1954 Rock-Ola 1446 Comet Fireball "120" Restoration

The Rock-Ola 1446 is one of those iconic symbols of the 1950's. This baby stored 60 45's and could play 120 tunes, hence the "120". The unit is a marvel to watch as the record magazine rotates, stopping on the selected tune and then the gripper arm pulling the record from the magazine, turning it 90 degrees, placing it on the platter and then lowering the tone arm onto the spinning vinyl. A beefy push-pull 6L6 driven amp takes things from here, belting out the tunes through a hefty 14" speaker and horn tweeter. As you listen to your favorite artist, the animated color wheels turn within the plastic pilasters, radiating out hues of rainbow colors. OK...enough poetic licence...this thing is a mechanical and electrical monster with heaps of relays, solenoids, cams, switches, gears and other hardware needed to make it do its thing!

I bought this at the HVRA annual convention February 12th, 2012. As always seems to be the case when I'm bidding on something I want real bad, another bidder was driving up the price and wouldn't let go. I eventually won it and for a price I think was decent. It's not cosmetically perfect and as closer inspection revealed, definitely not mechanically perfect and a LOT of work lies ahead. As time permits, I'll begin the restoration process and post notes and pictures here. For starters, here are a few pictures of the jukebox as purchased:

The first step is homework and lots of it! Fortunately the jukebox came with a manual including description of operation. Knowing how this thing works will be crucial for the restoration.

Power Distribution Panel Restoration:

The first "hands-on" work will be the restoration of the power distribution panel. This unit supplies 28 vdc to the rest of the unit and powers the various solenoids, relays, and two of the motors. It also supplies 115 vac to things like the turn table motor, lamps, etc. The panel is in rough shape cosmetically and electrically. Here's the power module before restoration:

Further inspection reveals the following:

Here is the finished unit: painted, new bridge rectifier, new power cord, new on/off switch, and new start relay. With the proper voltages now available, restoration of other components can begin.

Accumulator Unit Restoration:

Next up: the accumulator unit. This unit "accumulates" credits depending on the coin deposited. When a selection is made, the unit removes one accumulated credit. When credits are available, the control switch illuminates the "Select" lamp.

Work to be done on this unit:

Here is the restored unit; all coils test good and the accumulator works.

Program Assembly Restoration:

Next up...the program assembly. This unit displays 30 selections per panel and rotates to display 4 panels. This is done with a small motor when the "Program" button is pressed. It also has 4 relays which determine what selector coils can be energized in the selector unit. Here are pics of the motor end and the program transfer switch end:

Work to be done on this unit:

Here is a pic of the motor, disassembled:

After the motor assembly was done I tested the unit out. The program drum rotated but the program coil was making a nasty buzzing noise, like it was a DC coil being fed AC. Looking at the schematic, this coil and relay appear to be relatively useless...all it does is disconnects the Program Change switch while the drum is rotating. I disconnected one leg of the coil and voila...the unit operates properly and with much less noise.

Keyboard Assembly Restoration:

Next up, the "Keyboard Assembly". This is a unit consisting of 3 banks of keys, 10 keys per bank. There are 3 separate SPDT switches per push button. Depressing a key does three things simulaneously: energizes the reset coil in the accumulator thus removing one credit, energizes two-of-six "clapper" or "commoning" coils in the selection unit as dictated by the program transfer switches, and energizes one selection coil that pulls a selection lever which starts the magazine assembly searching for and retrieving the selection. Here is a picture of the keyboard assembly:

The proper function of the keyboard assembly is essential to the proper operation of the unit so I decided I was going into the keyboard once and once only. That meant opening up each switch bank and doing the following:

Here is a picture of a switch bank, laid open. You can see two sliding contact units: one cleaned and one not.

Control Box Assembly Restoration:

Onward to the control box assembly. This should be straightforward and contains: the record load switch, the service switch, the interlock release coil/switch, the interlock trip coil/switch and the cancel relay coil/switch. The essence of this box is to control the magazine and gripper motors.

