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keyed incorrectly?
MUFF WIGGLER Forum Index -> Eurorack Modules  
Author keyed incorrectly?
loudone
I have a module i wanna plug in and play with but i believe the doepfer connecter on the ribbon is keyed incorrectly.
If i put the red to the top( I have an Asys rack) the slot don't match. The rest i have in do?
Should i just switch it on the module so the keying will be correct. The red stripe will be on the positive side, will this matter?
itijik
It shouldn't matter if you switch it on the module side, but I would be careful doing that...don't forget about it later! Dead Banana
loudone
i am so anal anal about frying modules. i would most likely cry lie a girl cry
especially a 400 dollar module!.
i would freak!
thanks, umm itijik, i will probably marker the cable to remind me!
anyone else wanna stop me before i do f something up?
tony d
I think 1 of the cables on my afg was like that, and just discovered the polivoks is also.
I just wrote with a marker on the cable so i don't forget if i switch it around again.
REwire
I come across many modules keyed wrong for my ASys cases. Step one is to take the cable off and put the side that connects to the buss board on the module still with the red line in the right place on the module and see if the other side is keyed right. Usually it means flipping it over backward so the cable is bending from back over the PCB where it came straight out before. Most cables will have one side keyed right.

If that doesn't work I will decide that the red line will now be down and will be properly plugged in but red line opposite on the module and in the case.

the good thing thing about Asys cases is a fuse will blow immediately if you plug it in backwards and save the module.

Good luck, Dan
wetterberg
"will it matter?" - well, that depends on the module, hehe.

Which module is it?

Can you get a closer look at the traces on the pcb? Usually the giveaway is that 5v and gate (on the ribbon cable) isn't being used, so that gives you an solid idea of the direction of the cable.
worker8
paults
In order to plug into an AS power supply, a *non-AS* module's power cable *must* be 'inside-keyed'. That is, on the power supply end of the cable, with the red stripe "down", the connector key is towards the inside (under the ribbon cable) and NOT on the outside.

The stock Doepfer power cable is 'dual inside keyed', meaning both ends have the key facing to the inside. They can get away doing this because on Doepfer modules, the power connector on the module itself is *unkeyed*, it's a plain, unshrouded 2-row header. So, *technically* this is a 'flip cable' connection (pin 1 is now going to pin 16, *electrically* and with respect to *the connectors on the power cable*) it works because Doepfer 'defeats' the keying scheme on the module itself.

Does this seem overly complex, confusing and a bit......stupid? Yes, it does. Whoever originally decided all this crap did a *horrible* job at system-level engineering. Just sayin' Dead Banana

After thinking about this for seveal *days* I decided to do it properly in my Euro modules at least. I will use a keyed, shrouded header on my module that 'forces' my shipped power cable to have 'red stripe down'. You can use a stock Doepfer cable with my modules: I allowed room on the pc board to allow for the cable to flip back over' (plugging an inside-keyed cable into my board means the cable then 'exits from the right side' of the pc board, and you have to bend the cable back towards the rear of the case). The power supply end is properly 'inside keyed' so it can plug anywhere (AS or Doepfer style supplies) and be correct. I have protection diodes reversed-biased on the board so that if you manage to plug it in wrong in a Doepfer system (you can't in a AS, they use the keyed connectors) the supply will 'crowbar' (drop the output voltage to a low value, like 2V) and then you will notice that and turn off the power (AFAIK, Doepfer supplies have no fusing mechanism).

If you unplug my cable from the module and later forget 'which end goes where':

a) in a Doepfer scheme it won't matter as it's unkeyed and it's *still* up to you to put the 'red stripe down' (and also not 'pin-shift' the connector, meaning you accidentially move the connector off-center on the power board). This is why they *invented* shrouded headers in the first place (and no, they are not that much more expensive.....give me a break)

b) in an AS system if you 'guess wrong', it doesn't matter because I use 1:1 wired cables. What you will notice if you are paying close attention is the power cable will 'exit' the AS power connector from the opposite side but it's still powered OK.

Lastly, I was annoyed that no one I saw (Plan B, Doepfer, TipTop, etc) used proper strain reliefs on the cable connectors. So I'm paying the 15 cents more to add them nanners
loudone
paults
bit confusing....
It is a harvestman module. I flipped the connector on the module side, marked the cable and then inserted it so red side on module is cabled up in the asys case.
i hope i don't smell burning electricity in a minute
very frustrating
daverj
paults wrote:
In order to plug into an AS power supply, a *non-AS* module's power cable *must* be 'inside-keyed'. That is, on the power supply end of the cable, with the red stripe "down", the connector key is towards the inside (under the ribbon cable) and NOT on the outside.


Sorry, but by itself, this is not enough information for people to get it right. And in fact adds a layer of confusion that could blow up modules.

It's not an issue of being "inside" or "outside" keyed at the power supply end. It's a matter of the key itself facing left or right when the red stripe is down and the connector is facing away from you.

Ribbon cable can enter a ribbon connector from either the left or the right. In both instances the same wires of the ribbon connect to the same pins of the connector.

