Rowe R74 Jukebox Rebuild

Recently purchased a Rowe R74 Jukebox great prince but in terrible conditions, I generally deal with PCs and Arcade Machines so I can use all the help I can get, so far achieved following

* Managed to open jukebox (locks had been drilled out already) but spring loaded mechanism was locked)
* pulled out and sprayed down entire record playing mechanism with electronic cleaning spray (non conductive), have also air gunned it down to dry the cleaning solution and remove copious amounts of dust and particles accumulated through ought years of storage.
* All records have been removed for cleaning
* checked one fuse located in top portion of the machine (Song selection mechanism) found to be in working conditions
* cabinet has been carefully cleaned inside and out and all dirt and grime removed
* Record playing arm disassembled cleaned and counterweight balance system rebuilt as it had a cross threaded screw
* New SHURE needle purchased and installed
* Amplifier confirmed to be working and has been reattached to the turntable.
* Purchased and printed out Service and part manuals for Rowe R74, currently studying them.


Issues so far

* song selection mechanism after applying credit (through credit button) allows selection of song but appears to have no effect whatsoever on the turntable mechanism, already cleaned and both data cables, turntable mechanism behaves as if none of them are connected

* there is what appears to be a large relay both on turntable mechanism and amplifier mechanism, both appear to be defective and upon wiggling alternate in between clicking madly and not clicking at all, depending on how exactly they are wiggles turn table can be made to spin and Record carousel can be made to spin as well

* Record selection arm appears to be working correctly can be mad to load and drop records into position without any major problems although Record player arm mechanism half of the time drops to quickly and catches side of record therefor lifting the record back up and pushing it off position

* magnetized switch turns on and off correctly to activate amplifier (most of the time) sometimes have to fiddle with it a bit before amplifier turns on but it has to do with the previously mentioned relays and not the electromagnetic switch.

adding a YouTube link to show operation so far, any and all advice GREATLY Appreciated. As suggested earlier have absolutely no experience whatsoever in jukeboxes and only rudimentary knowledge (although best intentions) in electronics

https://www.youtube.com/watch?v=cTd5xt8da9s&feature=youtu.be

I may be contacted directly at 780tech@gmail.com

Thank you

From your video it is obvious that the arm is binding. These are excellent changers and can easily track at 2 grams ( I have two MM-1 hideaways on location) .

Some things to check:
Lift the tonearm assembly up and out of it's pivot bearing. Flip the lever that follows the cam that lifts the arm off a record and carefully lift the whole assembly straight up and clear. Be careful not to break the tiny pickup wires that are solder to the socket on the side (weak design). While at it remove the two wires attached to spade lugs just forward and under the arm. These are the 'no record reject". They just add drag. Trace them back and cut them off.

Next, clear out all the old oil and grime from both the tonearm bearing and stud. It may be necessary to remove the bearing from the platform and flush it with degreaser, stripper, etc. Clean/degrease the stud too. Add several drop s of a light oil (10wt) to the bearing and stud before placing them back. Be careful to be sure that arm posts that ride the cam are centered and the lift lever is flipped back to it's normal position. Check that the pickup wires are properly dressed in a semi-circle and don not impede arm freedom. In play position, lift the front of the arm with the back of your thumbnail and carry it to trip-off point. It should not bias either inward or out.

When in-use the arm assembly tailpiece -must- clean the lift lever by around 1-16th inch or slightly greater -but do not exceed 1/8th in.

Check the profile on the cam that lifts the lever and arm for a worn notch. Repair with heat shrink tubing over that cam if a notch is observed.

Check that the bottom of the cart is clearing the gripper bow when it is on the left side. Only around a 1/16th is necessary.

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The chattering relays may be fixed by removing them and cleaning their prongs with contact cleaner and a tooth brush,. But this problem may not be as it appears.

There will no-doubt be a number of problems you encounter along the way and, since this is you first machine, a manual is a must. Try here:

http://www.alwaysjukin.com/items/servic ... s/list.htm Or: http://www.victoryglass.com/

Rob/NYC

will follow your advice, as stated already purchased digital copy of manuals.. and am attempting to decipher them as we speak, will keep you posted.

