Rowe 1100 Mech Adjustment Help..

Hey guys -
I do need help with one adjustment in my mech. Not sure which gear or cam is out of whack.

Note the image:

This is a shot of the end of the tone-arm cam, with the black spring-held lifter resting on top, like it should.

The problem is this - when the transfer arm is down, the tone-arm cam is not rotating enough, so that the black lift-arm isn't being lifted enough. What happens is that on thicker (the more brittle) records, this is no problem. But on thinner newer records, by the time the tone-arm gets to the inner grooves, it starts to float over the record - not enough weight to keep it in the grooves.

Now, if I adjust the tone-arm cam counter-clockwise, even a smidge, the tone-arm then moves over the record TOO SOON, and ends up catching the transfer arm ON it. (This, of course, is VERY problematic..!)

So seeing as how I cannot adjust the tone-arm cam any more, what else should I be looking at? As per the manual, all adjustments in the manual (as far as ones relating to tone arm and transfer motor/arm/cam) are in line.

Thanks!
-Mike

Mike, this is one of those 'tricky-finesse-y" adjustments.

You only need the slightest clearance between stylus and gripper bow:
http://s1192.photobucket.com/user/Rob-N ... rt=2&o=109

http://s1192.photobucket.com/user/Rob-N ... rt=2&o=108

Check to see if some Gepetto has bent the crescent-shaped flange that lifts the arm at an angle. That is usually what causes this problem. You may have to bend it again slightly to establish a compromise position. There are several somewhat crude fine touches necessary on these mechs. Another is to boot the cam with pvc tubing to make it lift the lever higher. This is usually done when the lift lever has worn a notch in the cam profile. I don't see that in you pic so it should be a matter of fine adjustments and slight bending.

I always took the mech through it's paces manually (no power) so as to avoid and strains and jams. from my, or other's wrong settings.

The good news is that once done you won't have to revisit these adjustments unless you replace the cart.

Rob

Mike,
Prior to "adjusting"anything, look at your needle. I have found some aftermarket needle shanks collapse, needles "twist", thus causing all types of failures. I would replace it if at all questionable, before attempting to compensate for any problem that "just started". Ron Rich

Hi, Mike, Ron is right, if this problem has just started, and you have not been doing any adjustments prior to this problem you are having, then check the stylus first, before you work your way down the tone arm, after the stylus check the screw which is situated halfway down the tone arm while a record is in play there must be a small gap between the bottom of the screw and the plate below this screw adjusts the stylus height. also check the tone arm counterweight they have been known to unscrew themselves over time. also do check the crescent shaped plate to see if it is contact with the long arm which rests on the cam while a record is in play, if it is then bend the crescent shaped plate down but only an very tiny bit or more problems will arise.

Hi Guys -
Sorry for the late reply.

Some more notes -

1. This is a new issue - I believe(*) - since rebuilding the mech and aligning everything per the manual. (* - I'm not 100% sure, since before this period, I had only one or two records in the mech to test on. Now there's more records with different thicknesses.)
2. Also, it seems to vary - on the same record, sometimes the needle will grip - not float - all the way to the end. If I were to guess, the transfer motor is moving (spin-down?) slightly more at times when cutting off, and when it does, it's giving enough lift to the arm that the needle's not having any issues.
3. The needle in there is brand new, used for only a few records now. (I had a new one, and replaced the old one when I reassembled everything.) It's POSSIBLE that this needle is more 'compact' than the old one. (The old one was very, very old.. Had to be from the mid-80's, from the style of the plastic housing on it.)
4. I don't think the needle is any culprit, however, as when this happens, the tone-arm is being held up enough to where it's not falling against the 'no-record' cancel plate. (Screw in the tonearm, without a record the tonearm drops too much and this screw rests on a metal plate, making electrical contact to cancel the record.)
5. *I* adjusted the tone-arm lift rod (the item Rob-NYC mentions) to follow procedure on the needle clearing the transfer arm. (The exact adjustment in Rob-NYC's scan.) I am going to revisit this tonight, and verify that I didn't over-adjust it, lifting the tone-arm up too much.

Thanks again guys. This has been fun.

Didja oil the gripper/transfer motor ?? When "dry" they tend to stop at "different places" ! It is possible that the cut-off (switch) for that motor has been "re-adjusted"by someone----??
How's the tonearm wire itself ? If "stiff"it will act as a spring, and cause all sorta problems--- Ron Rich

Hi, what make of cartridge do you have in it. because you will need to adjust the stylus height to suit. if it is a Stanton or something similar, they have shallower body than the original shure. also like Ron said check all wires in tone arm area, ie to read switch etc to make sure none are inhibiting the operation of the tone arm. try playing a record you know the tone floats across, and while in play lift the long arm off the cam if the record plays fine then the crescent plate may have been bent slightly. I have had 1100 mechs play records fine till half way through then start to skip or float due the plate being slightly twisted. due to someone mishandling the mech. also check the transfer motor linkage for wear in the plastic bush. where it attaches to the sector gear.