With the ribbon entering from one side, the key is on the inside and with the ribbon entering from the other side the key is on the outside. Both cables are electrically identical and both work exactly the same. (I'm talking about the power distro end only. I'm assuming that the module end is already connected correctly to the ribbon)

Look at the picture below. Both connections are identical. The red stripe goes to pin one of the connector. Either of these plugged into a shrowded header with -12v on pin 1 will provide -12 on the red stripe. But one if these is inside keyed and one is outside keyed.


paults
The picture above is how my cables are connected: wired 1:1 with 1 inside (the 'power end') and one outside (the 'module end') SlayerBadger!
daverj
The above picture was meant to represent the power distro end only.

My whole point is that telling people to make the power distro end "inside" keyed and not "outside" keyed is not true and will cause confusion, since that end works exactly the same whether keyed inside or outside, as long as the red stripe goes to pin one of the connector.

Maybe this picture will explain it better. I didn't bother to crimp them. In all 4 cases the connectors at the ends are facing exactly the same way with the keys in exactly the same positions.

There are 4 ways to run the ribbon between the connectors, all result in exactly the same electrical connection. Pin 1 is always at the red stripe.

Inside and outside are irrelevant.

dkcg
I Dremel off the key with a sander bit on non-conformist cables. I'm too afraid I'll forget I swapped the cable backwards, and it only takes like 2 seconds, takes longer to secure the cable down than it does to sand it off.

It's only a problem in ASys power busses, and maybe ASol busses (don't have one so I can't check).
paults
Well, you cheated hyper

The 'cheat' is flipping the *cable* (not the connector) so that Pin 1 is by the red stripe.

Look at a standard Doepfer cable. Pin 1 goes to Pin 16, Pin 2 goes to Pin 15, etc. on *the cable itself*, not "in the system". So, the *user* has to do the cable flip themselves (or sand off the key, or use non-keyed connectors).

Yes, the the 4 cases you presented, they will all "work". But there are 2 *other* cases that are flipped, and Doepfer is one of them. And we haven't even addressed cases where the 2 connectors point 'up' and 'down' very frustrating

My point is this: it's a stupid, confusing power distribution system that should have *always* been properly keyed using 1:1 cables from Day 1. But it's not, and that's a shame. Most people don't care about this level of detail: I've been worrying about this level of detail since 1977 Dead Banana

The freakin' LHC blew up $10million of power supplies, magnets and cables because of this sort of "boring" level of detail.
dkcg
paults wrote:
The freakin' LHC blew up $10million of power supplies, magnets and cables because of this sort of "boring" level of detail.


That's a lot of PowerOnes, and like all of AdInfinitum's cables. hihi
That ground will get ya every time...

I think the best rule of thumb is just be consistent in all your cases. I use the redstripe = -12V on doepfer style cases, red stripe = 0V in ASys cases "standards" and just pay attention on the PCB and the power bus. Especially since keys and stripes are not always consistent. As long as the PCB is marked, it's all good.

Definitely one race slow and careful wins.
daverj
I just looked at two Doepfer modules and both have ribbons that have pin 1 of both connectors at the red stripe. These ones are not pin 1 to pin 16, etc...

Since Doepfer distros aren't keyed I can imagine there have been Doepfer cables made with the connector on upside down and it made no difference to the user as long as the red stripe was down on a Doepfer distro. But that's not the case on the two Doepfer cables I just looked at. (of course, the connector on upside down would matter if plugged into a shrouded header)

There's no cheating in what I posted. The cable isn't flipped. It just enters from the left side of the connector or from the right side. There is no difference electrically.

Here's one last pic to try and explain why "inside" and "outside" keying are not a valid way to define how to make the cable end.

Imagine that you are standing behind the distro board, looking through it at the connector plugged into it. You have two cables and the module end of those two cables are identical.

The distro end of the two cables are made the two ways shown in the photo below. One is "inside" keyed, one is "outside" keyed. There is absolutely no difference between how these cables work. They each have pin 1 to the red stripe at this end of the cable.

(these are actually 14 pin connectors & ribbons since that's what I had handy to photograph)



I agree that if the connector is put on wrong (red stripe to pin 16), then the key is facing the wrong way and there is a problem plugging it into a shrouded header correctly. But that isn't what I'm talking about. What I'm saying is that "inside" and "outside" keyed are not valid ways to describe how to put the connectors on. You can have the inside/outside correct and still have the connector on backwards, and blow up the module.

Defining the connector on the distro end of a ribbon as being inside or outside isn't going to get that connector onto the ribbon correctly. You have to explain where pin 1 of the connector is and make sure that the red stripe goes to pin 1. Inside/outside doesn't matter.
paults
Hmmm...my Doepfer cable is not 1:1. It has both connectors pointing "down" and both keys inside. So, it *can't* be a 1:1 cable.

I have a Plan B cable that has both inside BUT one end 'points up' and the other 'points down' which IS a 1:1 cable.

BTW: for those of you who don't know, pin 1 is maked by a small triangle molded into the connector body. And, industry standards have always been that if you are holding the cable vertically (up and down) Pin 1 is on the rightmost, top row (top row meaning away from the cable entry).

This is much more fun to discuss than 3rd order Legendre polynomial curve-fitting algorithms used in the MT eek!
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