New to the forum here. Hoping to find some help. Recently bought 2 Rowe WB100 Berkeley Model CD Jukboxes. One was working and one was "parts". Got both up and going 100% except for the neon tubes are giving me trouble. Went through the schematics and there isn't much there on the circuit. Checked for cracked joints, blown fuses, and the bridges for the start all good. These units power supplies do not have the pot for brightness adjustment.
Unit 1 had a bad LM317. 13 volts-ish in and 5 volts out. Checked value on resistors and seemed good. Changed out the LM317 and the diode for good measure. Now neon lights and is on for 1 minute before dimming to a point of flicker. LM317 gets hot. Have no basis on temp before...
Unit 2 had a hack with a 5 watt resistor in place of the diode that bypassed the LM317 circuit. This had a blown fuse and when replaced it "worked", but I am assuming it had the blown fuse because of over loading the circuit. I let it go for 30 minutes like this and the neon stayed lit. So I reinstalled the diode to see what happened and the neon lit but quickly cut out. Replaced the LM317 and now it is acting like the first. Lit initially and then dims out slowly over a minute or 2 with a hot LM317.
So this forum was the only place I found in google that had discussion on these units. Any ideas, common fails, things to test??? Hate to reinstall the hack, but want to wrap this issue up and move on.
I attached the schematic I was referring to above.
Thanks, Jon