The Sinclair QL Forum

For some reason my main QL is prone to a bent pin (always the top left as you look inside) and I'm desperate for some method to protect the pins on my QL expansion port

Without any availability of any QL backplanes I'm thinking of some kind of PCB that is simply a male/female DIN at each end

I had thought of using a modern memory board I have spare (sort of), but I don't think the SGC would like a memory card between it and the QL? or would it ignore it?

I can find PCB's available (though I've got to check size would fit in QL) and right angle 64 way male connectors are available everywhere but I'm really struggling to find female ones (mouser seems to have them but they have so many from the same manufacturer that I don't know what to pick! I assume Amperage etc. come into the choice?)

Obviously given my lack of any soldering (or electronic) skills this is going to be a challenge for me, but I can at least check continuity of every pin when I've done

I was wondering if anyone has any advise on which connectors (male and female) to actually buy please?

Many thanks
Tony

Have managed to find what I think are the correct connectors at RS

But the board I've found so far is 16cm long!

Usually pins bend because you don't insert the card straight, perhaps a plastic or wooden block as a guide, glued to the case, will help to insert the card correctly.

Also one time you bend a pin, usually bend again so another solution is to replace the complete conector in the QL.

My memory expansion board (available in GitHub) is about 5cm, (I can design you one of the dimensions you want, is very simple).
Using a unpopulated PCB of memory expansion is also a solution, but you are extending the wires more than necessary and in some cases can cause problems (reflections).

aalea wrote: Thu Apr 03, 2025 4:29 pm Usually pins bend because you don't insert the card straight, perhaps a plastic or wooden block as a guide, glued to the case, will help to insert the card correctly.

Also one time you bend a pin, usually bend again so another solution is to replace the complete conector in the QL.

My memory expansion board (available in GitHub) is about 5cm, (I can design you one of the dimensions you want, is very simple).
Using a unpopulated PCB of memory expansion is also a solution, but you are extending the wires more than necessary and in some cases can cause problems (reflections).

Thanks

I can't even contemplate taking a soldering iron to the QL motherboard

But do you mean I could just remove the memory chip from one of my expansion boards please? (I'm assuming the memory IC is the socketed IC)

t0nyt wrote: Thu Apr 03, 2025 4:38 pm

aalea wrote: Thu Apr 03, 2025 4:29 pm Usually pins bend because you don't insert the card straight, perhaps a plastic or wooden block as a guide, glued to the case, will help to insert the card correctly.

Also one time you bend a pin, usually bend again so another solution is to replace the complete conector in the QL.

My memory expansion board (available in GitHub) is about 5cm, (I can design you one of the dimensions you want, is very simple).
Using a unpopulated PCB of memory expansion is also a solution, but you are extending the wires more than necessary and in some cases can cause problems (reflections).

Thanks

I can't even contemplate taking a soldering iron to the QL motherboard

But do you mean I could just remove the memory chip from one of my expansion boards please? (I'm assuming the memory IC is the socketed IC)


IMG_4646.jpeg

Just realised the socketed IC is the GAL

Don't want to destroy the card so will leave it "as is" and look for another solution

Many thanks

Removing the gal and put a jumper of cable between pin 19 and 20 of the gal socket shall be enough to disable the ram, but I was talking about a new PCB without any soldered but the 2 connectors.

aalea wrote: Thu Apr 03, 2025 9:08 pm Removing the gal and put a jumper of cable between pin 19 and 20 of the gal socket shall be enough to disable the ram, but I was talking about a new PCB without any soldered but the 2 connectors.

Ok, thanks

Having slept on it, and as I don't have any MDV's to recover at the moment, I'm going to just leave the SGC in the QL and just not remove it to keep the pins safe

As I'd really like to be able to plug in both the SGC & Qsound at the same time I'm going to look into getting parts to make a "simple" 2 port backplane (which will also therefore protect the QL pins). I've been reading a couple of interesting threads on here that make me think this may be possible without any other electronics

Though having said all that, as it's non-destructive, I may try modding the memory board as per your description, as a stop gap, to allow SGC removal for MDV recoveries

Many thanks all

Note the DIN 41612 (the cheapest ones, and that is what I would expect Sinclair has selected) are specified for only 50 (!) insertion/extraction cycles by their data sheet. So, you wouldn't want to constantly swap cards anyhow.

Have you contacted tetroid for one of his backplanes?

t0nyt wrote: Fri Apr 04, 2025 8:06 am As I'd really like to be able to plug in both the SGC & Qsound at the same time I'm going to look into getting parts to make a "simple" 2 port backplane (which will also therefore protect the QL pins). I've been reading a couple of interesting threads on here that make me think this may be possible without any other electronics

AFAIK is not possible to install the Qsound along with SGC (or with a trump card), they don't have the mechanism to reserve the memory need for the interface.

I only ckeck it to work flawless with the 512Kb Ram, Qbide and qimsi.

It should work, using a special backplane (mandatory) with CST's Disk interfaces, and probably cumana or any other interface that have a 74LS266 IC near the QL conector, but not tested.