The Sinclair QL Forum

Hi,
There are some basis things to test first at all when getting a new old computer.
1. Power voltages from power supply.
2. Shorts in main board between power lines and GND
3. Measure of the power regulators inside the computer, in this case in QL the main one is the +5v from the linear regulator ...

A full memory test requires to:
1. Detect shorts
2. Fill the whole memory with at least 4 different basic patterns and read them are the same after it. "00", "11", "01", "10" and random. What takes some time.
3. In case of DRAM ICs, also check after a while the data remains (refresh).
4. If ...

I removed the soldered IC3 and replaced it with a socket. The chip tests as OK in my Retro chiptester pro! But it clearly isn't, or it's at least marginal in some respect.

And with a known working 4164 in the IC3 socket everything is fine.


Have you considered the idea that perhaps the problems ...

...
Unfortunately, with just the dodgy IC3 in place on its own, the Diagrom completed its tests and reported no issue. I'm not complaining of course, because as you say, the diagrom is just one tool is the diagnostic arsenal and whatever issue there is with IC3, it seems an unusual one.


It's a ...

Keep us update with the progress or what you decide to do.

It doesn't matter your level, if you want to learn, we could teach.

Hi :)

Firstly, I would not use any device with the QL till solve this video problem. Just for precaution policy


I seem to have a display cable problem. When I connected it to my (currently only working) German MGG QL the screen showed nothing (only green), but I know It has had worked with this ...

I bought the Voltage Regulator from Retroleum in the UK. If you search in this page for "MuRata OKI Switch Mode 5v Regulator for Spectrum 128 "Toast Rack"" you'll see it. Note, you're seeing the back of the regulator in the pictures of the QL I posted. I haven't noticed any new issues, e.g., snow ...

Well, you should put them back if you want reliable micro drive operations. They are not related to your problem, though.

You are right 100%.
But, since it is a problem that appears only after some minutes (very difficult one to find out), I prefer to set everything as it should.
I don't know as ...

No. This is how I got the machine. I think the mod may have been there in the past but was removed by the previous owner. What does the mod do? It doesn't prevent freezing by any chance does it?

You must place them.
It is for MDVs (if I am not wrong) but may affect other parts.



Is it ...

Also interested about this thread. I have been studying how it works in general.
My idea is to create (to try) a replacement, but only focused in the keyboard by now.