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Losing odd pattern of notes on Fatar TP60L

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Organorak

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Losing odd pattern of notes on Fatar TP60L

PostSat Oct 23, 2021 10:43 am

My home organ has a stack of four Fatar TP60L keyboards. Each keyboard connects to a Doepfer MKE MIDI processor via two ribbon cables with 16 way MicroMatch connectors.

A couple of keyboards have recently intermittently started to lose notes, including annoyingly the bottom keyboard. Specifically, one is losing eight chromatically adjacant notes, and the other is losing four notes each of which is eight chromicatic notes from the next. I am wondering if a single faulty connection is causing eight notes to drop out due to the matrix diode system.

Can anyone kindly advise what to consider when diagnosing and fixing such a problem? I am aware that individual keys can be removed and contacts cleaned but the pattern of notes makes me think the problem lies somewhere other than under each missing key. I have pulled out and reconnected all keyboards but after a while the problem recurs. Sometimes when playing the fault disappears for a while, suggesting that a hard thwack somewhere might at least temporarily make the contact work again but that isn't a long term solution. As it takes several hours to take the organ apart to reach the MIDI cables and a few hours more to reassemble it, it would be helpful to have some idea of what to work on and what spare parts might be needed before I take it to pieces yet again. Obviously when I have done so before, the act of taking apart and reassembling makes everything work again...for a few weeks!
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GrahamH

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Re: Losing odd pattern of notes on Fatar TP60L

PostSat Oct 23, 2021 1:37 pm

A few years ago I tried to help somebody fix an almost identical problem to that which you describe and it took a while before I twigged what the problem was
He also had Fatar keyboards and Doepfer encoders but the main differences between his set-up and yours were
(a) his console was not as sturdy and rigid as I believe yours to be
(b) he frequently moved his console from one room to another
(c) his Fatar keyboards were not TP60’s but the cheaper model which tends to flex even more than the TP60.
All of these factors served to aggravate the main problem which in my opinion is a major flaw in the design of Fatar keyboards – namely, the use of Micromatch connectors. They may be OK for connections on fixed stationary PCBs – but definitely not in situations where there is any possibility of even the slightest movement.
Your statement that
the act of taking apart and reassembling makes everything work again...for a few weeks

gives the game away.
It doesn’t take much to dislodge a Micromatch plug, especially if it is upside down as in the case of the Fatar keyboards, and unfortunately you can’t *see* that all the pins aren’t making proper contact. But if I were a betting man, I’d put money on this being the source of your problem.

What to do to fix it?
If it is at all feasible, replace the Micromatch connectors with something more reliable (such as IDC connectors).
If that is not feasible (and it probably isn’t), do whatever is necessary to ensure that they can’t become even slightly dislodged.
If your Fatar keyboards are only supported at the ends by those ridiculous “chassis” that Fatar supply, get rid of the “chassis”, mount the keyboards on plywood or chipboard platforms and attach these to the key-cheeks – all of which will involve some work with a router. (If you PM me with an email address I can probably send some pictures).
And fit “fishplates” (plastic or wood will do) to anchor the flat cables to the plywood sheet so that you don’t dislodge the Micromatch plugs when you manhandle the keyboards.

Hopefully this will give you some ideas. Good luck!
Graham
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Organorak

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Re: Losing odd pattern of notes on Fatar TP60L

PostSat Oct 23, 2021 2:51 pm

Thank you Graham. Is there no alternative to 16 pin Micromatch connectors to go on the end of ribbon cable that are compatible with/connect into the sockets on the under side of the Fatar keyboards? Should I bite the bullet and replace all the ribbons with eight new sets of cables? If so, where might I get them from?

My console does not use the Fatar "chassis" as I found that spaced the keyboards too high and too far back for my comfort. Instead the four keyboards are parallel to each other (as opposed to slightly angled) and sit on the keycheeks of the manual below at each side. For additional rigidity I have inserted a set of stepped ledges around middle C that allow the keyboards to rest on them (directly - maybe I should have padded them with thin felt?). However, the ribbon cables dangle freely under the keyboards. I did wonder whether running some duct tape across the bottom of the keybed where the cables are inserted would help to stabilise them? Bear in mind too that, although running solid wooden platforms the whole width isn't possible (at least, not without redesigning the keycheeks), the bottom keyboard does sit directly on a solid wooden "desk" yet that too is missing notes occasionally.

