1228 - Tonearm Adjustment

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stanleyf61
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1228 - Tonearm Adjustment

Post by stanleyf61 » 20 Apr 2018 14:50

Hi,

Working to properly adjust tonearm for auto and cue lift for manual operation. I have followed the guidance in the 1228 manual aka page 16 figure 25. Have also followed the instructions near the end of the 1218-does not spin post at https://www.vinylengine.com/turntable_f ... 1&start=30

Auto function works fine. Manual function has a slight issue. In Manual when i use the cue lever to lift the tonearm and then move the tonearm toward the record it stops or slightly catches at where the tonearm would typically stop and drop in the auto function. Basically the guide (239) on the segment (237) is bumping into the positioning slide (219) because it is not adjusted exactly correct.

Any suggestions on dialing this in?

thanks, stan
Attachments
IMG_4405.JPG
segment guide bumping into position slide at top left
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DSJR
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Re: 1228 - Tonearm Adjustment

Post by DSJR » 20 Apr 2018 15:34

I suspect the overall lifting height as set by the thumb nut on top of the cueing lift is still slightly too high (#68 in diagram 9 in the service manual). I suspect that if you drop the height a mm or so, it'll clear - my 701 is exactly the same! - and then reduce the maximum end stop (set-screw on the 'lateral' bearing pivot cradle behind the pivots and under the 'vertical bearing' arm-tube cradle - fig 10 shows it) to match, you'll have perfect working...

I think one usually sets these things with the cueing adjustment screw set slightly 'low' to start with. Set the thumb nut #68 to give minimum height in this case - fig 25, then part cycle the mech so the arm is fully lifted and set the max end stop (screw #60 just behind the tonearm pivots and under the vertical pivot and arm-tube cradle) to finish BEFORE re-setting cueing height. Other Duals are set with arm fully lifted by the mechanism but not this one...
Last edited by DSJR on 20 Apr 2018 15:39, edited 1 time in total.

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Re: 1228 - Tonearm Adjustment

Post by dualcan » 20 Apr 2018 15:37

Hi Stan,
Make sure that both the cue/size rail is absolutely flat and the segment perfectly parallel to chassis first. Check for bending or pliers marks.
Follow all the height adjustments in SM.
Also check if the seal for the pin height grub screw is broken (blue oval):
1228 adjust IFowler.JPG
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Once all is straight and aligned as described, that grub screw is used to set the pin height and therefore the catch height to segment. It should not need adjustment if all is straight...
Regards,
k

stanleyf61
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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 21 Apr 2018 19:49

Hi DSJR and Dualcan!

Thanks for all the great info!

Issues still exists? oh well...So i disassembled as needed and determined there are no bent parts, for example the segment and positioning slide. I measured the distance of top of segment to frame on both sides and it was the exact same. Place slide on flat service and could detect no bend. i checked the guide seal for the grub screw that that was not broken. the pin in the guide moves up and down as designed. Re-adjusted to the best of my abilities based on SM and additional guidance.

I actually have another 1228 that works correctly so did alot of comparisons but didnt find any issues. I did notice that the main bearing assembly seems slightly different (more on that in a min/next post, but dont think that is issue, just a design change in a later model?)

i have posted two pictures. The second is with the unit being cycled and shows the tonearm at 3mm height and the .5mm play as described. I then adjusted the cue lever by using adjust screw 48. to slightly lower than 2mm. When i retested it still has the stop/catch. The first picture shows how low i had to set 48 to get the tonearm by without catching with the cue lever raised.
Attachments
IMG_4426.JPG
tonearm lower to not catch
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IMG_4422.JPG
tonearm in cycle at 3mm
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dualcan
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Re: 1228 - Tonearm Adjustment

Post by dualcan » 21 Apr 2018 23:56

Hi Stan,
There is another area to investigate. These arm tubes are smaller and thinner to reduce weight, which is fine. One draw back is that the arm can be bent more readily. One bent which is not readily apparent, is right at the front edge of the bearing traverse (red dot):
arm check.JPG
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As you can see in my restoration series on this unit, this arm had a bent just behind the tone arm head.
You don't need to remove the arm to see if it's bent, simply insert a dowel or some other fitting cylinder (straw?) but no further than shown as the sound wires could be damaged. View from the side and see if the two line up of form a slight V. With bent arms, the alignments can drive you nuts... If necessary remove the arm tube carefully an straighten out, the same way I did this one in the restoration.
Regards,
k

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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 22 Apr 2018 03:12

Hi Dualcan,

Thanks for the info! I will be sure to check the tonearm as well as continue to fine tune the adjustments to see if i can get it working correctly. As an fyi, I just recently picked up this unit, but i think it has had this issue for a while. I did not look at the slide under a magnifying glass, but to the naked eye the tip of the slide where the glide is bumping into it seemed worn. not sure about that and will confirm.

