Officepot
Member
I am a brand new jukebox owner and have experience with electronics, but never a jukebox! Most definitely never worked on something this old! I have an odd combinations of components and would like to reach out and ask for some help. I identified my amplifier as a Wurlitzer 538 Amplifier. The label was mostly rubbed off but I do know the 538 is very close to the 534... I am pretty sure this is a 538 as the can caps match the values they should be in the 538, and the can caps in the 534 are different values.


So I purchased the cap kit for the 538 and completed the capacitor rebuild. This was my first time ever replacing can caps so here is how it looked when I was done, notes on how to do it better always appreciated.

Hurray! I then turned my attention to the power supply. This is when stuff gets weird... it seems my power supply is not for a 538, at least, it definitely is not the same power supply that is in the full 538 amplifier schematic. So I begun searching and this is 100% the power supply in the 534 schematic! It has the same single tube on the chassis and it has the full bridge selenium rectifier. Well I though okay, I do have a full bridge replacement for this rectifier so I will replace that. So I did. What I do not have, is the correct capacitors to replace the can caps in this power supply, since Victory Glass sent me capacitors for the 538 power supply. So I ordered the few caps I need and am waiting for those to arrive to complete the recap of this entire unit. But I figured I would give the unit a chance to turn on and see how it does. At first, after some squinting and flinching for a first time power up, I turned it on and everything seemed okay. But my 30V line out of my full bridge was missing, so the motor did not spin and it seemed there was an issue. Then, randomly, about 5 minutes later, my 30 volts appeared, my 5U4 lit up and the jukebox came to life! I was able to put money in and see the wheel attempt to select a record! Then again, just about as fast as it came, it left again. No more 30v line, no more glowing 5U4. Dead other than the nice glow of the florescent bulbs.


Okay, so I started looking into the power supply to see what has been done, first, I noticed 3A fuses had been installed in the 2A fuse holders. When I got the jukebox, these were both blown. I made a rookie mistake and assumed the previous owner had put the correct amp fuses in and just replaced them with 3A fuses. After I noticed my mistake I have put 2A fuses in. I am REALLY hoping I did not cause damage to the transformers by doing this but I guess if the previous owner blew 3a fuses... the damage was probably already done. Anyways now I am sure my full bridge was wired wrong, as the schematic shows -30V going to the output of the junction box and mine was outputting +30V. I think I did have it backwards and send +30v to the junction box. Yikes on my part. Anyways waiting for my capacitors to replace the can cap in this power supply, as well as a new 5U4 tube for good measure. I am unsure what I fried when I put the wrong polarity in the 30v line but it seems to be completely dead now. Also what would cause my 5U4 tube to not work until it randomly lit up with the 30v line? I figured the bad cap could cause this but after looking at the circuit I am unsure the capacitor would effect the 30v line. Thanks everyone.



So I purchased the cap kit for the 538 and completed the capacitor rebuild. This was my first time ever replacing can caps so here is how it looked when I was done, notes on how to do it better always appreciated.

Hurray! I then turned my attention to the power supply. This is when stuff gets weird... it seems my power supply is not for a 538, at least, it definitely is not the same power supply that is in the full 538 amplifier schematic. So I begun searching and this is 100% the power supply in the 534 schematic! It has the same single tube on the chassis and it has the full bridge selenium rectifier. Well I though okay, I do have a full bridge replacement for this rectifier so I will replace that. So I did. What I do not have, is the correct capacitors to replace the can caps in this power supply, since Victory Glass sent me capacitors for the 538 power supply. So I ordered the few caps I need and am waiting for those to arrive to complete the recap of this entire unit. But I figured I would give the unit a chance to turn on and see how it does. At first, after some squinting and flinching for a first time power up, I turned it on and everything seemed okay. But my 30V line out of my full bridge was missing, so the motor did not spin and it seemed there was an issue. Then, randomly, about 5 minutes later, my 30 volts appeared, my 5U4 lit up and the jukebox came to life! I was able to put money in and see the wheel attempt to select a record! Then again, just about as fast as it came, it left again. No more 30v line, no more glowing 5U4. Dead other than the nice glow of the florescent bulbs.


Okay, so I started looking into the power supply to see what has been done, first, I noticed 3A fuses had been installed in the 2A fuse holders. When I got the jukebox, these were both blown. I made a rookie mistake and assumed the previous owner had put the correct amp fuses in and just replaced them with 3A fuses. After I noticed my mistake I have put 2A fuses in. I am REALLY hoping I did not cause damage to the transformers by doing this but I guess if the previous owner blew 3a fuses... the damage was probably already done. Anyways now I am sure my full bridge was wired wrong, as the schematic shows -30V going to the output of the junction box and mine was outputting +30V. I think I did have it backwards and send +30v to the junction box. Yikes on my part. Anyways waiting for my capacitors to replace the can cap in this power supply, as well as a new 5U4 tube for good measure. I am unsure what I fried when I put the wrong polarity in the 30v line but it seems to be completely dead now. Also what would cause my 5U4 tube to not work until it randomly lit up with the 30v line? I figured the bad cap could cause this but after looking at the circuit I am unsure the capacitor would effect the 30v line. Thanks everyone.


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