Falcon bizarre floppy problem

[jms2]

Hi everyone, I'm a volunteer at Derby Computer Museum who has a fair amount of general experience fixing various types of machines. The museum is lucky enough to have acquired a Falcon in working condition, to which I carried out a PSU recapping using the kit from the Exxos store, and I also fitted a CF card and got it working using the HDDriver software. I'm not familiar with any Atari hardware, but so far, things seemed to be going well.

To summarise what I'm about to write, it's got a really bizarre issue with the floppy interface and I could really do with some advice please!

Having fitted the CF card, I decided to load some Falcon-compatible games onto it. To keep things simple I only downloaded about 3 games, all of which were small enough to fit onto one HD floppy each. I had no trouble loading and running them, and I also copied the content of the discs onto the hard drive.

At this point I started to get some clues that maybe not all was well with the floppy drive, but I didn't realise it at the time. First off, none of the games worked when run from the hard drive - I just got "TOS Error #35" when trying to load them. I thought maybe they just needed to be run from the floppy (but I now suspect that's not the issue at all, and that the files are corrupt). The second strange thing was that none of the games on floppy would load any more. I was able to format a disk and copy one game back onto it from the hard drive, and that game now works. But it's the ONLY floppy I can now get the machine to read reliably. I thought maybe my discs were just old and dodgy.

But... I'm now trying to get a NetUSBee up and running, which requires me to load its drivers from floppy. Here's what I'm doing, and what happens:
- Format HD floppy on the Falcon
- Write drivers onto it using Windows XP machine (with "real" non-USB floppy drive)
- Use hardware write-protect tab on floppy (I know this isn't necessary, but read on...)
- Open floppy on Falcon, everything looks fine.
- Open folder to check what's in it, again, looks OK.
- Copy folder to hard drive. No problems.
- Open folder on hard drive... hang on, some of the subfolders are missing!
- Open whatever subfolder is there - but there's nothing in it!
- Go back to the floppy to check what's missing - but now when I open the folder, there's nothing in it.
- I can't even close the floppy window, because every time I do, the Falcon attempts to read from the disc and throws up an error saying the disc might be corrupted.

I have tried with reformatting the disc etc, and I tried cleaning the floppy drive read head. No change.

If I take the apparently blank (according to the Falcon) disc back to my Windows machine, it's fine (it was write protected after all). If I switch the Falcon off and on again, the whole sequence starts again - the drive looks OK, but I can't copy anything off it, etc etc.

So then I decided to fit a Gotek (another job I'd been asked to do), to see if that makes any difference. I have a USB stick with various ST game images on (no Falcon games though). These games don't load (I'm not sure if they should be expected to), but I also get the same issue that the catalogue comes up OK the first time but then if you start digging around on the disc things mysteriously disappear and I get disc errors.

At no point do I see any actual corruption, files just disappear!

Anyone got any ideas?!?

[rubber_jonnie]

So if you're trying to get files onto the Falcon from your PC, the first thing I'd suggest is set up the CF card with HDDRIVER so that it can be read by both Windows and TOS, That way you can connect it directly to a PC and copy the files right to the card and they can also be read in the Falcon.

Of course, that's just general advice based on how I use my disks with HDDRIVER, however it would be worth trying and leaving the FDD out of the loop to see if the files stay on the CF card if the FDD isn't involved.

TBH I'm just spitballing here, as I don't own a Falcon, but it's weird as it sounds very like the ST 'DMA issue' with file corruption and missing files etc.

Just wondering if there are any other mods installed (Clock patch etc) and what is the 5v rail looking like, is it possible to adjust the 5v rail? Is the FDD cable known good?

[jms2]

Hi there, I notice you're a fellow Electron owner as well - was that also you on Stardot with the water-damaged Plus 1?

I haven't changed the floppy cable yet, but I am considering doing so. It looks fine of course.

The machine does have a clock patch fitted. Here are some notes I made on it:
It matches Atari's version 1.1 of the mod detailed on the page https://mikrosk.github.io/clockpatch/
There is an additional IC, a 74F08 (AND gate) mounted on top of U63 and connected to its power/GND pins.
R221 is removed.
R216 N to 74F08 pin 12 & 13 (inputs)
R216 S (via) to 74F08 pin 11 (output)
R221 S to 74F08 pin 9 & 10 (inputs)
R221 N to 74F08 pin 8 (output)
Other connections power the 74F08.

