TCC1 Restoration

[odyciv410]

Howdy folks, I am working out the bugs in my LPC480. It is experiencing the infamous scan twice no play issue. I have determined that the voltage at TP2 (pin 2) and (Pin 1) ground is very low. From my research, I believe it should be near - 300V but I am only reading - 29V. I have also noticed the two voltage regulator tubes (OA2) are not glowing. The OA2's test good. I reviewed the TCC1 schematic, and I plan to locate a test point to verify T501 is providing the 325V as it should. I have ordered a cap kit and plan to replace all the old capacitors soon. I am determined to have this fine machine entertain me again.
Steve 

[jukeboxmarty]

Hi Steve,

I wouldn't continue to power up that unit until it's re-capped; You don't want to stress the power transformer if there's a short.

Also make sure the 6X4 rectifier tube is OK and not shorted.

Take your time re-capping, and make sure you observe the proper polarity on the electrolytics. On this power supply, positive goes to ground.

Have fun and welcome (again!)  to the forum.

-Marty

[odyciv410]

Marty, YES, I am having fun with my project and thanks for your polarity tip. My kit came with many capacitors and I am identifying the ones requiring proper polarity. The electrolytics are marked with -> and C520 (the tantalum one) has a longer lead. The others are ceramic so I expect they aren't polarized. 

I have reviewed the schematic diagram and I agree, C512, C514, and C515 + does go to ground.
It looks as if C520 however is normally polarized and is wired - to ground. 

Also, I ordered another 6X4 just incase I find it shorted.

If you have more advice on re-cap process, it would be greatly appreciated.

Thank you, Steve

[odyciv410]

Folks,

Here is a lesson learned to anyone else attempting to restore a TCC1. The two screws mounting the Z503 left and right side pulse amplifier are torqued down too tight and are easily broken (screw head twist off) when attempting to remove. I would suggest maybe some wd40 spray on the screws to break the screw seal before unscrewing.

Anyone else have this issue?

[jukeboxmarty]

C520 should be a .068mfd 600v paper (film) capacitor, not tantalum. Older film capacitors may be marked with a '+' sign, but that refers to outside foil not polarity.

Most modern film capacitors do not have an outside foil designation and their placement in circuit is interchangeable.

[odyciv410]

Folks,
For those that are interested, here is a picture of the cap that let the magic smoke out upon failure.
photos.app.goo.gl/VY7uC7iNK19tWwrNA
Thanks,
Steve

[jukeboxmarty]

Yes, the link worked.

[odyciv410]

I have made progress on my Seeburg LPC480 TCC1 repair. I am excited to report that I have completed replacing all of the capacitors in the TCC1. I also replaced the two resistors in each pulse amps. The 3.3k fuse resistor was found failed open and it too was replaced. The TCC appears to be operational as I see both OA2's glowing as they were not getting power before.

Here is a link to a picture of the TCC1 component refresh if anyone is interested. photos.app.goo.gl/f88K6azKqVwB7F3Q6

I made a selection, and to my surprise, the jukebox scanned, stopped, pulled and loaded a 45. This looked very promising as I have not yet seen this juke load a record before. Unfortunately, the record loads up to play position and motor stops. The service manual is pointing me to the Auto Speed Unit. Researching at the moment, hints are appreciated.

I did notice speaker sounds from the needle lowering onto the record. This could be good news as to the Stereo Amplifier.

The record is currently stuck in the mechanism and I moved the needle to end of record to attempt eject but eject failed.

Thank you for reading,
Steve

[jukeboxmarty]

The 4mfd can capacitor is the most likely culprit causing the auto speed unit to fail.

Also check the contacts on the relay in the auto speed unit... make sure they are making correctly and not pitted.

[odyciv410]

I plan to rebuild the Autospeed Unit. I ordered a Autospeed rebuild kit - 45TASU-1 and plan to replace its contents.

[odyciv410]

Folks,
I have discovered an interesting clue while investigating this latest issue. Turns out I am not the first to service this jukebox. I show evidence of prior modifications to wires coming from the motor and to the motor capacitor as shown pictured in the link below. If you look closely you will see 4 wires spliced in and taped with black electrical tape for shielding. Any idea what the prior owner might have been repairing/replacing on this unit?

Bad Wiring: photos.app.goo.gl/Cpws2yP69zX5bCWY9

Thanks for reading,
Steve

Follow up! Here is a picture of the 4 corrected wiring joints going to the motor and motor cap. 
Good Wiring: photos.app.goo.gl/zty1KdgZn9ZFLHBW9

Someday it will entertain me again!

[jukenorman]

The motor has been replaced. You could tidy up these joints!

Norman.

[odyciv410]

Motor replacement seems to me a good thing. I am thrilled to learn this. Maybe my juke will entertain me once again soon.
Thank you Norman

[odyciv410]

Hi again Jukebox folks, I have replaced 4 capacitors in my Auto Speed Unit 45TASU1. See picture here. photos.app.goo.gl/W4nP2CL2DcUHQaV5A

Unfortunately, replacing these showed no signs of improvement. The motor still does not turn. The troubleshooting guide says if Power Relay contacts A, C and E do not close properly, the record comes up to play position and motor stops. As of yet, I have not witnessed the Power Relay (K751) Energize. A 45 record is stuck in playing position, and as I understand it, a "Clamp Arm Switch" closes and results in energizing the Power Relay. So, I seem to be running down a "Clamp Arm" rabbit hole. If Y'all have any suggestions as to how I can test the Power Relay, Power Relay Contacts, Clamp Arm, Test Points or any other helpful tips it would be greatly appreciated.

Here are other observations I feel compelled to report because I think they are important clues.
1) The TCC1 "motor on" light stays continuously ON.
2) When I move the Pickup to the end of the record I hear what sounds like a relay energizing hum. Record reject does not occur.
3) Selector buttons fail to latch and credit lamp is not lit. This is new as of today. Up until today unlimited play credits was observed.

Again, Thanks for reading and with perseverance, it will entertain me once again.
Steve

[jukeboxmarty]

You can test the basic operation of the relay by watching it... it should open and close with the clamp arm switch.

The contacts look a little burned in your picture. I recommend cleaning/burnishing/filing as described here:

jukeboxaddicts.proboards.com/thread/5/contacts-care-cleaning-replacement

If the relay contacts are not the issue, another possibility is the motor capacitor on the mechanism.