Spem QL keyboard

[Delta]

Hi all,

Could somebody point me in the right direction regarding connecting a SPEM QL keyboard please? It is such an improvement over the standard QL one that I would really like to use it.

Thanks.

[Chr$]

They have a ribbon cable coming out of them with a long flat PCB at the other end that just plugs into the 2 k/b connectors on the QL motherboard. I have one and have replaced all the keyswitches with clicky ones (available new, brand Futaba).

[Delta]

I didn't realize it was that simple.

Unfortunately, after connecting it and checking the connector on the keyboard side, the keyboard doesn't register any key presses.

OK...does anyone know the preferred troubleshooting method for these keyboards?

[Ruptor]

OK...does anyone know the preferred troubleshooting method for these keyboards?

Assuming the QL motherboard works the keyboard is just a bunch of contacts so you can use a continuity meter between the 9 & 11 way connections then press a key to make the contact. Pin 9 on 9 way & pin 1 on 11 way with the CTRL key pressed should give a continuity.

[Chr$]

They tend to expand the contacts on the QL connectors more than the original plastic membrane. I had to replace both my QL connectors. Take the Spem apart and also check that the ribbon cable is good by checking continuity from the k/b end to each pin on the little PCB end.

[Delta]

I have checked continuity between the motherboard pcb connector and the keyboard solder joints and there is connectivity on all the pcb pins although strangely, I found that some pins register on more than one solder joint on the keyboard side? Is that normal? Such as pin 4 of 11 on the pcb registers with contact 4 + 5 on the keyboard side.

What is more concerning is that when I make a direct connection on the underside of the keyboard pcb between the key solder points, I receive nothing.

[Chr$]

I don't think it should be like that, each should be separate. Is the little Spem plug-in PCB not aligned properly? With nothing plugged into the QL are those pins also connected? Does the QL (and its k/b) work properly with a normal membrane k/b attached? Sounds like your going to have to spend some time tracing/checking and all that good stuff.

Here is a pic of part of my Spem PCB underside.

Is yours the same? The top red rectangle highlights the 20pin connector that the ribbon cable connects to (that ends up plugged into the QL). Mine had bad dry joints there. The lower red square is the 3 prongs of an individual key - top and lower right are common as they are connected within the keyswitch. Lower left and either of the other pins are the actual switch so should show continuity when the switch is pushed down. Lots of mine didn't.

[Delta]

Is the little Spem plug-in PCB not aligned properly?
It does seem correctly aligned and doesn't suffer from having pads that are too large.

With nothing plugged into the QL are those pins also connected?
My previous results were based on the keyboard being disconnected.

Does the QL (and its k/b) work properly with a normal membrane k/b attached?
Yes.

Sounds like your going to have to spend some time tracing/checking and all that good stuff.


Here is a pic of part of my Spem PCB underside.
Is yours the same?
Yes.

My 20 pin connector does not seem to have any dry/bad solder joints.

Like yours, most of the keys do not make a contact but I have found some that do! It feels like a minor victory. Those keys however still don't appear on screen.

[Chr$]

So on the 20 pin connector, with the ribbon disconnected, do you have some of those pins shorted?

If you can get the working keys to appear (I assume you're using Minerva so that it automatically gets you past the F1/F2 prompt), then I probably have some spares that work. They are pretty much impossible to open up to clean the contacts.

[Delta]

I have attached an image to show the conductivity between pin blue and pins red.

This may not be relevant but I think this is what you are asking?

Yes I am using the Minerva ROM.

Thank you for the offer of the keys, it is very kind...but something is telling me the problem isn't with the keycaps.