Gripper motor RO 436

[kevwilde]

Hi guys and gals,

I'm working through a similar issue as ollie described in one of his posts.

Current state:
- credits are accumulated correctly
- lockbar mech correct locks pushed in keys
- write in circuit correctly registers
- gripper arm moves slightly (3mm) then stops and the whole sequences does not continue

Carousel motor freely moves around when turning the motor manually

But the gripper arm motor feels stuck, using some leverage I can turn the gripper motor counter clockwise and bring it back into the stand by position (opens up #1 MS).
But after trying to run the sequence after the write-in, the gripper arm only moves a few millimeters and then the motor feels locked up again.

After this I, SCAN will not rotate carousel and I have to manually flip the interlock to get scan to work again.

Should I normally be able to fully control the gripper arm's entire movement by manually revolving the gripper motor?

What could be my next step?

Kind regards,

Kevin

[Ron Rich]

Hi Kevin,
From what you have written, it appears to me the gripper, itself, has problems--I appears as if the read out sensor is on a selected pin, and the gripper itself is stuck. Read the (red pinned)"sticky above", on grippers-- Ron Rich

[kevwilde]

Hi Ron,

Your analysis about the read out sensor being over the selected pin is correct. The entire sequence halts after the read out sequence has finished (something I forgot to elaborate).

As it is not possible for me to put the gripper arm in an upward position, I'll open it up, clean and relubricate it. I'll read up on the topic about lubrication before buying my lubricants.

Thanks for your advice!

Kevin

[ollie]

Hi Kevin.
You are probably doing it more correctly than I, by disassembling the whole thing and cleaning it..But,

I seem to have gotten the Gripper mech/arm to finally move freely by:
Cleaning it out with Isopropyl alcohol (commonly called isopropanol) then I took a 2000 grit sandpaper and
polished the surfaces of the piston and such.. cleaned it again once again from debris and dirt with the alcohol, then I lubricated it and worked
the oil in there , Ron has the best ideas.

Tip,
you can remove the gripper motor completely (3 screws) and
make it a lot easier to wiggle it around manually , you can also get it to open up slighly in a certain position (the arm) and get oil in there thru the "crack".
A had a rag/paper towls wrapped around the mech as I was doing this, to prevent too much of the alcohol/oil to soil the outside.
Naturally, Please remove your records first as they sure will be toast if you spill isopropanol on em...hehe!
That´s how I made it better at least..not sure if it´s the "perfect" method but seems ok for now..
Cheers,
Ollie

[kevwilde]

Hi Ollie and Ron,

Checking back here, I have completely disassembled the gripper mech and oiled it up again. After 20 years of none-operation, the oil had solidified, making it impossible to use the motor spindle to move it to a position for me to lubricate it back alive. Disassembling, cleaning and reoiling did the trick. The gripper arm is now functional again!

Looking back now, I've still got some challenges, as the write-in circuit stopped working. After pushing letter and number, the write in circuit just starts rotating without actually activating the STOP relay. I've removed the selection assembly, cleaned the wipers and the trace PCB, cleaned the whole keypad (letters & numbers assembly) but unfortunately to no avail...

Currently a bit stuck and would not mind a little bit of advice This seems to be my last major hurdle, as from read-out until sequence end, everything is working perfectly.

Kind regards,

Kevin

[Ron Rich]

Hi Kevin,
The factory used a graphite based grease in those grippers. If someone added a non graphite grease, it tended to become glue. A graphite based grease will be softened if a 20 wt ND oil is "worked into" it. I don't know what's available in Belgium, but if you can, I suggest you re grease it with a graphite grease, and use only the above oil every year or so. This oil also should be used as the oil for the whole mech, IMHO, and do not forget the oil wick on the "front" of the gripper motor . Also, don't forget both bearings in the WI -AC- motor (avoid dis-assembly of this motor, if at all possible !).
For the WI problem-- see the FAQ's section post on "Contacts ---". Ron Rich

[kevwilde]

Sept 27, 2020 17:03:00 GMT Ron Rich said:

Hi Kevin,
The factory used a graphite based grease in those grippers. If someone added a non graphite grease, it tended to become glue. A graphite based grease will be softened if a 20 wt ND oil is "worked into" it. I don't know what's available in Belgium, but if you can, I suggest you re grease it with a graphite grease, and use only the above oil every year or so. This oil also should be used as the oil for the whole mech, IMHO, and do not forget the oil wick on the "front" of the gripper motor . Also, don't forget both bearings in the WI -AC- motor (avoid dis-assembly of this motor, if at all possible !).
For the WI problem-- see the FAQ's section post on "Contacts ---". Ron Rich

Will do, Ron.

Any suggestions for my write in issue? Basically I notice that the stop Coil is not being triggered. Pcb and wiper contacts have been cleaned.

[Ron Rich]

Hi Kevin,
Didja read our FAQ's as above-- answered there ! Ron Rich

[kevwilde]

Hi Ron,

I did but unfortunately that was not the problem.

I did however just found the solution. By backtracking to the previous sequence step (write in motor activation) i read that that also completes a connections towards the stop relay. I rebent the stop relay switch on the Write In coil switches and it worked again!

Super excited about fixing my first jukebox! Thank you very much for the great assistance!

[Ron Rich]

Hi Kevin,
Gld you "got it"-- now enjoy your music ! Ron Rich