Core Electronics Forum

Looking for ribbon connector

Hi I’m looking for a ribbon connector Its for a Yamaha DX7iiD synthesizer.
2mm 12pin female. i need two

thanks

You could try Element 14 or RS Components for local suppliers. Maybe Mouser or DigiKey or similar
Cheers Bob

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Mike
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is pin pitch 2mm or 2.54mm. Element 14 (Farnell) have both. I would assume 2 rows of pins, single row would be 1.27mm pitch.
Are you going to fit these yourself and if so do you have any experience in this? If your answer is “yes” and “no” respectively be very careful. The connector has to be on the cable EXACTLY square. Tolerances on these connectors are pretty tight and a connector slightly off square WILL result in short circuits between wires. Also do not use scissors or any tool with a similar action as this will also have a good chance od shorts between wires. The special cutting tool has a blade with a cleaving action which comes down square onto an anvil type base and crops the cable cleanly.
As for the “proper” compressing tool. These are VERY expensive. If you are very careful you can get away with a small rise. It is very fiddly believe me. Whatever is used must close the connector squarely or damage could result. For a couple of connectors the vice method may do or you may be able to find someone with the proper tooling. You are fortunate in that you have female connectors. If you think about it male connectors are almost impossible without correct tooling or some form of jig.
Mike I am not trying to be a killjoy or put a damper on your efforts but am merely trying to help you avoid what can be extremely frustrating problems. I think anyone who has had to trouble shoot problems caused by one or more incorrect fitting in a ribbon cable run with multiple connectors will agree. It is often quickest and easiest to simply re-make the offending cable.
Hope this helps and good luck
Cheers Bob

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Hi Bob
Thanks for the info. Much appreciated. In answer to your questions, yes and no.
I would love to buy a replacement cable but it’s from a vintage synthesiser and Yamaha don’t make them anymore. I’ve asked everywhere And no one has one. I may be able to get it made once this Lockdown finishes (I live in Melbourne). But right now there aren’t any electronics companies open. I’m working on a deadline as I need this particular synth for a project which is the only reason I would consider doing it myself.

Best Regards

Mike Cook

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Hi Mike
Not a good situation at the moment. Particularly in Melbourne. Fortunately I live on NSW Central Coast.
If you have a deadline it looks like you will have to try and make this cable yourself. I will try to help if I can.

Firstly why do you have to replace this cable?
Is the original a) missing or b) damaged.
If damaged and the connectors OK it is often possible to recover the good connectors by carefully prising apart the insulation displacement (IDC) clamp and removing cable from connector. Carefully note the direction of cable exit WRT pin 1 or the locating key which is usually a raised part of the body half way down the length. This fits into a slot in the mating part so it can only be inserted one way. If this fails or can’t be done you will have to obtain and fit new connectors. At worst case the old cable can be a model to be copied.

If missing you will have to start from scratch.
Positively establish the connector pin pitch. You mentioned “2”. Is this 2mm or 2.54mm, both are available and of course are not interchangeable. Being a vintage piece of kit I would guess 2.54mm. I don’t know how long 2mm has been in use but you need to be sure of this.
Is strain relief required. Probably not. Some connectors are fitted with an extra clamp where the cable is doubled back on itself and held with this extra clamp.
When the correct connector has been established you need to get flat ribbon cable to suit. This also comes in 2 wire pitches, 1mm and 1.27mm. If you cannot get 12 core get the next available size up and strip some conductors off the side opposite the red stripe. This red wire by convention normally connects to pin 1. Better to stick with this to avoid confusion later.
How flexible does the cable need to be? Some of this ribbon cable can be quite stiff and does not cope with movement very well. Get a cable which will do the job.

Having obtained all the bits we can get started.
If you have the old cable for a model this will help.
Establish the required length and cut the cable accordingly. Do NOT use scissors. If the proper cutter is not available a good SHARP kitchen carving knife will do. Put the cable flat on a cutting board and cut straight down with the knife. DO NOT use a sawing motion but a cleaving action straight down. Giving the knife a rap with a piece of wood or something helps.
If the old cable is not available you will have to work out which direction the cable needs to exit the connector. This will be determined by the orientation of the mating connector in your equipment and will apply to both ends. Keep the red wire to pin 1 if possible. If it doesn’t seem right turn the ribbon cable over. The red wire business is convention but in practise it does not matter (except if someone else comes along later) as long as both ends are the same. Nicer to stick to convention though.

Time to fit the connectors.
This is where having female connectors is a help. You should get away with carefully using a small vise. Some help is advisable as it can be very difficult holding everything straight and square while clamping up the vise. Keeping everything straight and square is the key here. The proper clamping tools do this for you but unless you have a lazy $1K plus to spare the vise method will have to do. Do not use pliers as these will not squeeze the clamp up squarely. You can probably see here that the male connector becomes more difficult as a jig of some sort is required to do something about the pins.
You will note the shape of the wires is evident in the ribbon cable. The underside of the connector clamp has grooves moulded in it corresponding to these wires. It is important these wire shapes fit snugly into these grooves as this positions the wires correctly for the insulation displacement system to do its job properly.

Sorry if this is a bit long winded but I have tried to cover all I can think of on the assumption you have not done this before.

Cheers and good luck Bob

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Thanks bob but one of the female idc clamps is damaged. I think I’ll have to wait and get an electronics shop to replace the old male connectors and replace the whole thing.

Best Regards

Mike Cook

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Hi Rob,

That’s an awesome little write-up. It’s always great to see experienced Makers like yourself helping others out! :slight_smile:

I’m a big believer in ‘where there’s a will there’s a way’, but sometimes this is the most pragmatic choice. All the best with it!

Regards,
Oliver
Support | Core Electronics

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Hi Mike
Hope I didn’t frighten you off. Never my intention.
Have a go! As long as you are careful and don’t rush at it the job is not that difficult.
Great satisfaction when you succeed at the first try but don’t feel too bad if the first attempt is a bit off. We have all done that. I mucked up at the first attempt and I probably had a couple of thousand dollars worth of tooling at my disposal. The clamping tool wasn’t adjusted properly and I successfully flattened the connector.
Cheers and keep at it.
Bob

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Hi Oliver
Thanks for the rap. Not so much of a so-called “maker” these days as I just don’t have the space.
40 plus years of experience tho. Seen most of what Murphy can throw at you over the years.
Don’t mind helping out where I can.
Cheers Bob

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