The jukebox gods hate me... (Rowe MM-6 Rebuild)

foxtrotxray wrote:I'll grab a video of the tansfer arm - NO RECORD SLAP! Muhahaha!)

Well, my elation ended quickly.

Found the wiring/scan issue - while I was re-tying the wiring harness, I must have accidentally disconnected one terminal from the detent coil - which is activated when the magazine is scanning. Plugged that in, and let the mech cycle through about 15 records.

After 5 or 8 of them played (mix of both A and B sides), the transfer arm returned to hitting the records down. Owell, I was hoping that I had gotten it.

Had to adjust the tone-arm cam, as sometimes the needle wasn't dropping on the record completely, but that was an easy adjustment.

Now I'm finishing up putting the selector back together, and had a question for you guys -


Should other caps (specifically these pictured) be replaced? Should I worry about it? There are three there - the big one is for helping to arrest sparks when the coil is cut on and off by the relays. (The other two I'm not 100% sure where they are in the circuit..)

One of the relays in the keyboard determines the duration of the punch. It is an electrolytic though I can't remember what the value is. For home use, if the selection system works it is not imperative that the caps be replaced. If this were a commercial restoration or for sale, I'd replace them. I believe that model still had a clear cover over the relays in the KBD.

As for the flapjacking records. understand that if the gripper is set properly it is the center of the record that is flexing and hitting the table and making that ringing sound.
Manually get a record to the point where the gripper has flopped down but not begun opening and releasing the record. With power off and turntable still, the record should not be touching the table. A 1/16th inch clearance is enough. This is necessary to reduce the amount of "Rowe Wear" as I call it. That is where the gripper stops the record while the table is turning and causes a series of scalloped, concentric patterns on the disc. This doesn't do any real damage, but it can sometimes cause a slight scratched sound on quiet records. The record should lowered that last fraction of an inch as the "V" in the gripper ends opens and allows it to land on the table.

BTW: I was surprised to read of the fractured weld on the belt-roller support. I haven't seen that before.

Rob

Rob-NYC wrote:One of the relays in the keyboard determines the duration of the punch. It is an electrolytic though I can't remember what the value is. For home use, if the selection system works it is not imperative that the caps be replaced. If this were a commercial restoration or for sale, I'd replace them. I believe that model still had a clear cover over the relays in the KBD.

Okay, I'll leave them be for now. I AM having an issue with the selector - but it's a mechanical issue, not electrical. (The relays do have the cover, I took it off for that pic.. Both relays work good so far. I have NOT checked the gap on them yet.)

The issue I'm running into - and I was hoping that reseating the coil would have helped - is that sometimes when the selector coil is energized, the bottom row (numbers) won't stay latched. Press it in, and release it - you can feel the button 'hold' slightly as it feels like it *partially* caught on the latch, but then it pops out. The crazy thing? Holding the latch in with your hands does NOT affect this. This, along with several slow-moving buttons, is telling me I need to take apart the latches and 'rub switches' (what I call the perforated board with the metal contacts.. I'll have to look in the manual and see what they're actually called!) and give it all a good cleaning. Having never taken these apart, this will be an adventure.

Rob-NYC wrote:As for the flapjacking records. understand that if the gripper is set properly it is the center of the record that is flexing and hitting the table and making that ringing sound.
Manually get a record to the point where the gripper has flopped down but not begun opening and releasing the record. With power off and turntable still, the record should not be touching the table. A 1/16th inch clearance is enough. This is necessary to reduce the amount of "Rowe Wear" as I call it. That is where the gripper stops the record while the table is turning and causes a series of scalloped, concentric patterns on the disc. This doesn't do any real damage, but it can sometimes cause a slight scratched sound on quiet records. The record should lowered that last fraction of an inch as the "V" in the gripper ends opens and allows it to land on the table.

I'll check this. I've been watching it closely - it will still occasionally NOT flop a record down, and when it doesn't, this is what happens -
The arm picks up the record, and pulls it forward.
It pauses as it hits the side select pin, then starts to rotate.
The far side of the record falls faster - as it rotates, and right before it hits the table it seems to hit the end of the slack in the gears.
Hitting the end of the slack the edge of the record slows considerably to be gently placed on the table.
The difference with a slapping. record is that it never seems to hit the end of the slack in the gears, so it hits full-force down.

In either case, I'll check measurements - I believe that one of the standoffs IS UNEVEN - it looks lower that it's mate on the other side of the table, so this could be causing the noise, as well.

Rob-NYC wrote:BTW: I was surprised to read of the fractured weld on the belt-roller support. I haven't seen that before.

[/quote][/quote]
Thanks Rob - Yeah, I was too. Though, with the old guide, you could hear it rubbing the edges of the records, it may have been doing that for a while, and the previous owner/tech tried forcing the guide by bending it upwards. Either that, or something fell on it. Strange, but I like the new one a lot better. Like Ami-Man mentioned, the replacement has a rubber stop (the old one has a clear plastic stop), and the rubber is sitting high and the transfer arm hits it with a silent knock, instead of with the 'click' the plastic one caused.

Sorry guys, I ramble. I'm enjoying the hell outta this.

