Rockola 442 Skips tracks with new cart

Hi Folks, just got hold of a Rockola 442. It has a new shure M44-7 cartridge fitted, but I notice it often skips on a lot of songs. Sometimes the start, sometimes the middle repeatedly.

The tone arm seems to move freely, but when I checked the tracking weight it's showing 4g+. According to the specs from Shure this cart should track from 1.5-3G .i also notice that it sounded as if the body of the cart was catching on some records.

So, I checked out the service data and made some adjustments to the spring. I got it under 3G , and sure enough the records played fine, but at the end of the record the arm would skip around like an old gramophone without returning. The spring has also made some pinging noises when moving the arm up and down. Is there any advice on this generally? Should the spring contact points be greased for example?

I've increased the tracking weight gradually, and may have found the sweet spot, so far records haven't jumped and the arm returns. I guess when it's too light the mechanism doesn't work correctly? The stylus does look slightly bent so I may order another as a precaution

I sense I will have to mess about with this machine a fair bit to get it up to scratch, but I'm enjoying getting to know it. Strangely I've noticed that after selecting one track, sometimes a random other song gets played!

Any advice would be cool, I've waited to get this for so long and it's a lovely machine

Thanks
Adam

Hi Adam,
Two things come directly to mind on this type of problem--
1. Lack of proper lubrication, on both the tone arm "shaft" and "pivots".
2. "Stiff" tonearm wire--which acts like a spring, biasing the tone arm in one direction, or the other.
I have also seen such things as the cartridge being incorrectly installed, bad needles (you mentioned it's "bent"), "height adjustment screw" (binding), and other "obstructions" to the tone arm, moving across the records.
NO grease !!!
As for the bouncing around, at record's end--could someone have added to much tension, to the end of record switch ??
As for the "extra selections", you will need to trouble shoot this, and at least pin it down to which section is causing it--write-in or read-out. See the Service Manual---
Ron Rich

The issue of these junky-juke tonearms comes up so often I should make the response a cut 'n paste.

Adam, the problem is that the arm has both crude bearings and is unbalanced.

All the weight of the arm is "falling" forward of the fulcrum point.

Here is how I deal with this problem:

1) Pull back or cut away any cloth wrap on the tonearm cable. Only the area between the arm and the strain relief need be cleared.

2) Set the trip switch contacts as close together as possible to keep them from loading the arm during the play grooves.

3 Drill a hole in the rear of the arm and add a counterweight. This is the single most important step and once all are done the arm will track perfectly at 2g with no stylus wobble.

The counterweight can be an actual one made for a tonearm or just a series of washers between two bolts.

Here is an AMI-I 200's arm:

http://s1192.photobucket.com/user/Rob-N ... ort=3&o=62 This arm was much worse than your R-O. With a counterweight and new pickup wires (probably not needed in your case) it too tracks correctly at 2g.

Throw away that crappy spring that rock-ola used to set tracking.

That later R-O arm could have been one of the best in that industry. It is low mass and the horizontal bearing, while simple, is still decent when proper balance is used.

Rob/NYC

Well, I swapped the shure m44-7 for a Stanton 505 I had lying around from my dj deck. It's tracking at around 3-4g quite happily and performs just fine as
It was designed to track up to 5g. I've got a new stylus on order so will consider the tone arm sorted for the time being.

I hear what you're saying about the counterweight, and I would like it to track lighter so I will plan this for the future. Right now I just want to enjoy my juke

I have two other issues now:

1) around 30-40% of the time the gripper either doesn't pick up a record correctly or doesn't set it on the deck correctly. Judging from previous posts it sounds like oil is my issue, I'll buy some today.