The picture below is the control box assembly with the 4 .047 uF "bumblebees" replaced, the coils checked, the points cleaned, and the record load switch wired in properly (it had been replaced at some time but connected wrong).

Selector Unit Restoration:

Now things start to get a little exciting...the selector unit is up next...consisting of 120 individual selection coils/levers, and 6 "clapper" or "commoning" coils that control groups of 20 selection coils.Here's a picture of the unit and one picture with the unit opened up. In this photo the following can be seen: commoning coils and contacts, selection levers, and the selection coils.

The following picture is the selection lever assembly...120 selection levers and sliding contacts, two outer copper rails and one grounded center rail. When a selection lever is pulled by the associated coil, the sliding contact connects the outer rail with the center rail. This energizes the start relay and the magazine begins to rotate, looking for the selected record. The contact must be good, otherwise the magazine motor won't start! The other function of the selection lever is to make contact with an indexing contact in the rotating carriage and when this happens, the trip relay energizes (a holding circuit is created for the start relay) and the release contacts flip (causing the magazine motor to brake and the gripper motor to become energized).

The following picture shows one quarter of the selection lever assembly. The outer and center rails have been sanded, along with the sliding contacts. The tips of the selection levers have also been sanded. It's ready to be re-assembled (not the easiest task!) followed by spraying the contacts with "Preservit"

Magazine Restoration:

Onward to the mechanicals. I knew the gripper assembly was frozen and the magazine made a screeching noise when rotated by hand (rusty “keepers” rubbing against a rusty keeper rail). Plus, the magazine was not in the best of shape cosmetically. So I decided to pull everything out to do a thorough mechanical inspection/repair and cosmetic restoration of both the gripper assembly and the magazine. But I couldn’t get the magazine out until I removed the gripper assembly and I couldn’t remove the gripper assembly until I unfroze it. That required the use of penetrating oil and some judicious use of force but I finally got it loosened so that I could get the gripper arm out of the magazine (it’s normal resting place). Here is a picture of the gutted cabinet and the magazine before restoration. My trustworthy helper Booger is supervising in the middle picture.

The magazine consists of 60 sheet metal “wedges” and the records are stored between these wedges. Keepers are installed on every second wedge to keep the records from falling out of the magazine when they’re at the bottom. A large aluminum disk is bolted to the front of the magazine which has an outer track/groove, an inner track/groove, and an inner ring gear. The two grooves determine which direction the gripper arm will rotate when placing a record on the platter. A pin on a pivoting linkage arm rides in these grooves. When the magazine gets to the end of its travel in either direction, the pivot pin is moved from the outer to inner groove or inner to outer groove, depending on direction of rotation. A spring is used as a “one way gate” to keep the pivot pin in the groove it was just directed to. If this spring is not there, or broken (and one was broken), the pivot pin could move back into the groove it just came from, thus erroneously causing the wrong side of the record to be played. I used the good spring as a pattern and obtained some springy steel from a hose clamp. Some grinding, drilling and cutting and voila…a new spring! Here's a picture of the new spring.

One other essential component on the front of the magazine…the reversing switch stops. These are mounted on the outer circumference of the aluminum hub. These stops engage the reversing switch pivoting arm at the end of magazine travel and actuate the reversing switch. The reversing switch assembly consists of 4 DPST switches and performs the following functions: switches the indexing contacts and reset solenoids on the carriage from one side to the other, and switches magazine motor armature contacts to change the direction of rotation.

Cosmetic restoration of the magazine was as follows:

Here's a picture of the painted and labeled magazine, and the painted keepers.

Since I had the magazine out, it made sense to do some cosmetic work on the backside of the cabinet. This included installing new mirror segments on the back panel, and fabricating and installing a metallic silver cloth covered panel behind the wheel. I think originally this was just painted blue. Not much is actually visible but it's a nice touch. Here's a picture.

