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Messages - benzeene

#1
Hey All,

I've read with great interest, because I'm having 2nd strike issues - where the hammer is striking the tine out of phase and that "damps out" the already vibrating tine.

Is there anything that can be done to improve this?  What typically are the contributing issues? 

FYI, I am using the sustain pedal during this, and so I'm doubtful that the damper has any affect.  Does the strike line factor play into this?

All problems are on the low end - which - not accidentally - may allow more opportunity due to the out of phase strike time (more).

Let me know what you think.

Thanks,

Ben

PS:  1978 Mark 1 Stage
#2
Provided that the back rail is more or less even and the keys are not warped, adjustments to the balance rail should normalize both the key up/key down "throw distance" of the pedestal (as measured against the action rail) and the keys evenness at the same time.  The good news is that I found this to be so.  It may be that I was lucky, but conceptually it makes sense.  Primarily, my approach seems to be the right emphasis for my problem.  Please keep us all posted on your progress, as someone will be helped by this discussion.

Not sure what the "tine stopping" issue is, but - if it's what I think it is - it sounds like a shimming of the harp might be in order.
#3
OK All,

I've just successfully completed fixing my action issues with my '78 Rhodes Stage Mark 1.

Just to fill you in, I had taken most of the approaches that involved measuring and shimming the balance rail felt to achieve equal "key drop."  None of the approaches worked for my problem. 

My issue was related to different parts of the keyboard having obviously different key drops - the very top and bottom seemed to be around the optimal 3/8 inches, but the center (heavy traffic) area was far less.  When at rest the keys in the middle of the keyboard were very close to the front rail.

So, it would have seemed obvious that correcting the key drop would have sufficed.

It did not.

I decided to really look at the problem.  In my reading here, I got the impression that the back rail felt might be an issue - maybe worn etc.  Unfortunately (or fortunately it turns out) I had to remove all the hammers and damper assemblies in order to examine the back rail.  I found the back rail to be in acceptable condition, and certainly not bad enough to cause the problem.

But I did notice something that was very important:  The pedestal "throw length" (for lack of a better term), was drastically different over the various ranges of the instrument.  Since I had just removed all the hammer assemblies, I knew that the hammers were identical in all ranges, and that the physics of the key action system should also be identical - if the action was to respond and play the same in all ranges (something all us pianists strive for).

There were other problems as well:  There was a gap between the back rail and the case in the troubled ranges as well.  But I decided that all other problems were subservient to the big problem:  All pedestal throws should be identical.  If they weren't we would never achieve good playing feel across all ranges.

Taking this as the crux of the issue, I did the following:

1.  Examined the keys that were responding in the way I would expect.  In my case, this was the lowest and highest note on my 73 keyboard.

2.  With hammer and damper assemblies out of the piano, the key gravity would place the keys in the depressed key position (the weight of the hammer itself is the counter-weight).

3.  In the above mentioned depressed hammer position, I measured the location of each pedestal for each key against the action rail (on which the hammers are installed).  The action rail is the machined aluminum part of the piano, which I considered to be the one unchangeable aspect of the instrument.  It doesn't change shape with age...

4.  I replaced all the center (balance) rail felts with new ones from a piano supply house.

5.  Then, using LOTS of shims, I shimmed each key on the balance rail, until all pedestal felts (for each key) were equal across the entire instrument - when measured against the action rail.  My theory was that the distance the pedestal traveled up and down against the action rail was the most important feature of the action.  If it wasn't equal, there would not be consistency between different ranges of the instrument.

6.  I paid no attention to the felts under the key guides (front rail).  They will not come into play when the hammer assemblies are reinstalled ( for reasons gone into elsewhere).

7.  I did use a piece of wood and a hammer to tap on balance rail guide pins as needed to fix problems of unevenness right to left (some of my keys were tilted one way or the other).  Just little taps were enough.

The result of the above is a keyboard that plays properly and feels good across the entire instrument.  Incidentally, the key drop also now measures correctly (which makes sense if you think about it).

So, a couple of comments:

A.  Measuring the key drop - in and of itself - is not an appropriate fix for my specific problem.  It might work in most cases, but clearly not in all.

B.  The physics of the problem needs to be considered carefully in order to address the specific problem with your instrument.  We know that the action rail is not changing shape.  We know that the hammer assemblies are identical in the stage mark 1 circa 1978 (probably in all, but I don't know that).  So the physics of the action itself needs to be addressed in order to fix or optimize the situation.  Look at the problem from that perspective, and I think you'll side step difficulties.

C.  The key drop measurement should end up being correct by using the above strategy if the keys are not damaged.

D.  THIS THING IS A TOY!  You just can't compare the Rhodes action to a piano.  No comparison.  It's a design that works by some accident of fate.  The damper system is as crude as it gets.  The good news is that through trial and error, they pretty much got it right.  Mine plays just beautifully now.  Never thought it would.

Anyway, I hope this is valuable to someone out there.

Peace and love,

Ben Dowling
#4
Hey All,

I'm getting in a little late on this one, but have related problems:

I was initially instructed to set the "key dip" by measuring key down from key up - on the front of the key and shimming as necessary to reach the optimal 3/8 measurement of displacement.  In doing so, here was my result:

1.  In the low use area of the keyboard - very low range and highest note - the keys looked pretty normal and played well.

2.  In the mid to upper register the keys would push all the way down till they struck the wood in front of the key with the lip of the key top.  When not played, the key was lower than the low-use range by nearly a half - giving a hug dip in the key hight in the middle register.

So, clearly setting the dip without considering the rest of the problem did not suffice.

Back to square A

So I removed the keys again, and removed the hammer combs and damper assemblies entirely - so I could get a look at the problem.  In reading comments above, I thought that maybe I had a problem with the back rail felt being worn or damaged.

Turns out, not so.

Placing the keys back in, however, did result in an obvious problem:

The key pedestals were significantly different hight following the same ranges as outlined above. When the key was fully depressed - actually when resting from gravity - without the hammer to balance against, the pedestal felt was nearly a half inch lower in the middle ranges!  This, by measuring from the action rail (where the keys are mounted) to the pedestal felt.

Obviously, the key pedestals on all keys should be roughly equal, or depressing the key in the middle of the keyboard will not have the same physical affect as playing one at the very bottom.

Since all hammer assemblies - as clear as I can make out - are identical, we need to insure that the distance from the back rail and the throw of the key itself are pretty doggone close.

One other twist:

I noticed that the back rail is not flush with the case - having a upward bow in the problem middle range.  An obvious problem, but one that doesn't hold much hope of repair, I'm afraid.

So, now I'm shimming the center rail, such that the key pedestals are roughly the same distance from the action rail.  Not sure how it will come out, but thought I'd share that.  Should have a clearer idea if this helped soon.

Stay tuned...

All best,

Ben Dowling