2) initially this didn't happen, but after having it switched on some hours when I made a selection the write in motor didn't do anything and the buttons remained depressed. I found if I keep my finger on the number the write in motor will go round and make the selection, but it seemed to take longer than before. Once selected both buttons would pop back out again

3) sometimes when a track has finished and the amp is off, I get some loud popping from the speakers, almost like a gun going off - this hasnt occurred much yet thankfully. It sounds almost like it could be the switch that cuts the amp arc-ing, but I also need to clean the volume pot so could be that too I guess

Thanks so far for the help, I have some family coming round to play with it this weekend so would be nice to have it in a "usable" state

Adam, the gripper bow problem is lubrication and grease that has become sludge. With the gripper just closing to lift a record off the T-T pull outward on the bow as if to open it again and let it go. If there is any sluggishness that will confirm the diagnosis.

Stop the mech with gripper vertical (no record) then carefully run some light oil down the side of the lower cam and into the cam box. Work the gripper up and down to hasten the penetration of the oil.

With the gripper bow open over the magazine add light oil to the other and of the cam box.

Hopefully this will solve the problem by loosening the old oil. After a period of usage add some 20wt oil.

if the above is not totally effective use some heat from a hair dryer (remove records) and get the cam box just a bit too hot to hold, then add oil as above.

I doubt you'll have to go beyond this point. however there are cases where it is necessary to remove-disassemble the entire gripper and cam and soak it in solvent. I've used diluted floor stripper. This is a mess and I do hope it will not be needed.

The keyboard issue may just be the treadle switches that start the search operation when both buttons are pressed. Look for leaf switches that close as buttons are pressed.

The amp noises may be cause for concern. These amps are not actually off as long as the machine is turned on -only muted. The noise you are hearing is likely originating in the power output stage (audio) or the power supply itself. Either-way it is best to not use the machine until the amp has been rebuilt. It is some 46 years old. If you really want to use it in the mean time. keep an eye on the temperature of the final's heatsinks. These should not be anything more than slightly warm when the amp is not playing. If they are hot, it means that either the bias is being disturbed by leakage in a previous stage or, the output transistors themselves have developed leakage. This is common on aged germanium semiconductors.

DO check the fuses for proper ratings.

Another area to check are the rubber motor mounts for the T-T motor and check that the puck has not hardened too much. These steps will reduce rumble.

Good luck.

Rob/NYC

Thanks Rob. Is the rebuild largely to replace electrolytic capacitors? I was considering buying another amp and rebuilding it then swapping, or maybe swapping it in and rebuilding the current one.

I'll obtain the circuit diagrams and start having a look. This morning the selection buttons would do nothing, even with the number held down. Then after playing around, scanning then putting back into operation mode they started working. I see these leaf switches, do they maybe need cleaning?

Adam, essentially ALL contacts on that machine can do with a cleaning and possibly de-pitting.

But be careful not to band and deform them in the process.

These mechanical memory machines have to lock out the keyboard while searching, then punching the pin. From what you are describing I suspect that the relays involved in writing-in the selection are also making poor contacts and not allowing the keyboard to become active after a write-in function.

Servicing relay and leaf contacts is not hard. It comes down to common sense. A contact should have enough overtravel to have a slight 'wiping" action. But be careful to make sure that where there are three blades and the center one switches from one to the other that the center breaks before it makes contact with the alternate. A small contact file and blade bender are the tools used -sparingly-. Often just a cleaning with a piece of rough card stock (cheap business card) with alcohol or contact cleaner will be enough.

A manual is a good idea, especially if this is your first R-O of this era.

They are available from Always jukin or Victory Glass.

As for the amp, "most" of the problems will be the capacitors. A manual will have the schematics and so does this site: http://www.verntisdale.com/Rockolaschem.htm

Rob

Guy's
I tend to dis-agree here--IMHO, a "contact file" is only to be used as a "last resort" ! A contact burnishing tool, does a much nicer job of "dressing" contacts, if used properly. A file must be used if the contact is visibly "pitted", which, once again, IMHO, should always be followed by the burnishing tool.
I also disagree in the use of "light oil". I find that, yes, it WILL take longer to work 20 wt. oil into the gripper, however it will also last longer ! Some "light oil" will not "combine" with the graphite grease the factory used--it seams to cause it to become "even more sticky"--- Ron Rich

Well, I've oiled the gripper mechanism but it did seem to move freely before. I've only used regular 3 in 1 as it's very hard to find the motor stuff in the UK (I'm ordering some in!).