On the other point i mentioned earlier, which i don't believe is related to the problem, but interesting just the same. The unit i am working on has a higher serial number 112499 (has the gold colored cam). I noticed that the part identified as "A" in figure 19 of the 1228 SM (part of 174 bearing bridge complete) is slightly different than the one that is on my other 1228, which has a much lower serial number (approximately 050000 and has the clear cam).

In the bottom two pics from the 112499 you can see that "A" has portion with an arm that vertically goes thru the horizontal section, the arm has a spring connected to it that connects back to the horizontally section to create tension. The arm has a downward curved to the left shape, but includes a factory shaped burr that points down to the about the six oclock position. This limits the total travel of the tip of "A" to about 2mm. in the first two pic on the other unit there is no burr on the arm and the total travel is about 6mm? was this just a change design that is compensated for elsewhere in relation to the other components? just curious :)

Thanks, Stan
Attachments
IMG_4418.JPG
bracket up 6mm
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IMG_4417.JPG
bracket down
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IMG_4413.JPG
bracket up 2mm
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IMG_4411.JPG
bracket down
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stanleyf61
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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 24 Apr 2018 03:18

Well looks like the tonearm is the issue...uggh

Not sure i am ready to tackle a disassembly. May live with the minor catch, may go for it... tbd

Will read up on it and post back later.

On a positive note, a 1/4 headphone plug works pretty good for the "is the tone arm straight test" :)

Thanks! Stan
Attachments
IMG_4449.JPG
angle of picture makes it look worse than actual is, but probably has slight bend
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mrow2
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Re: 1228 - Tonearm Adjustment

Post by mrow2 » 24 Apr 2018 06:23

Dowels of varying sizes are readily available at big box hardware supply places like Home Depot, and of course lumber stores. For any straightening work, you'd certainly want to be working with (softer) wood sticks, not metal. You can vary the depth a bit one way then the other, for leverage and fine tuning. I keep a small assortment for various things and they do come in handy.

stanleyf61
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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 24 Apr 2018 14:37

Thanks for the tip!, will be sure to pick some up! Was just using this to see if it was bent and not for straightening, but good to clarify so as not to encourage/confuse future readers :)

Stan

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Re: 1228 - Tonearm Adjustment

Post by dualcan » 24 Apr 2018 15:31

Hi,
To remove the arm, follow the service manual on page 8.
The first line in all these manuals is "..to fasten the unit in a repair jig..." . That is very good advise as it prevents any further damage, especially to the tonearm support bearing structure. I have placed a design for a DIY unit in the Dual Service thread above which is not too difficult to built. If you plan to service a few units, then it is a very handy way to go. Alternatively, for a one-time use, a cardboard ring is very easily prepared and is shown in the Servicing Motors thread, also in the Dual Service thread. Its main attribute is that the turntable can not easily slide off this support.
To straighten the bent tube, you can see how I did straightened the front end bent on the 1228 arm in the restoration pictures on my website, after disassembly with an appropriate sized Phillips screwdriver, Sears Craftsman no less... (in case of the 1219/29 sized tubes, a 12" nail sanded and polished):
DSC00001.JPG
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The Craftsman Philips #2 fits exactly into the tube. Since the tube is relatively soft (aluminium) you need a very straight and hard core (screwdriver shank in this case) because it is the alu tube that must take the straight contour of the shank.
To ease the job, use a bit of Vaseline inside the tube. In order to get a grip on the tube, the screwdriver can be clamped into an appropriate vice or some other clamping method. To ensure that the tube won't be damaged while you are forcing the shank into the dented section, wear leather gloves (or similar grip gloves) to enable a slip-free grip on the tube, covering as much contact area as both hands can, onto the tube. This will ensure that the force / stress on the tube applied, will not damage the tube further. Once the shaft is fully inserted and the tube rotyates relatively freely then, as Don suggested, use a soft piece of wood or similar to gently "pound" the outside creases/folds back into the round alu shape. Using soft material here, will avoid further scratching the anodized alu finish.
The longer the shaft is, the straighter the tube will be of course, hence the 12" nail for the 1219/29.
Regards,
k
k

stanleyf61
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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 25 Apr 2018 03:22

Hi Dulcan!

