Problems with/after ROM replacement, vDrive and Exapanderam

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Martin_Head
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Re: Problems with/after ROM replacement, vDrive and Exapanderam

Post by Martin_Head »

For a quick check on the RAM. PRINT PEEK_L(163872) should return 262144 ($40000). According to my QDOS companion.

Also as PrOF said earlier, I wonder if you have power supply troubles. It may measure OK on a meter, but if the supply has a bit of ripple on it, It may be dipping below the threshold of the 5 volt regulators, or causing variations in the speed of the Microdrive motors. The Electrolytic capacitors in the PSU may be drying up after all theses years.

You refer to ALCHP. Do you have a Toolkit 2 ROM installed? If so try removing it. It may be using a bit of RAM which upsets some programs. Although I would expect Quill to be OK.


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AndyZX
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Re: Problems with/after ROM replacement, vDrive and Exapanderam

Post by AndyZX »

Martin hello and thanks for the suggestions. I checked RAM with a peek and it returns the correct number (262144). As to the power supply I am sure my colleague checked it (he made a thorough check and replaced some old capacitors) but I will ask him again, also to check the PSU capacitors. No, with AH ROM I have no toolkit installed so this should not be causing me problems.


Martin_Head
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Re: Problems with/after ROM replacement, vDrive and Exapanderam

Post by Martin_Head »

Looking at the screen dumps you supplied.

The Quill one says it's from PDQL. I don't know if there is anything special about that. What is the file size of MDV1_QUILL ( I know that might be a bit awkward without Toolkit 2)

The QL cavern one, What if you reset the QL and type r=RESPR(72000). Does it work OK. What else goes on in the boot file before line 300. Can you try to reproduce it, to see what goes wrong, and where.

I don't have any experience of the vDrive, but I had a quick look at the online manual. It talks about loading a toolkit with LRUN mdv3_boot. Are you doing this? If you are loading a toolkit into memory, then you might not have enough room left for some programs that want a lot of the 128K available.

As far as a power supply problem goes, and someone else on the forum may be able to confirm this. I think you can run a QL on just a 9 volt supply alone. The serial ports won't work, and I don't think you get any colour from the RF or composite video out. But the QL will run.


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dilwyn
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Re: Problems with/after ROM replacement, vDrive and Exapanderam

Post by dilwyn »

PDQL Psion upgrade advert
PDQL Psion upgrade advert
Martin_Head wrote: Mon Jan 02, 2023 11:18 am Looking at the screen dumps you supplied.

The Quill one says it's from PDQL. I don't know if there is anything special about that.
PDQL got hold of copies of the latest (at the time) Psion programs and offered them as upgrades at a modest charge. IIRC, nothing special in these, just that they were slightly more recent versions than were in general circulation at the time. PDQL added their name to the boot programs, I'm sure that was the only "change".
Edit: forgot to include the scan of the advert showing the versions PDQL offered at the time (October 1989). In the same issue of QL World on page 28, there was an interesting article which discussed the new features available in Archive v2.3 at the time,, in particular the new screen driver features.


af0l
ROM Dongle
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Re: Problems with/after ROM replacement, vDrive and Exapanderam

Post by af0l »

AndyZX wrote: Fri Dec 30, 2022 9:58 pm Thanks Derek, will fix Minerva and put the resistors on the top of 8302 - hope that will solve the problems.
Hi, just to add my five cents as I am the perpertrator of the aforementioned mods. The resistors are there, I put them underneath the ULA, so it can be replaced if needed. Minerva fixed, no help at all. I hooked the scope to the MDV's and everything seems in order, as far as I can tell. Luckily, AndyZX had the common sense to inlude his vDrive in the package - so I could test out this theory I had, that the drives were actually OK and the cartridges weren't. As it turned out, I could not read the cartridges in my machine, but that is heavily modded and has trouble with mdv's. But the cart formated in my machine, overwritten in our patient (from vDrive) just works! Seing that, a quick research on the forum got me adjusting the motor speeds and formating like a maniac - all the formated tapes work now. That original still doesn't 🤦‍♂️

I am leaving this here for future reference - I hope someone finds this useful.


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