One more question, I did suspect that the relays are mounted in a socket but haven't dared try to pry them out, out of fear they may be soldered, are both of them in fact socket mounted ?

Thanks

Tony

Tony, any "ice cube" type relays used in jukes from the mid-sixties-on are plug-in. In certain positions the coil impedance of the relay is important. So it is a good idea to check the relay model# against that listed in the manual.

When I mentioned that there may be more involved here is that relays this old most likely need to be opened and have their contact points cleaned and de-pitted for reliable operation. In commercial service I check the relay points every few years and service as needed.

I suggest reading Ron's remarks about "check switches" and "contact points" since this pretty much sums-up the techniques for dealing with these relays too.

Rob

Good Evening Gentleman.

As recommended removed both relays both on turntable mechanism (Red cover) and Amplifier (Yellow cover)

for reference tried to copy the blurry half erased numbers off them to the best of my ability (may have some digits wrong)

Guardian Electric
45305 RED (A410-364874-13)
Had quite filthy Leg contacts, used a new can of Radio Shack contact cleaner (ran into a gentleman at Radio Shack whom works on ham radios and he recommended I use the variety that leaves no residue)

Sprayed the legs and cleaned with a toothbrush, both the socket connector as well as the relay contact legs also sanded very gently with a fine 320 grit sandpaper until the legs were looking shinny and new, upon removing the case contacts inside looked perfect so I didn't touch them

Guardian Electric
9253-A YELLOW (A410-364473-23)
This one had already been messed with in the past and the yellow cover was cracked, I suspect allowing more air in and therefore the contacts on the inside were grimy and green.

Sprayed and scrubbed with a toothbrush outer contact legs and connector socket also gently sanded connector legs although they were pretty clean the inside however was pretty bad contacts were a mixture of black and green, I ripped off a tiny piece of 320 grit sandpaper and gently slid in between contacts (one way and then the other) on both sides of the switch sanded until I was satisfied the contacts should be clean again.

Very satisfied with the cleanliness of my contacts put both relays back together and into their respective sockets.

---------------

Aftermath

In all fairness I have no idea what the yellow relay does on the amp but since the amp is working I am assuming the relay is too.

The red one however is a completely different story, upon reinserting shows same behavior associated with different actions of the jukebox weather it is making the turntable spin or the record carousel spin requires wiggling it around, obviously this may indicate a problem with the socket cables or contacts (OR could still be a problem with the relay)

Have had little luck locating new replacement relays any and all advice appreciated.

Kindest Regards
Tony

TOny, the relay on the amp does two things: Mutes it at al times other than when the stylus is on a record and applies a voltage to squelch the automatic volume control so that volume slowly increases at the start of a record. this will be a bit more noticeable on a low cut (quiet) record.


I am a bit confused about the so-called "red" relay on the mech. Typically this relay controls the mech as you describe, however, this is usually a DC relay and red cover relays are generally AC. AC relays have a lower coil impedance than DC for a given coil voltage. Since this machine falls into a gap in the era of my experience I'm not much help here. Using a DC relay in an AC circuit will cause it to chatter wildly (more like a buzz).

What I suggest:

-Look at the case of both relays, the type of coil current will be spec'ed.

-Check the manual and see if that relay is fed AC or DC.

-Use an ohmmeter to check the coil of both and compare them.

If the "red" relay has solid continuity and is the proper type for that position, the socket contacts are likely the problem.

Rob

The numbers came off the cases but I will take photos tonight and phost them

thank you

Tony - I was reading this thread and one thing you said jumped out at me:

I ripped off a tiny piece of 320 grit sandpaper and gently slid in between contacts

I would definitely avoid doing this to any more contacts! Using something that abrasive destroys the point surface and creates a thousand little grooves that create a microscopic lightning storm every time they touch. This almost ensures having a problem in the future with them.

For a quick lesson in cleaning, read Ron's sticky on the subject. And speaking of Ron, here's some fair warning - if he sees this you will most likely be the next in line for one of his infamous "wet noodle" lashings!

