Significantly misaligned keybed and action assembly - how would you fix it?

[jdromano2]

Hi folks, excited to be part of the community. After many years as a strictly acoustic pianist I was recently gifted a '76 Rhodes Stage, and it was a prime contender for being refreshed/refurbished.

This model was from the period where the felts were glued to the hammer cams rather than the key pedestals, so I removed the felts, cleaned the hammer cams fully, and installed the Miracle Mod and new felts onto the key pedestals. When reassembling, I noticed that the key pedestals and the hammer cams are significantly misaligned horizontally (pics below). This misalignment occurs across the entire length of the keyboard but is most severe on the bass end. It's bad enough that some keys hit both their own hammer and the one to the left, but this wasn't a problem before I installed the mod. Maybe something about the felts on the hammer cams rather than the key pedestals granted just enough clearance that they didn't contact eachother - whatever it is, I can't be sure.

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Now I need to figure out how to make it so the keys don't contact multiple hammer cams, but info for people with similar issues is a bit unsatisfying:

- Some folks suggest putting a shim on one side or the other to push the whole action rail left or right, but I don't see how this is possible since the action assembly screws right into existing holes on the keybed.
- I'd try shifting the hammers themselves left or right, but they seem to be in perfect alignment with the tone bars and dampers already, so I'm reluctant to screw that up.
- Given its age, the hammers seem brittle enough that I don't want to mess with heating/bending/reshaping them in any way.

What would you do? My thoughts are to plane down the sides of the key pedestals that are contacting the adjacent hammers, leaving the ones that don't contact alone. Would love to hear folks' thoughts and if they have experience with this or similar issues.

[sean]

Don't modify the keys, pedestals, nor hammers.

You need to sit in the corner and think about what you did.  No TV for a week.

I fear that you might have gotten the keybed out-of-square.  It shouldn't flex, but it can... it is old.
(I am old, but I cannot flex.)  So check the keybed to see if one of the mounting screws pulled it out of square, or if one of the mounting screws is bent, or if the keybed is not sitting flat.

You must swear that you have never dropped the piano on one end, nor ever stored it in the closet on one end.

Anyway, you must figure out what changed a tiny bit when you did the recent maintenance.

In the 1976 Mark 1, you might still have a wooden action rail. But I really don't think you do, I think when they switched to all-plastic hammers in 1974, they also switched the action rail to extruded aluminum, and the harp supports are aluminum as well.

So if you have a metal action rail, then your hammer flanges are mounted in groups-of-twelve (as a "hammer comb").  These are screwed into the action rail, and they might slightly move a tiny bit if you loosened it up, and shoved it and held it to the left while you tighten it up. You can move them octave-by-octave.  I think this is the most-likely fix.

Also, the metal harp supports are mounted to the keybed with slotted holes in the harp support.  Unscrew the four nuts, then you can slide the whole harp (and action rail) to the left.  But this does not allow you to adjust the left side without moving the right side.  It should only take a few hours of fiddling until you find the sweet spot.

You should also verify that the action rail is still tightly attached to the harp supports.
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If you still have a wooden action rail, then the hammer flanges are individually screwed down to the action rail.  I don't recommend unscrewing the hammer flanges.  They break very easily.  Adjustments are hard, and only small changes are easily made.  Usually the screws that hold the action rail to the keybed are pretty hard to get wrong - but you might get lucky by loosening the screws and nudging the action rail to the left.

There is also the chance that you put a huge shim on top of one harp support (or removed one), but I think you would have mentioned that.

I can't think of any other possibilities.

Sean

[jdromano2]

Yikes. Nope - I take good care of my equipment. It was kept carefully in a climate controlled basement for the last ~20 years, gifted to me, driven in a car lying flat, and has been in my 45% humidity climate controlled basement since. No bumps or bruises, or being stored on its end.

It indeed has an aluminum action and aluminum vertical harp supports. I've found that the screws that hold the action rail to the keybed have some play if loosened, so I did roughly what you suggested - shifted the action rail supports slightly to the left, fixed the action rail to the harp supports using the bolts, and then tightened down the action rail to the keybed.

In other words, order of reassembly mattered - I had to align the action rail to the key pedestals using the harp support attachments first, then tighten the screws from the action rail to the keybed. This fixed it and everything feels solid and is measuring square.

FWIW: I considered trying to shift the hammer combs like you suggested, but am too nervous to tweak the brittle plastic given its age. Anything like that I would probably leave to an expert