Phonoland

Rob, sorry about the name mix-up, I thought this was a follow up question from Ron.

Around the time of this R87, I used to design microprocessor based computer boards, so I am familiar with designs of this era, but I wouldn't have done it the way Rowe did. It looks to me like a bunch of analog designers were just getting into digital design and so their techniques are a bit strange. They use transistors, diodes and quad comparator ICs to strobe various inputs and put them onto a common data bus. There were plenty of bus driver ICs available that did the same thing, and would take fewer discrete components and make more sense to people troubleshooting today. It took me quite a while to figure out what is going on, especially without a schematic. I had to put the PC board on a copy machine and then follow the traces with a pen to reconstruct parts of the schematic. What a pain!

The one thing that was clear to me early on, is that the problem had to be somewhere between the Home LED on the Mechanical board and the diode next to Q116 on the CCC. The other side of that diode is a shared data line. So if other things tied to that same data line, like the Most/Least Favorite switch, worked, then the microprocessor was fine. I also doubted it was a memory problem because I could read out Most and Least favorite on the display. Yes, only a segment of memory could be bad, but that was a long shot.

One thing that bothered me about this design, is that the Home and Index signals both drive a transistor on the CCC. The resistor on the base of those transistors is on the Mechanical control board, while the transistor is on the CCC board. That basically exposes the base of the transistor to any noise on the cable harness. I would not have done it that way.

I have one woofer out and yet this machine sounds as good or better than any I have worked on. I really like the light-weight tone arm. It looks what you'd fine on a high end turntable, especially when you compare it to, say, a Rock-Ola of the same years.

By the way, does anyone know why Rowe swapped the tonearm around on their machines and put it on the left? It seems so strange to me to have the record spinning into the head of the tone arm, with the cartridge turned around. as opposed to the cartridge being dragged behind a tone arm on the right like on 99% of the turntables out there. Just curious.

As one of my kid's used to say (especially when caught with his hands in the cookie jar) --"on accountabecause" !!
Ron Rich

Now that the R87 is fixed, I need to load it with Disco tunes, hang a glitter ball and pull my polyester suit out of the mothballs.

.......I am familiar with designs of this era, but I wouldn't have done it the way Rowe did. It looks to me like a bunch of analog designers were just getting into digital design.....

Jukeboxes are in a somewhat odd category that can be described as 'prosumer" in that they are designed for customers who will 'go under the hood" but often not have formal electronics training.

In these situations continuity of design works for both the company and buyer. But it is not without pitfalls. The first Rowe CD machines in 1988 used a scaled down version of the wire-cage magazine that was essentially the same as they had used since 1956.

These magazines and the guide fingers that centered the record as it returned scribe light markings on a record. these are on the surface and don't affect the playing grooves (we called it "Rowe wear") on CD's these marks interfered with the optics. Rowe rushed out a skeletonized magazine which solved that problem but does make the machine more prone to spilling the disks if it is bumped around.

Amps are another area where Rowe kept the same concepts (and design engineer ) for decades. The tone shaping, AGC and RVC are conceptually the same from MM-1 through the CD era. The designs are highly refined and reliable, but also big and heavy compared to a modern all-digital amp.

As for the left-hand tonearm. I was told that this was designed for the L series which still had a visible mech so AMI and their new owners wanted something unique. They didn't realize that Seeburg's LPC would obviate mechanism showmanship in a couple of years.

That 1100 mech series also had a lot of growing pains. By the "N" it was pretty well fixed.

FWIW: A Rowe JEL was the first jukebox I played (I was 6). It was new. My selection was "Sherry" by the Four Seasons...

Rob

Rob,

I have had an AMi Model K for over 35 years. It's a top of the line JEK-200 with a WQ-200 wallbox. It's a wonderful machine, but has some quirks. The "3-channel stereo" wiring is bizarre, and it sometimes get moody when making selections... the wiper arm on the mechanical memory misses the peg and goes around again and again until it gets it. Then later, the problem mysteriously goes away. As with most AMi machines, the audio quality is great (when everything is set up just right). But the stereo amp is a monster with those hard-to-find tubes (6973?).

The tone arm is on the right on this one.

Someday I'll relate the story of how I came to own the Model K, it's an interesting story. But I swear to you it was delivered to my house laying down on the roof on a borrowed blue AMC Hornet station wagon... the roof was caved in from the weight when it arrived. I still have remnants of blue paint on the back of the jukebox. A word to the wise. Don't put a jukebox on the roof of your car.

The biggest problem I've had with the "K" is that someone before I got it did some modifications that were awful and hard to find.
One was a wiring mistake when they replaced the mute relay, that caused the amp to run in low power standby all the time. The audio was always weak with AC hum. I kept thinking it was a component failure and didn't think to trace out the wiring to see if it matched the schematic. This took literally years to figure out.

The other problem, and somewhat easier to find and fix was when, I guess, it got out of alignment and wasn't pushing the memory pins properly. Rather than adjust it correctly, someone simply bent the wiper arm so it hit the pins (usually). Eventually I noticed it was bowed and straightened it out, which made the jukebox play the flip side of the previous record. I kept trying A-1 and it was playing K-20, it took a while to figure out. I kept thinking it was a problem in those stepper wheels. This is likely the reason it sometimes gets moody and misses the pins now. But it's fine 95% of the time.

I can't recall the first time I played a jukebox, but when I look at the selection keys on an early 60's Seeburg, they look really familiar to me as though I remember them from my childhood. If I had to guess, that'd be the one.