Wurlitzer 3700 questions -my first juke!

geezer49

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I recently bought a Wurlitzer 3700 that needs some work. I am somewhat familiar with electro-mechanical pins etc. so I figured I could have some fun figuring how to get this going.
It appears to have spent quite a bit of "down time" in someones basement or garage. The turntable drive belt had rotted and was laying in the bottom of the juke in 5 pieces. I ordered a new belt, needle and keys from Victory Glass and replaced them. Then I found a mouse nest of fiberglass and old pistachio shells inside the bottom assembly under the record carousel. After cleaning it out I tried firing it up and it doesn't quite work. I can press the selector buttons, they latch and the bottom level assemble (in the "mouse house") turns quite a few times and finally times out and stops. The carousel never turns. If I trip the latching switch on the carousel it will pick up a record and deposit it on the turntable, play the record (the amps work!) and return it when done.
I bought and downloaded what I thought was a complete manual from another source (not Victory) but it appears to be adjustments only. No info on theory of operation or what the various switches are used for (run/load/scan or the service switch). I am hesitant to buy another manual somewhere else and just get a second copy of what I already have.
Any guidance/advice will be greatly appreciated,

Thanks,
Tony
 
Welcome to KLOV and congratulations on getting your first jukebox! My first juke was also a 3700 Wurlitzer, still have it and love it to death. After spending a year or so learning the ins and outs of this Wurlitzer style I decided to find the 3800 to house more of my records (almost identical except purple and different selection panel) and by absolute dumb luck I bigtime scored the 1050 Nostalgic model jukebox that rounds out the last Wurlitzer USA jukes before they folded under.

I love these things! I have also found 2 parts machines through the years and would pickup any junk 3700/3800/1050 jukes for more parts. These baby's are pretty reliable when you get them dialed in, and they sound great!

To me, your problem sounds like its in the BO/AC control board, more specifically one of the TRIAC's (There's 3 if I remember correctly). I bet 100 to 1 if you meter out all your Triacs one of them does not have the same values as the other 2. From everything I've read these BO/AC boards are a piece of shit, and every jukebox of the series that I've scrounged up had at least one bad Triac. I've bought the over-voltage h.d. version and soldered them in, have yet to smoke a new one! At one point I considered making some replacement circuit boards for these, the traces burn up and the board gets charred bigtime!

Also I'd bet your turntable motor mounts are weak/sagging/misaligned. (picture below) You'll want to change all 4 of them, under the turntable where the motor assembly bolts to the main shelf. It causes the turntable belts to not line up exactly straight, vibrations and other related problems.

I also added a picture of my 3700 and 1050 - I didn't have a picture online of my 3800 sitting next to the 3700. I'm sold on the 1973 & 1974 Wurlitzer models... they're funky but not hideous and were considered a good workhorse by route operators back in the day.
 

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3700 Noob

Hi Fullthrottle,

Thanks for the reply! You have a couple gorgeous jukes there, I hope mine looks half that good someday. I'll check those mounts, I wouldn't be surprised if they look like the picture. This box is probably close to being a parts machine with all the issues it has but that makes it all the more fun getting it back to decent shape. I spent an hour or so figuring out the basic operation last night, and a couple times it actually selected pins! I hit H6 and it whirred for a considerably sorter time than usual, and when I manually (slowly) rotated the carousel it latched at H6 and loaded the record! Unfortunately I couldn't duplicate it after that. I may pull that lower section and go over it with contact cleaner..maybe all that fiberglass I vacuumed out is causing contact issues.
Another issue popped up.. now when it loads a record the cams never stop in the play position. It drops the arm, then picks up the arm and returns the record to the carousel. In looking at the assembly it appears that a switch should make/break and stop the cam drive until the tone arm trips the switch behind it to release the record..I found the cam brake and while the pad is pretty old it seems to try and stop it if the motor didn't continue to run. Oddly, this was working fine before I started poking around in it... I can't think of anything I did to mess it up..it may just be a coincidence..

Thanks again!
Tony
 
To me, your problem sounds like its in the BO/AC control board, more specifically one of the TRIAC's (There's 3 if I remember correctly). I bet 100 to 1 if you meter out all your Triacs one of them does not have the same values as the other 2. From everything I've read these BO/AC boards are a piece of shit, and every jukebox of the series that I've scrounged up had at least one bad Triac. I've bought the over-voltage h.d. version and soldered them in, have yet to smoke a new one! At one point I considered making some replacement circuit boards for these, the traces burn up and the board gets charred bigtime!

Almost forgot to ask.. Are the Triacs those guys that look like transistors mounted on the big heatsink? There are 4 of them. It has been a long time since I went to electronics training but do the triacs have 3 test points, two pins and the case? (Emitter/gate and Collector?) and meter out the same way you would meter a transistor? Are they socketed or direct soldered? (time to blow the dust off my solder-sucker <g>)
 
Yes, triac looks like a square transistor, three legs and has a little angled metal heatsink attached onto it...

I still think its the BO/AC causing your selection AND arm drop record and pick it back up... I've seen those exact symptoms one my first 3700 and ALL the 3700/3800/1050's that I've played with have had BO/AC problems and smoked Triacs.