Your suggestion regarding HDDriver is a good one - the only reason I haven't done this is because I didn't fancy taking the machine apart to get at the CF card, thinking I could use the NetUSBee to transfer stuff across. I agree that it might be the way forward if the floppy problem is not easily fixable. I am pretty confident the HD works OK.

What is strange is that I was able to copy the HDDriver software from the floppy drive without problems. So it used to work better than it does now...

[smoore100]

https://joy.sophics.cz/parcp/parcpusb.html

This is what I use for file transfers, not the fastest but 100% reliable.

[rubber_jonnie]

Hi there, I notice you're a fellow Electron owner as well - was that also you on Stardot with the water-damaged Plus 1?

I haven't changed the floppy cable yet, but I am considering doing so. It looks fine of course.

The machine does have a clock patch fitted. Here are some notes I made on it:
It matches Atari's version 1.1 of the mod detailed on the page https://mikrosk.github.io/clockpatch/
There is an additional IC, a 74F08 (AND gate) mounted on top of U63 and connected to its power/GND pins.
R221 is removed.
R216 N to 74F08 pin 12 & 13 (inputs)
R216 S (via) to 74F08 pin 11 (output)
R221 S to 74F08 pin 9 & 10 (inputs)
R221 N to 74F08 pin 8 (output)
Other connections power the 74F08.

Your suggestion regarding HDDriver is a good one - the only reason I haven't done this is because I didn't fancy taking the machine apart to get at the CF card, thinking I could use the NetUSBee to transfer stuff across. I agree that it might be the way forward if the floppy problem is not easily fixable. I am pretty confident the HD works OK.

What is strange is that I was able to copy the HDDriver software from the floppy drive without problems. So it used to work better than it does now...

Yes, that is my water damaged Electron and Plus 1. The Electron is done, the Plus 1 not so much, but I'm working on it...

As for electrons I'm up to about 4 now, plus a spare mainboard :)

Sounds like it isn't heavily modded then.

If it was just the FDD I might suggest it has bad caps or something, but given you have similar issues with the Gotek then I'd suggest something else is wrong.

As for NetUSBee I don't believe the transfer rate is particularly high, which is why I never had one, though I did start building one a long time ago. Has the Falcon been recapped or is it just the PSU?

[jms2]

It's just the PSU. Is it normally thought necessary to do the mainboard as well?

[jms2]

https://joy.sophics.cz/parcp/parcpusb.html

This is what I use for file transfers, not the fastest but 100% reliable.

Interesting, thanks. Well worth remembering as it's useful for a range of machines.
My priority for now though, is to get working the equipment that I have already got.

[jms2]

I have been investigating further and have discovered a possible theory.

I was totally wrong when I previously said I had installed HDDriver. I hadn't - what I actually have installed is ICD Pro v6.5.5. It auto runs on startup and puts up a massive banner so I don't know why I didn't remember that! :lol:

A couple of things I notice about the installation:
1) There are a couple of subfolders, but there's nothing in them. I now appreciate that this is what seems to happen when I copy things from the floppy, so is consistent with other behaviour.
2) When I try to run any of the .PRG utilities, I get TOS error #35. This seems to happen whenever I run any .PRG file from the hard disc, but not from the floppy.

It occurs to me that something has changed since I first started using the machine - ICD Pro is now running all the time! Could it be that this is somehow causing problems? It's been a while since I researched drivers for the CF card, so I can't remember why I didn't go with HDDriver - I'll have to refresh my memory on that.

One other thing - I looked at the floppy cable and I notice that the motherboard end appears to be physically attached rather than plugged onto a header. The plastic case of the plug goes all the way down to the PCB, and if I try to lift it with a sensible level of force, it doesn't move. I assume it's not really permanently attached though!

[rubber_jonnie]

I have been investigating further and have discovered a possible theory.

I was totally wrong when I previously said I had installed HDDriver. I hadn't - what I actually have installed is ICD Pro v6.5.5. It auto runs on startup and puts up a massive banner so I don't know why I didn't remember that! :lol:

FYI ICD Pro won't let you use the drive under Windows.

I assume it's not really permanently attached though!

If it's anything like the ST's, then it's likely to be permanently attached!!! I replace it with a plug where I can on STs.

[jms2]

OK, that's two useful things established. I think I went for ICD pro on the basis that it was "good enough" and also free. It does seem to be Falcon compatible, so I can't see how it might be affecting floppy access, but maybe if my CF card isn't one of the ones which works it could be causing problems...