As part of the cabinet and lid disassembly, I removed all of the cabling and cleaned it up. Seeburg used a gray-colored PVC zipper tubing to protect the larger cable assemblies. The smaller cables (two-five wires) were protected with tubing not having a zipper. The zipper tubing actually comes as a flat piece on a roll. One side has a molded-in tongue, and the other side has a molded-in groove. At the factory, a special harness was made which would hold the cable in place while you put the jacket around it, followed by pulling the ‘zipper’ (a specially-made plastic piece) that joined the two sides of the jacket together, completing the tubing. I’m not sure if it’s due to the stuff they made the tubing out of, or if it attracts cigarette smoke, or what, but every piece of tubing in that machine had a brown slimy sludge over it. For the zipper tubing, I contacted the original supplier who sent me one of the plastic tools to zip it back together (it simply pulls apart, but getting it back together can be difficult). I unzipped all the tubing and cleaned it and the wires with copious amounts of window cleaner and paper towels. For the cables which were not in zipper tubes, I cleaned the outside of the tubing and as much of the cabling as I could get at the same way. I did not pull the contacts out of the connector housings so that I could get the cable completely out of the tubing. I felt this was going too far.
It was time to move on to the mechanism. I cleaned and degreased it using the methods Ron Rich discusses in his ‘Seeburg Mechanism Guide’. Luckily, my mech was in pretty good shape. It did not have any clutch or cam problems which would have required more than the partial disassembly I did. So I waited for a hot day (you don’t have to wait too long in San Diego for a good day, that’s why I moved here!). Before hosing down the mech, I removed the motor, trip solenoid, popularity meter solenoid, tormat, and pickup. Since I could see a lot of gunk on the transfer arm casing and gear, I removed the magazine and popularity meter so that I could get at everything. I took color photos of the switch plate so that I could identify where the wires I removed went. I got some maximum strength degreaser concentrate, and cut it with about ½ the water it said to use. I put the diluted degreaser into a spray bottle, put the mech out into the sun close to a drain, and started spraying everything that was discolored. Once I had a liberal coating of degreaser on it, I waited for a few minutes, and hit it with the hose, flushing everything out. As soon as the water ran clear, I turned the hose off and took a close look at everything. I saw a few spots that needed a second dose, so I repeated the treatment, using an old toothbrush for some of those hard-to-get-at places. This time everything looked clean, so I got out my air compressor and blew everything dry. I use this compressor for the kid’s bike tires, car tires, and inflatable swimming pool (when the kids were smaller) and for drying mechanisms. It wasn’t very expensive, well worth the investment. Next, I got out my trusty oiler and started lubricating everything, again using Ron’s guide. Note Ron points out several spots that the standard Seeburg lubrication chart misses, so I made sure I got those too, even the hard to get at ones. It’s very important to lubricate the mechanism immediately after you degrease it, so don’t put it off and leave the mech lying around dry. Once I was satisfied with the lube job, I put most of the parts back that I had removed, and checked the appropriate adjustments. I left the magazine, tormat and popularity meter off for the time being, so that I could make sure that the clutch and transfer arm lubrication was adequate. There’s a roller buried down in there between the clutch and safety plunger that’s pretty hard to get at, but I got some oil down there too. I was also careful to apply a bit of bias to the motor coupling when I reinstalled it. I also checked the turntable bearings. Luckily, they were not seized and the rubber bushings were not hard. All in all, my mechanism was in very good shape. It just needed a good cleaning and lubrication. If your machine has not had this done to its mechanism in the last five or ten years, you should definitely either do it or have it done! If you’re doing it, get a copy of Ron Rich’s Seeburg Mechanism Guide.