Folks, it doesn't matter what cart is used, the adjustment is based on the stylus clearing the bow.

The gripper motor is AC so it uses a rotor that has to snap back from engaging the gear and this must happen the instant power is cut to it. If these motors have been run for long periods without oil, or the wrong kind of oil, rotor retraction can become sluggish and cause coasting.

If the stylus is further away from the record at center, it means that the crescent shaped tailpiece has been incorrectly bent. Ideally it should be totally flat. At no point should it touch the lever during play mode.

This isn't a matter of tracking weight, the arm must be fully released by the lever and free is all directions. The post bearing should be flushed and then lubed with 20wt oil. Properly set up that arm will track at 1 gm -though I run them at 2gm.

This particular area is one of the "not so great" designs in an otherwise good mech. When I first saw it and the adjustment procedure, it struck me as "riggy".

Rob

Sorry Rob but I beg to differ on the cart, if the stylus height adjustment screw is set for something like an m44, and you replace it with a cart with a shallower body, then the adjustment screw could be just resting on the plate preventing the tone arm tracking properly.

Good morning.

As i said in the first sentence;

it doesn't matter what cart is used, the adjustment is based on the stylus clearing the bow.

That means that whatever cart you install, the space between the stylus and gripper must be -adjusted- to be the same....which BTW need only be a 1/16th " and yes, the limit screw needs to be adjusted as part of the package. That is really obvious with the mech in front of you.

FWIW: I've used the following carts in this 1100-1200 series: Stanton 500AL, D150, 680EE (not advised due to no anti-skate) DAT2 and Shure M75. For home use the Shure M44 with a variety of styli is more than adequate.

BTW: If the two "no record reject" wires are on the limit screw assembly, I remove them entirely and cut them at the other end. They only add drag

Rob

Good morning Rob, Yes it is obvious to you and me, but maybe not to people reading these posts for ideas. I use the shure M44 7 in my own jukes,

I am with Rob on this regarding it is down to an adjustment you need to set the long arm correctly, this is effected by the lift arm and the cresent tailpiece he mentions. The only other issue that could be effecting the adjustments is the long pin on the Crank & Pin Assembly, If the pin is loose on its rivet then this effects the drive of the Transfer Link and the Segment Gear and Shaft Assembly and ultimately the Tone arm Cam and Gripper Bow.

Check for worn parts and then re do all of the adjustments again.

Regards
Alan

Alan Hood
ami-man
UK

I also agree with Rob, and also with you Alan, it is all down to adjustment, and like you said Alan, checking the pins on the sector gear link, I have come across a few wobbly one's in the past. I did mention in earlier posts about the crescent plate, and the plastic bush in the sector drive link. I apologise for stating the obvious in the tone arm stylus height screw.

It's interesting seeing ya'll go back and forth on this.

Let me re-iterate -
WITH the cartridge AND needle that is in there now, I did the stylus-clearing-the-transfer arm adjustment. And it DID need adjustment, I bent the arm up ever so slightly. (Remember my cart was loose, I posted in my resto thread. Once I glued it back into it's .. er.. housing, it was a little low, and the needle was scraping the bow. My adjustment was perhaps.. 1/16th of an inch.)

I do not think that crescent is bent - however, I will have to check that tonight. I think Rob got close -

Rob-NYC wrote:The gripper motor is AC so it uses a rotor that has to snap back from engaging the gear and this must happen the instant power is cut to it. If these motors have been run for long periods without oil, or the wrong kind of oil, rotor retraction can become sluggish and cause coasting.

In my case, however, when the rotor releases QUICKLY (as Rob says it should) then the cam arm isn't raised enough, and the issue occurs. When the rotor 'hangs in there' a little longer, then the arm is raised enough where the problem does not present itself.

I did notice something last night, while looking at it, and this may be the cause. However, I'm not sure how to address it -
When the record is PLACED DOWN, the transfer motor stops as it should. (Rotor snapping out right away, or not.)
However, when the record is canceled, the transfer arm assembly (tone-arm cam, the gears and half-gear from the transfer motor) continue in the forward motion some, before reversing direction to raise the tone-arm and allow the arm to clamp on the record. (I will get a video of it tonight, in case my words aren't descriptive enough.)

It's as if the transfer cam is hitting the motor cutoff switch before the cycle is completely finished - and when the motor resumes, it's finishing the motion and then starting the pick-up motion. Exactly as if the transfer switch cam needs to be adjusted.

And funny enough, there's a page in my manual about adjusting the switch cam:

However, I CANNOT PERFORM THAT ADJUSTMENT. My switch cam has a notch in it, that mates up with a roll-pin that is through the drive-shaft that the cam mounts in - so I cannot rotate the cam to adjust it at all. (And, nevermind that it's calling cam switch 5 "8" - apparently this page was pulled from an earlier model and never updated. D'oh.)

Two thoughts come to mind here---
1. Check that cam switch,with an Analog meter, as shown in a post above--it may be having problems !
2. It should be adjustable as to where - when it triggers, by loosening the mounting screws and sliding it closer/further from the cam.
Ron Rich