Intermittent floppy disk drive problems

[georgeo]

Hi Robsoft,

This is a very generous offer. I'd actually offer to do the opposite and send my card and disk unit to you, assuming you were happy to spend the time testing. However, given that your QL is off for an MOT, that isn't much use.

Let me follow up with the Ben and Vitaliy over the next day or so--they've both being trying to help over the last couple of days. However, if I can't make any progress, I'll take you up on your offer.

The issue has been niggling me this morning, though I realised something that may point to the Trump card being the problem. Specifically, the only way to recover from the problem is to reset the QL. Once the problem occurs, and it can be from power-up or after a period of use, it looks as if the drive becomes permanently inaccessible. Power-cycling the drive unit doesn't help, nor does wiggling the cable. The only fix is to press the reset button on the right-hand side of the QL.

Given this, I wonder if this is actually pointing to a problem with the Trump card, even though I don't see the problem with a different single-drive unit.

Anyway, thanks again for the offer. It is much appreciated,
Georgeo.

P.S. It will be interesting to hear how your MOT goes. I'm stuck with a UHF output, due to the compatibility of my monitor, and I wonder if re-capping (and possibly disconnecting the UHF to give a composite output) would improve the picture somewhat. Anyway, this is for another day, once I've got the disks running smoothly.

[robsoft]

Cool - and I'll keep you informed of when my QL comes back, if it's not too long gone then me testing them for you might still be an option. Happy to help whatever way etc.

As for the display - I'm using a cable from the RGB socket to a SCART plug, and that's going into my cheap-ass old 'portable' LCD telly that happens to have about a million different inputs. I can't use it in monitor mode, even going through a SCART-HDMI type connection I still lose a little bit of the right hand side of the monitor-mode display (and without the SCART-HDMI box I only get the standard 'middle' bit of the monitor-mode display, of course) but it's fine for use in the 'TV' mode and I get a really stable, solid picture. If you're using an RF cable, then I'd highly recommend getting the RGB-SCART cable when you have everything else working, it's a real marked improvement.

Anyway, that's a distraction. Good luck with Ben and Vitaliy, keep us in the loop, and if I can help do let me know!

[georgeo]

Hi everyone,

With help from various others, including Robsoft, I've been able to narrow the problem down to the disk unit. I've tried two different QLs, two different Trump cards, and two different disk-drive PSUs and always see the same intermittent access problems. I also tested the QL PSU and confirmed voltages are in line with specification.

The only change that makes any difference is using a different disk drive. I have tested with three different units -- the believed-to-be-problematic double-drive unit, a double-drive unit that I borrowed from Robsoft, and a single-drive unit from a friend in Edinburgh. Sadly the three disk drives are all different (and have different power supplies). However, the two I have loaned both work without any problems.

The believed-to-be-problematic unit is back with the seller who is testing it, trying to find the problem. However, they have yet to find a fault. They don't have a QL to test on, so I wonder if there is something about the way that the QL/ Trump card access a disk drive that is unusual -- so not picked up by testing with a different computer, or potentially leads to an unusual incompatibility with a small number of disk units.

Happy to hear any ideas! Thanks again,
George.

[georgeo]

Adding to my previous post, I can confirm that the seller is testing the disk drive with a PlusDlite interface on a ZX Spectrum. The drive unit appears to be problem-free with that setup.

Does anyone know of any potential differences between how a Trump card accesses a disk drive and a PlusD interface does, which could explain the reliability problems I'm seeing?

Thanks again,
George.

[bverstee]

Hi George and other readers,

I'm currently testing George's Dual floppy drive set I sold him, but as he said already, I can't find anything wrong with it.
Of course I will replace the set, but it would be a good thing to know why there are problems with his QL and Trump card.

I'm testing the Dual floppy drive set on a ZX Spectrum with PlusDlite disk interface.
This is a Shugart compatible disk interface.

As far as I know the Trump card is Shugart compatible as well.
This is proven by it working with the Dual floppy drive set in the first place, but somehow after some minutes problems appear.

I have some QL's and Trump cards, but I haven't ever used them.
George gave me a test description, so I might get out a set and test it this week.

I wanted to check the pinout of the floppy connector on the Trump card, but can't find a document describing that.
Does anyone have that information?

[tofro]

Ben, (Assuming you are Ben Versteeg given your user name)

although it might help neither you nor George much forward in finding the actual problem but needs mentioning:

I do have the exact same setup that George has. QL JS-ROM, Miracle Trumpcard, and your dual floppy drive set (It took me a while to realize I actually bought it from you some time ago ). And have no problems with that set-up whatsoever. Works after booting, works with both drives, simply works, and flawlessly. With that set, I was even able to read some floppies 30 years old that I had set aside for recovering with the sector editor because I couldn't read them with my other drives...

This at least should exclude any general incompatibilities in the set.

SHOULD WORK. (Famous last words...)

Tobias

[georgeo]

Hi Tobias,

This is very useful in that it seems to rule out the possibility of an incompatibility between the Trump interface and the disk unit. The only subtle difference I note is that I am using a modern-day Trump card clone, rather than a genuine Miracle Systems device. Also, I'm not sure what version of the QL ROM my system is running. Is it straightforward to check this?

Ben has set up a QL with a Trump card and is now testing the disk unit that I returned to him. So far, he has been unable to reproduce the problems I faced.

Thanks,
George.

[tofro]

George,

Version check ist straightforward, just do

Code: Select all

PRINT VER$

And my dual floppy set works equally well with the Russian clone and "the real thing".

Tobias

[georgeo]

Hi Tobias,

Thanks. I'll check whether my system has the 'JS' ROM, which I assume is the most common?

Thanks again,
George.

[tofro]

Thanks. I'll check whether my system has the 'JS' ROM, which I assume is the most common?
.

"JS" is indeed the most common, (and also the most stable and last official UK version) closely followed-up by JM, its predecessor. Last version overall was MG, which was officially released only in foreign language versions.

Tobias