The Sinclair QL Forum

Hi, I am a new QL user and have a couple of problems with my upgrades:

Minerva
I wanted to replace my original ROM (AH) with Minerva and it went well until I tried to run programmes. It turned out I cannot load much from my microdrives, except short superbasic programmes. Commercial software would load forever and then return a message "at line ... out of memory" and then referred to the line which had something like r=RESPR (77000). I watched Noel Retro Lab's video on youtube and got an explanation - it seems my QL motherboard would need some more tinkering than just replacing the ROM chips. OK, so I changed the ROM back to AH. But a very similar problem persists. This time I get the line "bad medium" or "out of memory" with a reference to LBYTES or EXEC commands. At least microdrives seem to function ok. What needs to be done to be able to run software on QL again?

vDrive
The QL often fails to detect that there is an MDV3_, so have to switch it on/off a couple of times. And then the problem is that it doesn't detect the SD card - but here Charlie Ingley suggested to use a Sandisk 4GB SD card, which is on the way from China, so that should solve the problem with the SD card.

Expanderam
Strangely, when I insert the Expanderam into QL, the signal weakens and the screen becomes snowy. The only remedy seems to be to boost the signal, but I am wondering why that happens in the first place. Expanderam seems to be okay (Minerva tested).

I would be grateful for any feedback.

Cheers!

AndyZX wrote:Expanderam
Strangely, when I insert the Expanderam into QL, the signal weakens and the screen becomes snowy. The only remedy seems to be to boost the signal, but I am wondering why that happens in the first place. Expanderam seems to be okay (Minerva tested).

Perhaps give a little more data like what version of motherboard you have and explain "signal weakens". If you mean the UHF levels get affected then check the power supply rails that might be loaded by the extra circuitry. The ROM problems sound like pin connection problems but if the ram checks work then more testing is required for more pointers.

Thanks for your reply. The serial number is D09 015124. ROM chips are made in Korea-A, 1983. I don't know what the motherboard issue is but attach a picture if that gives any info. When loading software I usually get this error message "280821 bad or changed medium". I might have swapped IC33 and IC34, not sure, - would that make a difference?
I also attach pictures with Expanderam plugged in - without it the TV picture is okay.

This all sounds (especially the last) as if your power supply might live a bit on the "weak side".

How do you power the QL?

Does the situation worse when the computer warms up?

Are you able to check the +5V, +12V and -12V rails' voltage (with a multimeter or the likes)?

One of the caps in the voltage regulation circuitry or the 7805 could have gone weak and close to end its life.

Hi,

Looking at your picture of the board. the board issue number is next to the Sinclair name, infront of the SER sockets.

Your board is an issue 5.

The QL Roms are:

QL AH 0000 low rom
QL AH 8000 high rom

The picture shows the roms in the wrong sockets, switch them over to see if that works any better.

AH Roms are not good, they do not link RESPR additions correctly, so NEW had be entered before it will work , this is a bug in QDOS.

Minerva should fix all this.

Try cleaning all the plugin chips and press the chips into sockets, same for the Exander Ram.

Get another power supply to try.

The picture shows the decoding IC for the ROM's is not fitted - you have only a socket, this means the board's wire jumpers - actually they are 0 ohm resistors between this socket and the 1st ROM socket - are set for ROM chips and are therefore wired identically - the ROM chips themselves decode for the upper or lower portion of ROM space - one is 32K in size, the other is 16K. Minvera ROM is 48K and is on a board to decode itself correctly - it will work in either socket

Thanks Tofro, Derek and QLDCXL for your useful feedback.

The power supply is the original UK and I have a European converter. Unfortunately I don't have the equipment to check the voltage.

It all functioned well until I decided to change my AH ROM for Minerva. (The only other thing I did in between was to replace the keyboard membrane.)

I retried (with Psion Chess, Assault & Battery and Spook), first putting in the AH ROM in the right order as pointed by Derek. The message was "bad or changed medium".

Then I changed for Minerva ROM and it is as before - infinite loading or "out of memory" error message. (Minerva as such seems to function well, it shows 128K on the initial screen.)

Could it be that my board issue 5 would need some additional tinkering to run Minerva? I think this is the point that Noel makes in his lab video. (https://www.youtube.com/watch?v=0z4X4AMKlcs, after 15.40)

This would explain problems with Minerva but I am still wondering why reinstalling AH ROM would not work - previously I could load programmes without any problem.

Minerva photos attached.

I would say nothing is wrong with your Minerva - but it's only seeing 128K RAM - so presumably your expanderam is not plugged in at the moment.

That leaves the vDrive - is it this you are loading your Microdrive images from? or from the Microdrives themselves? Is the vDrive installed?

Pr0f wrote:The picture shows the decoding IC for the ROM's is not fitted - you have only a socket, this means the board's wire jumpers

No mention of this so is that a preconfigured jumper block that gets soldered in like a socket but contains shorts for required jumpers?
Is the resistor mod on the top of the chip required or is it different on a series 5 board and fitted somewhere else?

Yes, the configuration on pics is without the Expanderam and vDrive. When Expanderam is plugged in Minerva shows 640Kb, so memorywise things are okay.

If I have to identify THE problem it is about loading from microdrives as described above.