At the other end of the ribbon, the cables are inserted into the MKE units which sit freely in the void under the keyboards but which should not move. I can't immediately think how they could be made any firmer.

Image

Of course when I have disassembled my console before (e.g. I had to repair a broken thumb piston once) I have checked every note and piston as each keyboard has gone back in. But it is tedious to turn it on a few days later having spent several hours taking it to pieces, only to find a group of missing notes.
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GrahamH

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Re: Losing odd pattern of notes on Fatar TP60L

PostSat Oct 23, 2021 5:00 pm

I'm not aware of any alternative connectors that would be compatible with the Micromatch sockets under your Fatar keyboards, but simply replacing the connecting ribbon cables and connectors with new ones might solve the problem.

When I looked into this before I found there were two types of Micromatch plug - one had quite short pins and one had longer curved pins. I think the latter may be more reliable.
I bought the plugs and attached them to the ribbon cables myself, but this was a bit of a nightmare because the plugs are so small and flimsy, and I broke more than one (they are not inexpensive). So I would strongly recommend getting ready made-up cables with plugs attached.

rs-online is probably the best place to start your search.
https://uk.rs-online.com/web/c/?searchTerm=micromatch

Mouser also do some Micromatch stuff.
https://www.mouser.co.uk/c/?q=micromatch

As an alternative to Duct Tape you might consider using Blu Tack.

A more radical solution (or a last resort!) would be to hack into the Fatar PCBs and somehow replace the Micromatch sockets with regular IDC box headers. I did that on some Viscount keyboards a couple of years ago, but whilst you could do it with the keyboards, I don't think you could do it with the Doepfer encoders, so you'd need to replace those with (say) Midiboutique encoders. And you'd need to be pretty certain that the connectors really were the problem before applying that remedy!
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Organorak

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Re: Losing odd pattern of notes on Fatar TP60L

PostSun Oct 24, 2021 3:50 am

Thank you Graham.

Doing the crimping myself isn't an option - aside from my lack of experience, the Micromatch crimping pliers cost around £1500! But the terminals are sold without cable. Do you know where (in the UK) I might be able to get new cables made up? Doepfer supply them but buying from Germany has become very complicated recently.

Many Hauptwrkians use Fatar keyboards, e.g. as supplied by Midiworks. How is this issue of missing groups of four or eight notes not a more common problem?
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GrahamH

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Re: Losing odd pattern of notes on Fatar TP60L

PostSun Oct 24, 2021 4:38 am

David

As for why the problem is not more widespread - one possible reason might be that the cables provided by Doepfer to hook up Fatar keyboards with their encoders do not have the same Micromatch plugs/terminations as those provided by Midiboutique for hooking up to their encoders. The only time I encountered the problem was with Doepfer encoders.
So far, five years on and since anchoring down the cables, I haven't encountered the same issues with two four-manual installations where I used Midiboutique kit. I don't know what Midiworks Canada use.
Midiboutique's plugs have "claws" whereas the Doepfer version have very short pins and for that reason I wouldn't recommend going to Doepfer. Unfortunately for you, Midiboutique's cables only have Micromatch connectors at the keyboard end. Their encoders very sensibly have 16 way box headers for regular IDC connectors.
The two links that I gave in my last post offer ready made-up cables but navigating their websites to find exactly what you want may require perseverance!

Graham
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Organorak

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Re: Losing odd pattern of notes on Fatar TP60L

PostSun Oct 24, 2021 9:15 am

Thanks Graham.

I'm confused - if Midiboutique ribbon cables use a different, more reliable kind of plug, how do they connect to the Fatar keyboards? I can appreciate a ribbon cable could have a different connector type at each end, but if the problem is the "male" Micromatch connector that goes into the base of the Fatar keyboards, is there any other type of connector that is compatible with whatever is on the Fatars? If so I could look at having made up a ribbon cable with that at one end and a Micromatch at the MKE end. You mentoned there are two types of Micromatch plus with short or curved pins but I'm none the wiser whether a cable with the longer curved pins could connect either to the keyboards or to the MKE.

Failing that, do you have any suggestions for anchoring Micromatch plugs into the base of Fatar TP60 keyboards securely enough to stop any movement when playing, but not irreversibly so (since obviously if notes on a lower keyboard fail again, everything has to come out again....) Where would you suggest putting the Blutack or Duct tape to minimise any movement of the ribbon cables once plugged into the base of the Fatars?

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