Now it was time to see if everything worked. The first thing I did was to remove all three PC boards from the control center, and plug it in to measure the AC voltages. I wanted to make sure that the power transformer was okay. It was, so I set up the mechanism and control center on my work bench. The mechanism will plug directly into the control center without the cabinet cable, so I plugged them together and manually energized the play control add solenoid. The mech took off, scanned twice, and stopped. This told me that the motor was working, and that the 24 VAC supply worked too, since the scan subtract solenoid energized each time the carriage hit the 179/279 end of the magazine. I manually energized the solenoid again, and ran it back and forth a few times, looking at everything and listening to it. Working at Seeburg, I’ve heard a lot of mechs, so I know when one doesn’t sound right. Not that I know what’s wrong immediately, but I do know when it does and doesn’t sound okay. This one sounds okay, so I started to manually trip it into play, then back into scan, watching and listening to everything. By doing this, I saw a couple of spots that could use a bit more lubrication, so I took care of that. It goes through the transfer cycle just fine, there is no hesitation on the part of the clutch shifting lever coming out of the scan or play notches, like some other machines I’ve seen. The clutch shifting action is nice and smooth, and there is very little wear on the clutch.
While removing the boards, I noticed that there was a burned resistor on the power supply board. Not a good sign. This is the 390-Ohm (R3113) resistor used to bias the –13 V reference zener for the black and gray boxes. As it turns out, Q3120 was also bad, along with the reference zener diode, CR3110. I replaced all three. This is why I was glad I didn’t plug it in and turn the machine on when I first got it home. With these problems, I could have easily destroyed both boxes. The resistor is a half-watt unit, but runs very warm, since it is very close to its half-watt rating. To be safe, I replaced it with a one-watt resistor. If you’re working on any of the Microlog machines, you should replace this resistor. Once all three parts were replaced, I checked all the electrolytic capacitors, which were all good. I connected the DCC to a variac (a variable transformer, which allows you to bring its output voltage up slowly, instead of just hitting the DCC with 120 VAC). I started with an output voltage of about 50 VDC, and brought it up 10 volts at a time until I hit 120 VAC. I did not have anything connected to the DCC; specifically I did NOT connect the black and gray boxes yet. I wanted to make sure I had a good power supply first, since I did not want to take the chance of blowing out a potentially good black and gray box. The DCC checked out okay. Next, I made sure that the turn-on reset circuit worked. This is a delayed -27 VDC output of the DCC, delayed by a couple of seconds from the main output. It is used to reset the black box. It worked fine.
It was time to see if the system worked. First, I had to replace the mechanism magazine, Tormat, popularity meter, and now-playing indicator since I had removed them when I degreased the mech. After reinstallation, I checked all the pertinent mechanism adjustments, specifically those relating to the Tormat and detent timing switch. Once this was done, I set everything up on the workbench, since I had previously removed the cabinet cabling from the juke to clean it up. I’d much rather work on everything spread out on the bench, rather than have to troubleshoot a problem with either the black or gray box while they are installed in the machine. It’s much easier to get at everything when it is spread out on the bench; you don’t have to worry about any of the PC boards shorting out to the metal parts, for example.
I connected the black gray box, selector and instruction lamp assemblies to the cabinet cable. Next, I plugged it in and held my breath, followed by checking the supply voltages with everything connected. The two supply voltages (-13 and -27 VDC to the black and gray boxes were within tolerance. The +27 VDC supply, used for the trip circuitry, was also within tolerance, as was the Write-In/Read-Out supply, at about +125 VDC. So far, so good. I had the Pricing Programmer Board unplugged, giving free credit, so I made the simplest selection of all, 111. The mech went into scan, and it tripped at selection 111! I did not have the now-playing indicator plugged in, but I could tell it was the correct selection from the label at the top of the record magazine. Feeling lucky, I entered 222, and manually tripped the mechanism, since I had not plugged in the amplifier yet. The amplifier mute/trip relay has to be working in order to reject a record on these machines. The mech went right to 222, and tripped. Wow! Now, if 100 and 133 work, that means chances are very good that everything else will work, since these four selections use all four data paths within the selection system. I went ahead and made these selections, and again manually tripped the mech. They both worked. Next, I made the series of selections I had always made so many years ago while verifying correct operation:
111, 222, 100, 233, 144, 255, 166, 277, 178, and 279
This verifies that the selector and gray box are working correctly. The first four selections (100, 111, 222, and 233) verify that the black box is working correctly, except for the Pricing function. I spent some time probing various points on both boxes. I did this to verify once again that the waveforms published in my ‘The Seeburg Black and Gray Boxes’ were correct. I’m also adding some waveforms for the next edition (the Scan Start board in the DCC), so I wanted to make sure the timing on those were correct, too. I was halfway hoping that there would be something wrong besides the power supply problems I talked about earlier, since it has been so many years since I trouble shot one of these, but I guess the Microlog gods were smiling on me this time. The next thing to do was to make sure that the Pricing part of the black box worked, so I shut the thing down, installed the Pricing Programmer Board, plugged the coin switches into the cabinet cable, and fired it up again. This machine came with the coin equipment still installed, so I inserted a quarter into the top of the rejector. It hung, so I opened up the rejector, cleaned all of the muck out of it, and gave it a shot of silicone spray for the moving parts. After this, it worked. So I ran a bunch of nickels, dimes and quarter through it. The Programmer board included was the ‘standard’ 2/25 cents, 5/50 cents. I ran through the checkout procedure we used at Seeburg (and is documented in my black & gray box book. I didn’t have any half dollars handy, so I just hit the coin switch instead. The Pricing function works, too.