The "official" way the flopping was dealt with was to replace and compress the wave washers on the shaft next to the tonearm cam on the left.
Since the cam must be removed it will have to be re-timed -nbd but I never considered the problem worth the trouble and this fix only lasts a year or so in commercial service. It also adds a bit of load to the gripper motor...
Rob

Rob-NYC wrote:The "official" way the flopping was dealt with was to replace and compress the wave washers on the shaft next to the tonearm cam on the left.
Since the cam must be removed it will have to be re-timed -nbd but I never considered the problem worth the trouble and this fix only lasts a year or so in commercial service. It also adds a bit of load to the gripper motor...
Rob

Interesting. I may try it, but.. Like you say, it's likely not necessary -

While adjusting the tone arm cam (I had it a little *too* far forward, so sometimes if the transfer motor stopped quickly, the needle wasn't dropping completely. Was an easy fix.. I didn't tighten it at that point (was before I read your post here), but now - no slapping. Strangely, it's setting the record down rather smoothly.

That, added with an odd issue that both STARTED and RESOLVED ITSELF while I was working on other things - the scan reset coil decided to stop firing. After about ten minutes, before I even started to look at it - it started working.

THEN, just now, in between working on other things (specifically, when I was adjusting the tonearm cam), one of the audio wires cam unsoldered from the plug, so had to re-solder that. Something else is bad, though, as still no audio outta that channel. Argh.

For everything I'm getting done, little things keep popping up.

On another note -
Do ANY MM5/MM6's exist where the metal title strip indicators have NOT ripped off and then been patched with glue or tape and made to look ugly?!

Well, I found one reason why my amp was sounding horrible -

I mentioned earlier that the tonearm wire had been re soldered. I fixed it at the plug, and as I was re-installing the tonearm assembly a wire came off one of the cartridge pins. Get it soldered back up, and noticed something -

When both channels had a signal, it was extremely tinny, no bass. Disconnect one channel, and it would sound better, fuller. (Though, admittedly, only on one side.)

The tone-arm wire is not original to the juke, so I'm guessing that when it was replaced, the tech reversed leads on one channel. Since the amp does that cross-channel thing for the bass speakers, reversing a channel caused them to cancel out.

The juke doesn't sound half-bad now! It's still not *great*, and has the strange soft squeaking, but it's enjoyable now, at least.

Quick update, in case anyone cares.

Money meter is installed. Out of the possible locations, I liked it here the best:


I reset it back to $0, and it's connected up waiting for me to close the lid and start putting money in. (Ignore the stop light in the background.)

If you look, you can see a piece of wood there, up and to the left. I started looking at the lights in the selector. Apparently someone couldn't find 26" florescent tubes, and instead of waiting to find one, they modified the sockets - the bottom light had two pieces of wood put on both sockets to narrow them down, while the top light had ONE socket moved in 2 inches. While it's not much, it IS noticeable looking on the outside of the selector. Now, on my old juke, we had red sleeves around the lights up there and in the door (the title page light was blue..), and it made the juke really stand out. Now, I'm thinking of going the non-authentic way, and putting red LED strips back there. Save power, save plastics from fading more, and not have to worry about fixing whatever else was done to the sockets to support a T12 bulb. (Original was T8, I believe!)

About to take the selector out again, and see why some buttons aren't catching - some of the buttons look like they've been abused, so I'm sure that things need to be cleaned.

--Mike

An update..

The mech is just about complete - as mentioned in my other thread, taking care of some small issues now on the mechanism itself.

On the cabinet, the whole outside was cleaned (horrible, horrible nicotine), and I've started yanking out the florescent tubes. They were mismatched and sized wrong, a hack from previous operator days. Here it is, lit up with the old lights -


Coin acceptance is all set up, and I've started paying for songs played as I work on the lights and cabinet.

Also took time this morning to thoroughly clean the other (original) motor, to re-oil and test out at a later date.

Looking great.

Some machines get lucky.

Rob

I'm going to start out this post by saying -
I know many of you probably will NOT like it. However, it's my juke, and I don't care. Seriously, I have a thing against UV light and florescent tubes - I've lost a lot of plastics and art to CFLs and other florescent tubes in various machines and such, and I could tell that things on this have faded/discolored considerably already. (Not visible in the picture, but the red plastic around the selector? It's lighter - faded - on the top and bottom.)

Since the previous owner gheppeto'd (..did I spell that right?) the lights on the juke already, and required a complete rewiring if I wanted to get it back to factory (somehow he wired one starter into two bulbs. No friggin' clue how it worked and didn't burn up / blow up), I decided to go a different route.

The MM6 I had back in the late 80's, early 90's, my father put in some colored sleeves around the tubes, to 'snazz it up'. His words. I never knew this wasn't part of the original design, and liked how it looked. Even to this day. So, I followed suit, but used newer lighting -

Note that digital cameras don't like the monochromacity of LEDs.. The selector lights are NOT that bright, and the fade off at the corners is not noticable in person at all. Uses under 40% of the power the tubes used, and no UV light to discolor. Took only a weekend for most of it - the longest time consuming was figuring out HOW to mount the lights.

Now, work on this will pretty much stop for a while. There are two things left that I need to do -
(1) Get the Amp rebuilt, and
(2) Clean out the selector buttons.
However, as my Twilight Zone's playfield is scheduled to arrive today, and I have two business trips taking up all of September and first week in October, my time's going to be fragmented, and focusing on the pinball. I'll be USING the juke to play music as I work, so it'll get a workout.