The Sinclair QL Forum

I presume this is some custom industrial expansion board - Does anyone knows what this might be? Probably servo motor control as steppers were not so prevalent back then when CNC were coming in.
https://united-kingdom.exportersindia.com/stebon-ltd/
https://www.daxautomation.co.uk/part/parker-pks ...

I thought you fixed this site so it doesn't hammer the CPU for no reason. There is something fundamentally wrong. See the system usage pictures from the BBC and your site. Lots of pictures refreshing on the screen requires work on the BBC site but then no more resources are required by Web or ...

tofro wrote: Wed Oct 04, 2023 11:16 amThere are so many potential reasons for problems that you will have a hard time finding them with an "all-at-once" approach.

It is exciting to see what goes bang.

I found this on the setup pages. I don't fully understand it but it suggests that maybe I shouldn't use the twin drives (or is it OK as I have 3.5" drives)?
If using 3.5-inch and 3-inch drives, this is not a concern. Their terminations are weaker and cannot be disabled.
The weak terminations ...

You say
I believe the QL drives use the Shugart interface (they work with my SGC and SQB so... yes?). However, as they have a dual floppy ribbon with single connector, can I use them with the greaseweazle?
and greaseweazle says "Floppy drive – any 5.25″, 3.5″ or 8″ floppy that uses the Shugart ...

I finally wired up the PIC interface board that will convert the QL membrane input pins to give me a serial input that I can connect to a computer. After belling out all the wires I flashed a chip with my first version of software stuck the 5V from the QL on it and the 10 MHz oscillator is running ...

Thank you. This can give me peace of mind until I find an original power supply. By the way, I'm aware that the original spectrum power supplies are not very reliable; I don't know if due to the fact that they were built on the cheap or simply the capacitors need to be replaced (perhaps both). If I ...

output voltages from the plug: on the blue I have 18.5 V alternating current and on the red 7.6 V direct current. When I was fixing my PSU these correct values were quoted.

Around 16v AC sounds about right for one of the required voltages. There should be about 16v AC and 9v DC and on the plug ...

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 ...

I will re-align the lower chip. That original 74HCT157 on the bottom row was actually totally dead. My tester didn't recognise it as any kind of 74x chip. The replacement tests fine. The burnt left hand joint of the three on the ribbon PCB looks cracked but it could just be a ring of flux. For ...