The next thing to do was to reassemble the machine. The painted control panel was back from the painter, and all of the plated parts are back, all nice and shiny. Reassembly went without incident, since I had taken the time to try to organize myself and had taken so many photos. The Parts Catalog came in handy here, too, since it also usually shows the order that things have to be assembled. Each page gives an exploded diagram of a certain part of the cabinet. Each part has a number, which relates to a part list on the facing page. The list gives the Seeburg part number, and the part name. This comes in handy in case you need to order parts. Some of the suppliers simply ask you for the Parts Catalog page number and the item number, using that to locate your part in their inventory rather than the Seeburg part number. The parts catalog usually shows you what hardware (nuts, bolts, etc.) to use to fasten the parts together, how many, whether there should be a lockwasher, etc. However, the catalog shows how the prototype was built, which sometimes varies from what you have in front of you. Here’s a couple of possible reasons: A change may have been made on the production line that didn’t make it into the manual, or the folks on the line didn’t exactly build it the way Production Engineering intended it to be built, and the inspector didn’t catch it. That’s why it’s so important to take a lot of photos while you disassemble the machine. I must admit that I didn’t take enough, for I had some left-over screws and nuts for one area, and I had to run out and buy some different length screws for another area. But the machine went back together pretty easily without any major parts left over. The biggest problem was the spring and cable assembly I talked about earlier. I had to figure out how to get the cable into the spring, since it sits about one quarter of the way down the coils of the spring. Another thing was to make sure that I had assembled the washers, eyelets, and E-rings in the correct order for both ends of this cable. Both sides of the machine are mirror images of each other. The Parts Catalog really came in handy here, for it showed in detail the parts order.
The machine was coming together pretty good. One problem was that the fluorescent lamp for the title strips did not work. I went to the local hardware store followed by Home Depot, even a lighting store not far from where I live. No one had it. It’s a 30 Watt, 30 inch tube. I started calling around, and finally found a specialty store in town that had it in stock. I decided to get another starter, too, just to make sure it would work when I got home. I plugged in the new bulb, and it lit right up.
Next, on to the amplifier. I checked all of the electrolytic capacitors, on both PC boards and in the chassis. I was lucky again, they all checked okay. I removed all four output transistors, and all four driver transistors. I don’t have a curve tracer, but my friend Mike Zuccaro has about three, so I took them over to his place to check them out. They, too, were good, so I put them back in the amplifier. My amplifier has the early version of the bias circuit, the one with the transistor under the heatsink, not the later version using the stabistor. This transistor checked okay too. I made sure that the connections to the bias circuitry had the jumpers connected directly to the PC board as a safety measure were indeed connected and were soldered to their little solder posts. If you have an SHP-series amplifier, I strongly suggest you make sure that these jumpers are connected. Otherwise, you may have the resistors on the driver board burn out on you, and they may take the drivers and output transistors with them. I made sure all of the resistors were of the correct value (not just by reading the color codes, but by lifting one lead and actually measuring the resistance with an Ohmmeter). The emitter resistors for each driver were changed from 560 Ohm ½ Watt to 100 Ohm 1 Watt flame-proof units. You can find these if you look around on-line or in your local electronics store. (Your local Radio Shack probably does not have them). Also, I made all of the continuity checks I recommend in my ‘The Seeburg SHP Amplifiers’ book before applying power. Please note that items g) and h) in that checklist are incorrect. Instead of continuity to the emitter of Q16 and Q26, it should be the collectors of those same transistors.
