Advice for repair/ideas, Rock-Ola 442, making some progress

[ollie]

Haha! thanks for the offer! Those Chevy Diesel Trucks are cool, We (my family) used to borrow one when moving stuff
back in the day..massive torque..I think it had the biggest availible engine..6.5L maybe? it was normally utilized/rebuilt
as a snowplowing truck in the winter..go figure.

[Ron Rich]

Hi Ollie,
The 1982 was the first year they used a 6.2 L. It does not have a lot of power, and the gearing, unless "dropped" into 4 wheel drive, is too high. I removed the "auto-lock" hubs and stuck manuals on it, so I can go into 4wd without locking up my wheels on pavement. Works great-- this is the 3rd one of these I have owned-- 1st one ran 498k miles before blowing the by-pass hose at 70+ mph-- engine seized up--. 2nd one had an auto transmission-- I did not like it--sold it at around 200k--this one was purchased new by my neighbor, and I bought it when he told me he wanted a "new smaller SUV"-- Purchased it in 1992- 138k miles on it when I got it--- like I said-- it's now 4sale, as I have gotten too old to drive it---
Ron Rich

[ollie]

Cool, good luck on the sale.

[ollie]

Hello,
Ok, Today I had another chance to work on the 442 (It´s a 30 min drive away)
Now, it appears like maybe..I´m getting somewhere here-

-first, somebody before I started looking at it has had an extra diode (like a small 1N4007) soldered on the play relay (for unknown reasons?)..
Measuring after the diode there was no voltage, but it has 30V DC before it, So...I figured what the heck, it´s not
in the original schematics, I´ll bypass it and see what I get.

Bypassed-
Now that I push the "Scan lever" it actually spins the motor, but very shortly, like 2 seconds, before it blows the fuse/fuses in the
DC section! hmmm..

I found another thread on the web that discusses the motors and that they can short out (or nearly short) sending way
too much current thru the DC section.
(I think you have to have your google account active/logged in to see the discussion here below?)

groups.google.com/g/alt.collecting.juke-boxes/c/BGJIYyNEaaM?pli=1

I can also inform you that today I have lubed the gears on the Mag-motor, And also removed it from the mechanics/wheel, so it dangles free
from the Magazine itself.. but it still blows the fuse..(motor "feels" like it spins alright, but that doesnt
mean there can not still be a short inside, naturally..
I intend to do like the guy said in other thread and try to measure with an external DC power supply, and find how many Amps it takes
to spin it at 28V or abouts..

So, my conlusion for now is: remove the extra diode and test the motor/ or, take it apart and try to service it...to
poissible make it spin more freely/clean the carbon and get rid of the "short" inside...

Question: how common is it that the old motors act up this way? Have any of you experienced it?

Many thanks for your time, Ollie

[ollie]

image of "modded" Diode already existing before I started tinkering with the phone/Jukebox.
(on Play Relay)

ibb.co/bsBL2hs

here you see the small Diode that is soldered on the Play relay.
Bypassing/bridging it brings 33V DC up to the top connectors of the relay and sends
33V DC to the motors, but like mentioned, fuse blows almost immediately, after just a few sec of motor turning.

[Ron Rich]

Hi Ollie,
Since I can't see it-- the "extra diode" -- I dono-??- look at the DC supply-- any "AC" in it ? What size/type fuse is blowing ? Yes those old motor brushes can cause it to attempt to draw too much power-- remove the armature, clean off the carbon, and take a "wooden" stick, like a tooth pick, and clean in between the splits on the copper. Replace the brushes if less then 1/4 inch long. If grease in gear box has hardened, it MUST be removed, totally, and re-placed. Don't mix new and old grease---will quickly turn to glue ! Ron Rich

[jukenorman]

Hi Ollie,
I think you should service the motor before getting bogged down in anything else, you never know what you might find - eliminate the simple things first. I have no idea why that diode would be there!
Norman.

[ollie]

Thanks guys, I will take it apart, clean and lube , then test the motor and see how much current it draws when spinning with
an external/"lab" power supply. I´ll report back when I have the results.
Cheers, Ollie

[ollie]

Hi,I took the magazine motor apart, it was obviously full of carbon and soot residue..I cleaned it out, according to
many a You tube videos and web explainantions, looks much better now, and then I lubed it up good, made the bearings / axle spin
more freely and what not.at least it doesnt feel so bad when spinning it by hand now...But

Hooked it up to a friends external DC power supply with an Amp meter..
Unfortunately, it wants upwards of 3 amps at 30V DC before it spins and even then its not spinning evenly, stops and
acts up, feels like it wants even more Amps/power...So..
There is likely some sorta short in the windings or similar?

This explains why the "Juke" blows the fuse and has only sporadically once spun the magazine (if just for a few secs, before the
fuse blew on me)

So, granted, for sake of knowing, would have been interesting if a had a healty motor to compare with but I don´t..
All I know is that it should have been spinning in the the .5 Amps range if I get this guy right in Germany. (who seems to know
his stuff!)

www.youtube.com/watch?v=S07V275Sgzg&t=606s


I´ll see what the next step will be..Maybe I´ll try to source a new/restored motor from Germany? we´ll see.

Cheers
Ollie

[Ron Rich]

Hi Ollie,
I can't understand a word that gent says ?? Did you take a tooth pick to the "slots" on the commutator, like i said above ? If so, you are looking for at least an armature rewind job --- Ron Rich

[ollie]

Whatta ya mean, you don´t speak perfect german? hehe!  ( I understand about 1/3 of what he is saying)
Sure, I did what you said, carfully with a pick.
I did not go as aggressive as the german fellow with a razor blade or whatnot..
My motor kinda runs, but it wants waaayy to much power (amps) to spin.. something´s wrong with it I reckon.

[Ron Rich]

Hi Ollie,
My German ain't what it used to be-- his accent is much different then what I have heard-- Might try the razor blade thing-- can't cause any more harm-- shorted windings, or commutator, in my opinion-- Ron Rich

[ollie]

And, Measuring ohms on the motor (removed) between ground - and + I get 3.0 Ohms

Is that normal?
does it tell me anything ?

Many Thanks, Ollie

[Ron Rich]

Hi Ollie,
I would hazard to say that you are reading the winding, of the motor-- Sorry, I have no idea what "normal" should be there, nor a motor to check that with-- Might try reading the other motor--should be very near the same --- Ron Rich

[ollie]

Yes, You are right, I will loosen the other motor (Gripper) and test/measure that one..might
tell me something...In any event, Im beginning to suspect I will need a good motor (new/functioning) before I can
get any further with the repair of this Rock-Ola..