Epson SD-521 DD errors/fail

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Colday
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Epson SD-521 DD errors/fail

Post by Colday » Fri Sep 13, 2019 5:45 pm

Hi guys.

Ok, I now have a very smooth working Beeb (I was having some issues with it faffing about and a dirty screen output, so I cleaned the power terminals on the motherboard with alcohol and it is now sweet, made a hell of a difference) and I have been trying to get the double disk drives I have working.

Ok, so I bought these from eBay and was told that the top drive was not working but that the bottom was.

So I opened them up and was having a look. I had bought some blank disks from Ebay (new Kodak ones) but when I was performing commands (trying to format etc) I was getting 'No Directory' errors. (I managed to free up a stuck motor so now I hope both drives are working ok). I also noted that neither of the heads were moving in the drives.

So I started looking at the ROMS I had in the board and and I found I have a total of 3x DFS ROMS. (ADFS, WE DFS and TurboMMC DFS)

Now I decided to pull some of the bits, so pulled the ADFS out and all of a sudden I get some action from the drives.

Do these ROMS clash? It makes sense to me that they would.

So I removed the TurboMMC ROM and the ADFS rom, leaving the Watford Electronics DDFS ROM in the board. So, now the drives seem to pick up, I can direct the Beeb to look at either drive 0 or 1 and it tries to access whichever one I ask it to, however, I still cannot get the drives to read/write to the disks. (heads still not moving)

I bought a WE utils disk off eBay and it doesn't work for me. Just spins the drive up with no head read/write movement.

So, crux of the matter, I do not know if it is a ROM thing, a Beeb thing or a drive thing, and as far as I can tell I have no simple way of working out which is causing the issue. So...

Call for help, does anyone have a working external drive (single or dual) that is definitely working that I can either borrow or buy (at a reasonable price) so that I can bottom out the issues I have? (I am happy to buy for info and am not looking for charity)

Please feel free to send ideas for testing, I plan to start videoing my tests and will make them available on my Discord channel (address to follow)

Thanks for all your help in advance (as I know you are all awesome)

Col.
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Kazzie
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Re: Epson SD-521 DD errors/fail

Post by Kazzie » Fri Sep 13, 2019 6:45 pm

I'm sure we can get some sense out of these drives for you.

Removing all but one of the disk ROMs is a good idea. It should be the case that only the one in the highest priority socket is activated, but better safe than sorry!

I presume (given that you've un-stuck the motor on one) that you've opened the drives up. With the drive off, are you able to push the head assembly out toward the edge? When you power the drive and attempt to *CAT a disk, the drive should step the head assembly back to the center of the disk (track 0).

There's a simple disk formatting BASIC program here. If you run that with a blank floppy in the drive, and it fails, it should print out an error code from the floppy disk controller, which will indicate to us what the Beeb thinks the problem is.

What type of FDC do you have installed in IC78? is it an 8271 chip, or a 1770 on a daughterboard?

Finally, for reference, what sort of testing equipment do you have access to? (Multimeter, logic probe, oscilloscope, etc.)
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
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Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Fri Sep 13, 2019 8:46 pm

Ok, cool.

This is good stuff...

Yes, I have opened the drives up (both) both spin freely now. As for the heads moving...

Nope, Neither move at all.

I will do some further testing without ROMS etc (I put them back in as usual as I wanted to play Frak ;0))

Which would be the best one to leave in?

I'll post some pics..

As for FDC in IC78 I believe it is the daughterboard one, but I will post some pics to the discord in a bit...

Testing equipment I only have 2x multimeters at present, looking to find a reasonably cheap oscilloscope soon though.

Discord link... https://discord.gg/EXSBYx

I've popped a few pics on the above discord link.

Discord for those of you that do not know is great for quick posting of pics and videos as they can be sent direct from a phone etc.

I created the Wiki for my CPC experiments but I have to say the Beeb has my heart now. We had one in school before I got the CPC at home. Loved Frak!
Last edited by Colday on Fri Sep 13, 2019 8:52 pm, edited 1 time in total.
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Fri Sep 13, 2019 8:53 pm

If you want pics of specific things or areas on the motherboard, including videos of me typing command with their results on the Beeb, let me know.
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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hoglet
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Re: Epson SD-521 DD errors/fail

Post by hoglet » Fri Sep 13, 2019 9:06 pm

Colday wrote:
Fri Sep 13, 2019 8:46 pm
I've popped a few pics on the above discord link.
The account creation step will, I think, put many people off.

I think you'll get more of a response if you posted photos locally here.

Also, they will still be viewable in 5 years time, so the thread will still make sense.

Dave
Last edited by hoglet on Fri Sep 13, 2019 9:08 pm, edited 1 time in total.

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KenLowe
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Re: Epson SD-521 DD errors/fail

Post by KenLowe » Fri Sep 13, 2019 9:11 pm

Indeed. I've just spent the last 5 mins trying to log in to an old account. I've given up!