As recommended in the book, I built the simple test jig. This consists of a line cord with plug, a socket to plug the amplifier line cord into, and a 60 Watt light bulb in series with the hot side of the AC line. This test jig will show you if you have a serious problem with you amplifier, before it causes amplifier destruction. If the bulb lights brightly when you plug the amplifier in, there’s a problem you need to fix before going further. The problem could be something like a shorted transformer, filter capacitor, etc. If the bulb flashes briefly, then it should be safe to power up the amplifier. A very similar test jig was used at the factory for each new amplifier coming off the production line. I only got a brief flash when I plugged in the amp, so it was time to go on to the next step. Since I had no idea when this amplifier was last run, I decided that I should form the electrolytic capacitors in the power supply. This is good for the capacitor, especially if it has not been under power for a number of years, as it builds the insulating oxide film on the aluminum foil making up the electrodes. I started out with the variac set for 50 VRMS, and built my way up to 120 VRMS, 10 volts at a time. I waited about five minutes at each step, so this took a while. While waiting, I would constantly check the heatsink with my hand, to make sure it was not running hot. Much to my relief, it was only warm.
Once I had brought the line voltage up to 120 VRMS, it was now time to set the bias. My old QA supervisor (the person who actually determined why the SHP1 was catching fire) came up with a more accurate method. I recommend this method, although I have heard from a few folks saying that when they do this adjustment, their heatsink runs way too hot. If this is the case, revert to the Seeburg-recommended method. My guess is that some other components in these amplifiers have changed value. Using his method, my amplifier bias adjustment settled right in. At long last, it was time to reinstall the amp into the jukebox and listen to some tunes.
I installed the amp, plugged in the volume control, the jacks from the mech, and connected the speaker wires to the amplifier output terminals. I turned the machine on, and heard the characteristic thump coming out of the speakers as the amplifier outputs stabilized. I made a selection: ‘Hotel California’ by the Eagles, and cranked the volume up. It sounded great, except that the highs from the right channel were kicking in and out. I played with the tone controls, and sprayed some tuner cleaner into the switches, thinking that the contacts were noisy. That helped somewhat, but didn’t cure the problem. I shut the machine down, and swapped speaker wires to try to determine where the problem was. The right channel still sounded bad, so I knew that the problem was not in the pickup or amplifier, it had something to do with the speakers. But when I checked the tweeters when the machine was apart, they both made noise. Granted, I only used a battery to make sure that they put out something. So now it was time to swap the tweeters to see if the problem followed. To do this, you have to remove the front grille, which is no easy to do once everything is back together, since now you can’t lay the juke on its back. I had to remove the front panel to get access to the screws holding the top of the grille in place. The grille is held in place at the bottom by eight or ten screws, and there’s only about an inch or so of ground clearance. Luckily, the screws are hex-head, so a ¼ inch open end wrench works. I only loosened them enough so that I could get the grille off. Next, I swapped tweeters between channels. The wires aren’t long enough to simply exchange connections. Besides, you have to remove the speaker to get at the wires. Swapping tweeters did not solve the problem: the right channel still sounded lousy. This told me the problem was in the crossover. Remember the questionable solder joint on the capacitor? These capacitors are 15 mFd non-polarized units, so I went to my local electronics store to find some. I couldn’t find 15 mFd non-polar, so I settled on some 6.8 mfd non-polar, putting two in parallel to get close to 15. Since it’s such a pain to get at the crossover network on this machine, I went ahead and replace the capacitor for the left channel, too. The machine has been working fine ever since.