Gripper Assembly Restoration:

This is the assembly that plucks a record out of the magazine, rotates it 90 deg one way or another, lays it on the platter, and then ungrips it. I think it is called a "Geneva" mechanism. Anyway, it's neat watching it in operation. I disassembled all the components, degreased, painted exposed surfaces hammertone silver, lubed, and reassembled. Heres a picture of the components just prior to assembly.

Tone Arm Assembly Restoration:

Next up, restoration of the tone arm assembly. The assembly contains the tone arm/cartridge, the grip cam limit switch, the "end of play" tone arm switch, and an interesting feature that prevented customers from banging the jukebox to force the arm back to the beginning of the record to get a free repeat play. This would cause the tone arm switch to close and the record would be returned to the magazine. Here's a picture of the mechanism.

The following work was performed:

The Magazine Motor, aka Adventures in DC Motor Land:

The next step was to restore the magazine motor. I resurfaced the armature, lubed it, and tested it on the bench. The motor turned sluggishly and pulled over 2 amps, well in excess of the design of .5 amps. I decided at this point the armature needed undercutting so I devised a rig using my Meccano set from my childhood days (thanks Mom for not tossing stuff like this out!). The spacing between armature segments is small and I ended up needing to procure some thin cut-off wheels (.015" vs the standard .025" available from Dremel). Here's a picture of the rig and it actually worked well!

While the undercutting worked, unfortunately the motor still didn't, pulling excessive amps and getting hot quickly. I concluded I had a short in the armature winding and researched rewinding it myself. I could never figure out exactly how it was wound so I decided to unwind it to figure it out. The death knell was the very fine wire used and it simply broke as I tried to unwind it. On to plan B: I hit eBay and saw listings for much newer Rockola motors, like the 490. They looked similar but would it work? For $30 plus $10 shipping I decided to find out. The motor ended up having a slightly different footprint and to make it work, I fabbed an adaptor plate from 3/16" plate which worked well! The drive gear was different but all I had to do was swap gears. I also had to change the position of the older gear on the newer shaft but that was a simple matter of drilling a new hole. The new motor had only two wires (for the armature) since it used permanent magnets (the original had two leads for a field coil). All said and done, the retrofit worked perfectly! There were some other glitches I had to contend with but in short order, I now had a magazine that would rotate.

Here's a pic of the newer magazine motor installed:

The Amplifier

At this point, I decided to tackle the amplifier. Overall, the best way to describe it was that it was a mess. It had a broken 5U4 socket, a missing "standee" resistor (used in the 6L6 cathode circuit), a missing tone control, and a lot of disconnected wiring. The wiring harness was also badly deteriorated. Here are pictures of the topside and underside of the amp before restoration:

Since I had chosen to use a magnetic cartridge, this required the use of a pre-amplifier. I chose the popular 12AX7 and rather than punching a new hole in the chassis, I simply located the 9-pin socket where the standee resistor used to be. The following attitional work was performed:

Here are pictures of the chassis after restoration:

The Carriage

The Turntable

Final Assembly and Troubleshooting

Cosmetics

Cosmetic restoration consisted of the following:

The addition of color wheels was a must! These slowly revolving wheels add significantly to the visual appeal of these jukes. Apparently some machines didn't come with animation wheels, some came with animation wheels but no motors, and then some came with rotating color wheels. I managed to find a decent used cylinder set and a pair of motors. However, I had no idea how the motors were supposed to drive the wheels nor could I find anyone who knew so it was time to improvise. The following photos show the components I used. It's basically a cut off bolt with a washer stack covered with cork to provide a drive surface. The motor was mounted at a right angle on the outside of the light stick and the washer stack attached to the motor shaft. THe cylinder simply sat on top of the washer stack.

Next was to replace the pillasters. The pillasters that came with the set appeared to be a home-grown improvisation and were better than nothing. However there are some high quality reproduction pillasters out there and I bought a pair from "vcoke44" on eBay. THese are translucent white heavy duty plastic and although don't look exactly like the originals, the look pretty darn good!