This is so fantastic! thanks so much for all the info! It is much appreciated! I guess i will have to give it a try, but have another project underway and some travel planned so may take a few weeks to get back to this one! Maybe around mid May. Will post as soon as i have made some progress!

thanks, stsan

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Re: 1228 - Tonearm Adjustment

Post by mrow2 » 26 Apr 2018 20:13

Great observation re: the Craftsman #2 Philips driver. I have two (at least) and one can be smoothed, polished & dedicated to this occasional task! Also have the long aluminum nail (used for aluminum gutter-mounting sometimes) for this.

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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 12 Jun 2018 03:32

Hi,

The month of May was a blur, but recently have been able to pick back up on a couple of projects. So after much prayer and supplication I have repaired the tonearm! but still having a couple of residual issues :) lol

The info that Dualcan provided in this post and that DSJR provided in a different post https://www.vinylengine.com/turntable_f ... 7&t=102766 was essential reading/study in making the repair! Thanks for all the great info!

Good news is that the tonearm is straight and the "catch" that was occurring described in the open of the post in which the segment guide bump has been resolved!

New issue which is probably related to the repair or could have been happening before is that on the start cycle the tone arm moves to drop point (but oh so close to the end of the start groove, see more on that in the note below) but right when the tone arm starts to drop it moves forward about another 1/8 of an inch and then finishes dropping. so the result is that the stylus lands way past the start groove. In experimenting with it some i noticed if i press upward on the 173 (main lever complete) which presses on 219 (positioning slide) it does seem to make the tonearm move forward ever so slightly... Any suggestions on why this drop is not working correctly?

btw... i located at the local big box hardware store a new IRWIN #2 phillps screwdriver (also came with a matching flathead) for $8 that fit inside the tonearm tube perfectly. At the store, it was very snug without lubrication. When i returned home i sprayed a small amount of white lithium grease on the shaft the phillips and then it fit perfectly. After pushing the shank thru several times, it still seemed to need a little tender adjusting, which i did by partially inserting the shank and applying pressure until i felt like it was really straight as possible.

Note - I did follow the instructions for adjusting the the drop index point as specified on page 8/9 of 9 of the instruction manual (fig 27.). But i really could not get it adjusted correctly. The earliest drop point i could obtain, was still slightly past the start groove. This makes me wonder if I should adjust E as specified on page 15 of 23 in the service manual (figure 24)?

Thanks, Stan
Attachments
IMG_5321.JPG
used heat shrink, but dont think in this pic i had applied the heat yet, it came out good though
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IMG_5311.JPG
somehow i snagged this and had to repair, what fun!
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IMG_5323.JPG
fishing the leads thru was loads of fun. Make sure to run the wires thru the second slot in the tonearm instead of either of the two round holes, also when re-assemblying don't forget (per the DSJR post) that one of the screws has reverse threads, enough said!
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IMG_5343.JPG
straighten tonearm
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IMG_5319.JPG
#2 Irwin philiips screwdriver with tone arm tube
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stanleyf61
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Re: 1228 - Tonearm Adjustment

Post by stanleyf61 » 12 Jun 2018 03:39

Also meant to include mrow2 for his help on this as well!

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Re: 1228 - Tonearm Adjustment

Post by DSJR » 12 Jun 2018 14:48

If the audio 'exit' cable to the amp are original, the V15 III has rarely sounded better than it does in a period Dual as long as the top of the cartridge is as near as darn it parallel with the record being played.

Can't help much on the lateral movement issue you have. The lifting assembly only works vertically, so maybe the main lever is snagging when it shouldn't? Is the infamous pimpel the right length? The one I bought for my 601 needed trimming slightly so the mounting pin/stud could 'spring' a little in and out as intended... Again, make sure there's a touch of free vertical 'play' when the tonearm is lifted by the mechanism - cycle the mech until just before the main lever lowers the arm-lift. Is there a 1mm or so free movement of the arm against it's max-height 'stopper?' Either this stopper adjustment can be done a smidge, or the thumb-nut at the top of the arm lift assembly (I'm tied and haven't got the relevant numbers to hand, sorry), can be adjusted to allow this small free-play. That *might* just be enough with luck.

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