I finished testing three black boxes on the STD4. I cased them and re-tested. All checked good so I put the tamper proof stickers on them and added to stock. These sell fairly quickly and sometimes it’s all I can do to keep up. The black boxes are the best spares one can buy for their microlog jukebox. Microlog is a term for any juke that uses the black box.

I repaired an old six digit Bally pinball display for Jeff’s Eightball pinball. I hadn’t worked on one of these for 20 years. All digits were missing one segment of display. That’s a pretty good indicator of a bad chip and indeed; when I looked at the chip the top of it was bulged and cracked. I replaced the CMOS BCD to 7 segment driver chip and I’m sure it will check fine. There are two other “must check” areas on these displays. First is the solder cracks you are certain to find around the pins on J1. The other are the six 100k 1/2w resistors used for each digit. I was surprised by how quickly this information came back to me but I had worked pretty intensely on pins back in the day.

The PA-4 Library Unit pre-amp got finished. I was done recapping it and decided to check the can voltages to see if I could get by with the stock one. One section was about 230v-almost a hundred volts low, the other two section voltages were ridiculously low reading about 70v instead of about 250v. I had a bad can capacitor. I used three 22uf 450v axial caps to replace the can while leaving it in place for looks. This has become standard operating procedure on every tube amp. The cans are scarce and when you can find them too expensive. I used to not replace the three and four section cans but they all leak too badly anymore. I tested the unit on the semi-permanent outboarded Library Unit on top of my what else? Seeburg speaker. It lives under a towel when not in use. I run the pre-amp through the stereo system to the speakers. Being a pre-amp it cannot drive a speaker by itself.

Back to work on the SMC1 mechanism. Today was solder n’ switch day. I installed the trip coil after cleaning its bore and the plunger. It needed an adjustment upwards. When tripped the plunger should have a bit of “head room” and this one had zero clearance. The trick on this is to adjust the top bracket first, getting your clearance and then loosening the bottom bracket and holding it upward against the coil while tightening the two screws. Keeping the top bracket parallel is paramount. Get it tilted and the plunger may bind. Warmed up my Weller and soldered the leads for the trip coil back in and then the motor leads. After that I went through the switches cleaning and adjusting. Any burned spots need to be filed down until its gone. I have several files and adjusters to make life a little easier. Once I file a contact down I burnish it or basically polish the contact with finer files. If I had to equate it to a sandpaper grit maybe 600 grit for final finish.

I applied a new rack number strip and mounted the magazine rack with hex head screws and not those damned Philips head screws the SMC’s come with. I like to put the mech in Play position about half way down its travel and then align the rack to the mechanism. I hand-rolled the mech to 100/200 and 179/279 and set the limit switches. Then that’s it! Done. I took the mechanism out of the SMC2 and put the SMC1 in. I’m very pleased that all it needed was a tiny trip switch adjustment and Clamp Arm 1 re-adjusted. Oh, the pickup cradle will not swing to the right for B sides. I’ll pull it apart tomorrow and hope nothing is broken.

Ever wonder where the hold-down bolt holes are? Here ya go.