Couldn't make selections, just kept picking up records - It was a BO/AC Triac

Record would go onto turntable and then immediately pick it back up and put it away - BO/AC Triac

Even my record magazine motor not turning was a BO/AC Triac.

Also check ALL of your microswitches with a multimeter and make sure they are opening & closing properly electronically and mechanically adjusted correct.

The large spiral bound manual w/ schematics was a godsend for working on these... I believe it costed damn near a hundred dollars but wouldn't have known my ass from a hole in the wall without it. At that back there is a symptom and cause section that is actually very helpful.

On one of my last Wurlitzer jukes had a problem like what you're explaining with the record picked up set down on turntable then immediately cancelled and put back. I watched that brake shoe as you and it seemed to TRY and stop the cam but couldn't. When I would manually stop the cam myself (at the right moment) it would not cycle and would actually play the record. So, I spent days looking for the right cork material, found something that would "make due" and punched out a bunch of round brake shoes and glued one back on the arm... Still didn't work... tried but wouldn't hold enough force on the cam. In the end, what was the problem? BO/AC Triac.

Now its at the point with these that if I were to find another 3700/3800 jukebox I wouldn't even goof around with ANYTHING ELSE until repairing the BO/AC / Triac(s), since it causes so many crazy random other problems you're chasing things that sometimes work, sometimes don't, and over-adjusting everything all over a $5 triac. On my first couple until I pounded this into my head I would adjust everything, finally cave in and mess with the BO/AC, get the juke working close but no cigar, then have to go around and un-eff up all the adjustments that I had messed up while that damn electronic brain box was geeking out and I'm screwing around in the wrong system.

EDIT: The Microswitches on these jukeboxes are also notorious for failure, geeking, sometimes working sometimes not. I found a few that checked when I metered them out but would have a fluctuation after wiggling or tapping on the switch. When in doubt, replace.
 
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The old triacs from hell blues

Thanks again Fullthrottle, I'll check those little suckers out in the next day or two.. right now the wife is on me to get the house ready for my granddaughters birthday party this weekend (she will be 3)
Where is a good place to pick up the triacs? Does Radio Shack stock them or is it best to go to Victory Glass?

Thanks again!
 
Nope, the shack won't have shit.

You'll need to goto either mauser.com / mouser.com - (always get that one confused)

I believe thats where I was getting them... The more I think about it there was quite a bit of research that I had to do in order to figure out what I needed, the first Triac that I ordered was the wrong one and I installed it and didn't know it until later on...

I'll see if I can dig out any of my notes, they'd be buried who knows where they are (unless I had an ounce of forsight and wrote it in my book, doubtful) I could probably use a few more for myself also... They had a few different voltage ratings, the Wurlitzer used a whimpy one, I stepped it up to a higher rated Triac.
 
Found the Triacs!

I still have a whole lot to learn about this juke..I guess that is part of the fun tho'. I couldn't see any square parts with heatsinks until I noticed hinges on the bottom of the component boxes that were mounted on the back panel of the juke.. I unscrewed the top screw on one, the box rotated down, and there it was! 3 triacs on a little circuit board! I removed it but haven't had a chance to meter it out yet. It appears to have a cut etching and a jumper crossing over to another etching. Some kind of mod I guess. A couple of those bigger resistors look like they have dissipated some heat! the board behind them is heat marked.
 
Stupid noobie tricks, part I

As for the mysterious problem that started a few weeks back where the record was placed on the turntable and would immediately reject back to the carousel, I happened to be reading another message in here where someone mentioned a "reject switch" on his juke.. I started thinking (doesn't happen often) and thought:

"huh..I wonder if mine has a reject switch? There WAS a small slide switch on the back that I was playing with...a..few..weeks..back! D'oh"

...yep....
 
congrats!!! i also owned a 3700 americana back in the day. Was actually part of my first big game haul...

all mine needed was a turntable belt, needle/cartridge, and a ton of oiling and cleaning.

there may be a post about it on the old klov....
 
wurlitzer 1050 problems

Hi Guys,

I have recently purchased a Wurlitzer 1050 that has a few issues, i have not worked on a jukebox previously so i am in for a rather large learning curve.

When i first turned on the unit i could get it to grab a record and pave it the turntable by operating the run/load/scan switch. It would then pick it back up and place it back in the rack and then pick up the same record and place if back on the turn table again. This would repeat this by operating the run/scan switch.

This then stopped doing this, now on scan it will continue to rotate the rack and the turntable spins, on load do nothing and on run it will rotate the rack a few turns then just stop and do nothing.

I have operated the coin switches and this seems to do nothing. ( should they make a sound when a credit loads?)
The selector buttons do not stay down when pushed ( so seem to do nothing) although it does operate the switch underneath periodically.

I just need some guidence on where to start, things to check etc and any help would be appreciated, also is there a troubleshooting guide anywhere?

I have also replaced the rubbers on the turntable motor as well as the belts.Would someone have some pics looking up under their turntable on the 1050? just so i can see what needs to be their, have a feeling something is missing although i dont think it is stopping it from starting a sequence of any kind.

Again any help at all to give me some pointers would be greatly appreciated.

Cheers

Corey
 
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