This symptom brings to mind a Tron Tech Hint I don't have out there.
Possibility that your keys are hitting the crossbars. If you quickly
press a key and hear a "clink" before any sound from the tape (if any
tape sound at all), this could be it.
Remove the keyboard and turn it over. There are two bars that run
across the pad arms on most keyboards, and on (most?) M400 machines it
floats (can bend easily). I've heard that Streetly removes this thing
entirely, and that's an option. I leave it there and bend it up or
down (toward or away from the keyboard) to allow for full key travel
to contact the tape without "clinkage".
If this is not it, you could have key adjustment problems, or you
could have a headblock wiring problem.
My guess:
1) Those stupid bars. If you mess with those bars and get full travel
again, readjust your keys from scratch. Under NO circumstances should
the screws for keyboard adjustment be 'really cranked', as that
indicates improper adjustment (you have to learn how to do it), or
another problem (like a Sound Sales Bodge causing frame sag (must be
fixed)).
2) Screwed up keyboard adjustment. First make sure the machine
doesn't have frame sag or something else that may hinder key
adjustment. Fix that first. Then it does sound like your key
adjustment needs to be revisited, so back off what you've done, and
start over. My site has "my" keyboard adjustment tips, but you do
need to make sure you don't have frame sag or some other problem.
3) Something worse, like headblock wiring or a bad head(s). You could
also have erased tapes if your head was magnetized. You may need to
seek professional help.
DO NOT unplug the headblock and plug it back in without shorting the
preamp and/or demagging the heads. Again, see my site.
Good luck...
...kl...
On Thu, Jan 6, 2011 at 6:34 AM, adaviesmaitland
<
adaviesmaitland@...> wrote:
> Hello to all.
>
> I'm new to the forum and have a question about an issue I'm having with my M400.
>
> Unfortunately, #1122 has been neglected over the last 12 months and when I fired him up the other day I discovered that there was no output at all from the B below middle C and the F above middle C. I adjusted the pressure pad but was unable to get any sound until the screw was down to it's fullest extent ie all the way down. In the case of the F there was no sound at all, even after this was done. Some of the pinch rollers move more freely than others but the pinch rollers associated with these keys are OK.
>
> Can anyone tell whether I have a warped key or something else altogether and how can I put it to rights?
>
> Cheers,
>
> Andrew
> Mellotronist of the Antipodes
>
>
>
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