It still doesn't pick records up correctly - Any further tips? I have only managed to half fill the basket so far, it does seem to rotate slightly slower half way round because of this, I wondered if that could be it. I'm stocking it up fully tonight and will see if that makes any difference

I'm going to focus on the gripper issues first I think

I have found that using "regular" ("Multi-purpose/Household") 3 in One is a "NO-NO"--it does not "combine" with the graphite grease, and causes even more problems--I would clean it all out, then wait for the proper oil !
Ron Rich

It still doesn't pick records up correctly - Any further tips? I have only managed to half fill the basket so far, it does seem to rotate slightly slower half way round because of this

These machines use dynamic braking. This involves disconnecting the basket motor when a stop is indicated and instantly placing a shunt across the armature to make it stop without coasting. This works well enough but a serious imbalance and/or some backlash in the gears will allow some wiggle room (tech term) and throw off the centering.

Finding this out belatedly is why in-person trouble shooting is so much more efficient.

Rob

Well, I filled the basket completely last night, and it rotates much better and of all the tracks I played, only ONE record was incorrectly placed on the deck, all were at least picked up, so that issue may be resolved now - newb error perhaps. I did have to manually select any tracks ending in 8, and it was temperamental on so other lower selections to the right of the title board, I'm sure I've heard if this before so will check some stickies.

This is my first jukebox and I'm enjoying getting to know the machine, it's a privilege to also have access to such specialist knowledge from you fellas on this board so thanks!

I checked the fuses Rob, and sure enough several are too high - 1/4 amp has a 2 amp! 1.5 has a 3.....I'm going to buy some replacements today, makes me wonder if any are there to "hide" problems, guess I'll find out if the lower ones blow! I suspect some values may not exist now, so I may need to use 300mA instead of 0.25A for example, an improvement all the same.

Ron, I hear you, I didn't use much in fact as I found the gripper to move freely anyway. I'll cease using it till the real stuff arrives. I don't know why it's so hard to find in the uk!!

Hi
Do the buttons lock in when you make selections ending in 8 and does the write in process start, if so maybe clean the slip rings on the wobble plate, regarding tone arm skipping, the tone arm assembly at the base of the tone arm and above the keeper spring may be bent slightly leading to friction which could cause this problem seen it happen before on Rockolas
Clones

Yes the buttons lock in on the 8s, in fact now most of the time they work - I've been cleaning the rings and pins with switch cleaner. I still find some selections require the number to be held down for the write in motor to start , at least for a time. I also found the write in motor would occasionally start and go round the selection wheel infinitely, or at least a minute or two. Fingers crossed, this has stopped since the cleaning!

The needle no longer skips since I used the Stanton 505 and heavier tracking weight. Occasionally some tracks the needle skips in slightly when it sets down, which I believe May be the height / clearance from the gripper arm could be too high, I'm not too fussed with it for now.

While the records are picked up much better now, I still find sometimes the gripper misaligns with the basket and misses the record. This seems to occur if the basket has to do a complete rotation, and when this happens I think I can see the basket slow a little during rotation, not a lot but perhaps enough to put the basket "out of whack" with the gripper? Is there any section in particular I might need to oil to improve this? The guy that sold me the juke has obviously oiled it, but there is potentially years of "gunk" in various places

Hi
If you have to hold in the buttons for some selections it would suggest that the contact points on the keyboard may need to be cleaned. There is an adjustment screw on the read out carriage , but i would say that this would need adjusting only if most records are not being gripped properly its detailed in the manual. Sometimes you can bend slightly the record slot so that the gripper arm will pick it up properly if its only happening on a few records.The basket moves in unison with the read out arm so it wouldn't matter if it slows down or not, the carriage motor slowing down would suggest that the motor would need cleaning or replacement. When the record basket stops is the gripper arm out of line completely with the record slot or only slightly
clones