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Pedal board MIDI connector help

PostPosted: Sun Aug 09, 2020 6:52 am
by srw647
https://photos.google.com/share/AF1QipP ... 9lMDdQYlBn

I hope that link goes to a photo of the circuit board screwed to the underneath of my pedal board - it's a DIY job that I bought from someone else. Yes, that is a matchstick holding one of the ribbons on.

As far as I can tell, the two larger ribbons on the left are taking a feed, one wire from each pedal note. The small one with the matchstick is the connection into the guts of the organ, and there's a separate single wire also connected to the guts of the organ.

The connections are beginning to fail - current state of play is that all the notes below bass A flat are returning not only their own note but also additional notes one and two minor sixths above them. The problem appears to be with the connector with the matchstick, as that's the first place (I think) that individual pedal notes are joined together.

I presume that the solution is relatively simple - I need to make clean connections for each wire in the ribbon. But to do that I also presume I need the plastic widget which clips onto the sides of the ribbon holder and creates the pressure - and that bit's gone missing, hence the matchstick.

Am I right in my presumptions? If so, is the plastic widget available separately?

(You may be able to tell that I know almost nothing about electronics. I'd like to get a fix, but I don't want to invest too much time and money, as I've got a professionally built console arriving at the end of the year, so this one will be looking for a new home.)

(And if someone can help with embedding an image in a post I'd also appreciate it!)

Re: Pedal board MIDI connector help

PostPosted: Sun Aug 09, 2020 10:20 am
by NickNelson
srw647 wrote:I presume that the solution is relatively simple - I need to make clean connections for each wire in the ribbon. But to do that I also presume I need the plastic widget which clips onto the sides of the ribbon holder and creates the pressure - and that bit's gone missing, hence the matchstick.

Am I right in my presumptions? If so, is the plastic widget available separately?


That's a 10-way two row IDC transition connector. And given the state of it I'd be inclined to agree that that's the cause of the trouble (though there might be other possibilities). I'm also inclined to think it's made by Harting. These should be readily available just about anywhere in the world (we don't know your location), but so far as I know the missing part won't be available separately.

Ideally, you would unsolder the connector from the PCB and replace it with a new one, but I'm guessing you wouldn't want to get into that.

In an emergency, I would attempt the following:

1. Obtain a replacement Transition connector of the same type and take it apart retaining the 'widget'
2. Remove the matchstick and carefully ease the ribbon cable out of the connector.
3. Cut away sufficient from the end of the cable (with a pair of scissors) to leave a clean square undamaged end.
4. Lay the cable back in the connecter (being careful to keep the red wire at the same end).
5. Clip the widget back into the connector.
6. Squeeze the assembly back together.

The last part will probably be the most difficult as it will require quite a lot of pressure. Don't expect to be able to do it
just by finger pressure. A G-clamp or possibly a pair of 'Mole' grips would do the job. It might also help to temporarily
soften the insulation of the cable by warming it first.

Nick

Re: Pedal board MIDI connector help

PostPosted: Sun Aug 09, 2020 10:31 am
by srw647
Thank you!

I'm in the UK, and you're right I wouldn't want to get into soldering if I can help it. Here's what I've found: https://uk.rs-online.com/web/p/idc-connectors/6935343/

I'll give it a go.

Re: Pedal board MIDI connector help

PostPosted: Sun Aug 09, 2020 11:29 am
by NickNelson
Actually, I think this more like what you want (unless I'm misinterpreting the photo)

https://uk.rs-online.com/web/p/idc-connectors/6935185/

Unfortunately, while all the different manufacturers' offerings work on broadly similar principles, there are differences
between the manufacturers in the exact designs. It's even possible that the ones on your board are no longer available.

Nevertheless, if you get something that looks as similar as possible it can probably be adapted/modified to work.

I have an account with RS if it helps.

Nick

Re: Pedal board MIDI connector help

PostPosted: Sun Aug 09, 2020 12:51 pm
by srw647
Thanks. I didn't find that one with my first order, so I've added a second order!

I'm going on the principle of ordering several and hoping one will do the job.

Re: Pedal board MIDI connector help

PostPosted: Sun Aug 09, 2020 3:23 pm
by engrssc
If you want to replace the connector you would need to de-solder (remove) the existing connector on the PCB (printed circuit board)

The new connector (also referred to as a header) that Nick mentioned needs to be soldered on to the PCB. You may want to find someone who has soldering skills as this procedure is fairly delicate. Needed is the correct soldering iron, not too big and with a temperature control. Since the pins are quite close, care has to be taken not to create solder "bridges" which are unwanted paths between the connections. Sometimes removing an existing connector is more difficult than indtslling a new one.

If the problem is intermittent, sometimes the corrective action is to carefully heat up each of the solder joints .(i.e. - re-solder) the solder joints. Again you do need the proper tools. When I do projects like that, I use a lighted magnifying glass. and try to have the PCB held by something such as a small vise.

Rgds,
Ed

Re: Pedal board MIDI connector help

PostPosted: Wed Aug 12, 2020 1:14 pm
by srw647
Nick - many thanks. The part you suggested wasn't the right one, but much closer than the ones I'd found. We've used it as a hole punch to bodge another emergency repair with blu-tack and a fresh matchstick, and I'll leave well alone for the next few months!

Towards the end of the year there will be a bargain console available for someone who's either willing to put up with a pedalboard that works but really needs attention or who wants to redo it properly.