Nelson

Hi All,
Only WurliTzer BRANDED (part number on it) relays signified red as DC and white as AC relays. This gets confusing, if another brand of relay is used.
I have seen Seeburg numbered relays in red, orange, clear and blue covers, all with the same part number stamped on them.
As for the "wet noodle"--it got soggy, and works no more-----
Ron Rich

Hello Tony,

Welcome to the forum.

From your video I can hear clicking from the transfer motor, this will be that the fibre gear on the open gearbox has a missing tooth.

You will need to replace the transfer motor or replace the gear, the company that produced these motors offers a kit to repair/replace the gear.

I suggest that you do not use any form of spray on the jukebox, instead strip down the parts and clean with soapy water (not on electrical items) to remove old oil and grease. Us engineers have our own ways of doing things, unlike other jukeboxes keep any lubrication to a minimum and only where indicated in the manual.

For example the gripper bow assembly only needs high melting point grease in either end of the trunion casting. If you added any lubrication on the nylon gears this would only cause wear and would make the operation slugish.

Your tone arm needs to be checked to see if the tonearm wires are catching anywhere.

I suggest that you check all of the adjustments on the mechanism as per the manual working through from start to finish, checking for wear on any parts as you go through these adjustments.

The plug in relays on the side of the mechanism, on the search unit and the mute relay on the amplifier are all the same type and are interchangable.

If your side panels on the jukebox have cracked or damaged front edges, check the rear edges of both side panels, if these are in better condition swap the side panels over (old operators trick).

Please let us know how you get on with your rebuild.

Regards
Alan

Alan Hood
ami-man
UK

Good Morning Gentleman.

First and foremost... apologies to Ron for the usage of sandpaper (seemed like a good idea at the time)
Would still like to replace both of these relays if anyone can point me in the right direction.

I have checked and rechecked the wires to the record player arm and agree there would appear to be some kind of drag there but for the life of me cannot figure where exactly, over the weekend I will work on it a bit more (would help to know exactly what route the cables were designed to follow to begin with) as the jukebox has already been tampered with by someone else in the past it is impossible to say they are going the right way.

Regarding the relays:

Schematics on plastic casing and voltage parameters "APPEAR" to be the same but I didn't want to take a chance so I kept them in their respective places in particular because they have different part numbers, as promised I have uploaded photos to my webpage for easy viewing.

http://www.780tech.com/r74/

As for disassembling the entire mechanism and washing the parts with soapy water (may be slightly above my pay grade) but we will see what we can do, I will also look into the Gear kit availability over the weekend.

By the way if anyone lives in this area please let me know I would love to have someone with some real experience in the matter take a peek at it.

Thank you again, will keep you all posted.

Tony

Tony,
Those both appear to be"nominal" 25 volt DC relays. Your local electronics store should have a NTE cross-over replacement in stock.If not, PM me as I do--
Ron Rich

Tony, washing the entire mech is not absolutely necessary, but thoroughly cleaning out and re-lubing the tonearm pivot and stud are.

BTW: In your third pic I see that the lift lever is flipped forward. I assume you know this must be in the back position for normal operation. Also, check that it actually clears the tail of the arm assembly when in play mode.

Rob

OMG, NO.. I actually never realized it was supposed to be flipped back, Facepalms, would this have any effect on how anything works ?

I am assuming the lift lever is this ?



And I did pull out the tone arm mechanism and clean the pivot and the inside with a q-tip. I also sprayed the inside (Don't be angry) just a tiny bit with WD-40 but have now been told several times to use a certain oil I intend to get over the weekend. there are two tiny cables going to upper contact portion of the tone arm that have been detached form their contact but seem to affect not the sound (not sure if I did it or it came like that) will take photos of these next.

Thanks

The lift lever is that metal piece with the stretched spring laying next to the reject button. That raises-lowers the arm/stylus. I took another look at your video and that lever is in the wrong position. That is why the stylus (what is left of it) doesn't set down correctly.

Since the previous owner has probably 'Gepetto-ed" the mech, you'll need to go over all the adjustments. Just check them before trying to fix things with adjustments.

One of the "joys" of forensic troubleshooting is discovering the layers of f-ups others made, One mistake trying to fix the previous one.

Rob