and lift detent--allow it to begin play, turn power off and measure both sides of the reject switch to ground, now--Let me know what you see ? Ron Rich

[vaguy22]

Ok Ron. with 2050 OUT of socket top terminal of record reject is infinate res. bottom termanal is 5.0 ohm. obvisually got a short there will work on that tomorrow.with mech in PLAY position,power off top terminal of record reject switch is 1.0 ohms bottom terminal is also 1.0 ohms will try to find short in the next day or so and repore back again thanks. is there any perticuliar place these wires would short? Norman

[Ron Rich]

Norm,
Something's "messed up !! ONE of the two terminals should be connected DIRECTLY to ground with a short wire screwed on the terminal support, below the tone arm -- This should ALWAYS read "shorted to ground" ? --see mech schematic -- Ron Rich

[vaguy22]

Update:I unsoldered the 2 wires to the end of record switch to check if switch was grounded. switch was ok. soldered the lower wire which goes to the ground lug under the tonearmback on the switch.Ttraced short on the other wire that was removed from record trip switch. With mech in PLAY position and 2050 in socket, both mech plugs out, traced short to the "P contact at top of cam switch contacts. when i lift the "P contact ground goes away.Again, thanks for your help.Norman

[Ron Rich]

Hi Norman,
Just had a thunked-- By any chance, is there a 33(T)ASU installed, and connected in this phono ?? If so, eliminate it--plug the mech plug directly into the TSU--and see what happens !! Also--are all record slots filled ? Ron Rich

[vaguy22]

Hi ron. There is NO 33Tasu autospeed unit in the juke. never had one since i got the juke. I have only had the juke a month. NO records in juke. Still trying to find out why the bias voltage on the 2050 is so low. thank you for the help Norman

[Ron Rich]

Hi Norman,
OK--then it's NOT an "AY 160--it's a "Y-160"--the "A" in this model indicated n Autospeed was factory installed. Which "pricing unit" is installed in this phono ? In any case, un-plug it, and see if that changes the bias voltage. Ron Rich

[vaguy22]

hi Ron, At one time it was an AY 160 (it has the 33 1/3 logo on top glass) then someone removed the auto-speed unit turning it into an instant Y 160. NO difference in bias voltage weather pricing unit which is an UNIVERSAL pricing unit--USPU1 Is plugged in or not plugged in Thanks Norman

[Ron Rich]

Hi Norman,
OK--It was an AY160 U model at the time it left the factory--does it have a RCSU or a TJU, and which number, installed in it ? Ron Rich