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Fri Sep 13, 2019 9:20 pm

I do apologise Gents (and potential Ladies)

I thought that link would give you auto access via the web.

Apparently my bad.

What's the best way of posting pics/vids via the forum?

I can set up whatever accounts are necessary via external agencies if I must.

(I like discord as it is instant and allows posting directly from a Smartphone, I do recommend using it and using the time to set up a quick account if necessary)
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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KenLowe
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Re: Epson SD-521 DD errors/fail

Post by KenLowe » Fri Sep 13, 2019 10:11 pm

Eventually regained access to my discord account and was able to see your photos. So, it looks like you've got a Watford Electronics 1770 based controller. I'm not familiar with the WE DDFS that you've got installed in the ROM expansion board, but I presume it's just a 1770 based DFS for use with the WE 1770 controller. This will be the ROM that you need to use to communicate with the 1770 controller and the disk drives. The TurboSPI ROM, which is also plugged into the ROM expansion board, will be used to read / write disk images to an SD card that plugs into the user port. Suggest you remove this ROM when testing the disk drives. At the very least, you should install it in a lower numbered ROM bank than the WE DDFS to ensure the WE DDFS gets priority.

Edit: Here's a copy of the photos...
Attachments
image0.jpg
image1.jpg
image2.jpg
Last edited by KenLowe on Fri Sep 13, 2019 10:15 pm, edited 1 time in total.

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1024MAK
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Re: Epson SD-521 DD errors/fail

Post by 1024MAK » Fri Sep 13, 2019 11:39 pm

Colday wrote:
Fri Sep 13, 2019 9:20 pm
What's the best way of posting pics/vids via the forum?
Below the text editor box are two tabs, the left hand one gives ‘Options’, the one just to the right is ‘Attachments’, so click on ‘Attachments’. Then click on the ‘Add files’ button. What happens next depends on your system, but it should allow you to access a file selector, or on mobile devices, select photos (and maybe other files).

Then make your selection(s)...

Wait while they upload, then add a comment if you wish (recommended). If you want the file or photo to be in the main body of your post, move the text cursor to where you want the file or photo, then click ‘Place inline’.

If you want the file or photo to be at the bottom of your post, don’t click ‘Place inline’!

Now finish editing your post in the normal way. I do recommend that you use the ‘Preview’ button to confirm that your post comes out how you expect it.

With photos and files, to prevent the forum from eating up lots of server hard disk space, please don’t post large files unless absolutely necessary. The forum has compression and size reduction enabled for jpeg images.

If there is a genuine need to post a high resolution detailed photo, please pack it in a zip file before uploading.

I hope this helps ;-)

Mark
Last edited by 1024MAK on Fri Sep 13, 2019 11:41 pm, edited 1 time in total.

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hoglet
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Re: Epson SD-521 DD errors/fail

Post by hoglet » Sat Sep 14, 2019 6:51 am

Colday wrote:
Fri Sep 13, 2019 5:45 pm
Please feel free to send ideas for testing
Can you tell us what version of Watford DDFS you have? Use *HELP for this.

The Watford DDB3 board requires version 1.54T or later I believe. It's also compatible with the Acorn 1770 DFS, which is more standard.

What error do you get when you *CAT a disk?

Have you tried formatting a blank disk?

The commands for formatting are:
- *ENABLE
- *FORM80 0

One possible hardware fault is tarnished connections on the floppy drive connector on the Beeb. This can usually be fixed easily by plugging/unplugging the cable 10-20 times.

Dave
Last edited by hoglet on Sat Sep 14, 2019 6:58 am, edited 4 times in total.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 7:34 am

Ah this is great stuff.

I'd not tried the *ENABLE command prior to the format and I had tried formatting with *FORM40 0 as I figured that would likely be more universally accepted by the machines.

When I had the ROMS removed, leaving just 1, if I formatted the disk would start up and whir, but the heads remained static.

If I left the WE daughterboard (middle of the motherboard) in, any disk commands gave me 'No directory' as a response.

I shall drink this coffee and head up to start testing again. Will take a laptop up with me so I can get the photo's on here for you all.
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Kazzie
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Re: Epson SD-521 DD errors/fail

Post by Kazzie » Sat Sep 14, 2019 7:52 am

Hi,

One thing missing from your photo album is any pictures of the floppy drive. :wink:

I'm going to work on the assumption that the photos on this side are a good match for your drive, for the time being.

This drive has an older style of stepper motor, being that big black lump of a cube in the corner of the drive. It's electrically simple: applying a current on different pairs of wires rotates the axle (due to the coils and magnets inside the lump). I can't recall how it's linked up mechanically to the head assembly, I've only handled one drive with this type of stepper, and that wasn't the bit at fault.

It's possible that the manner in which the stepper motor is connected to the head assembly (and the gearing involved) is stopping you from being able to move the head assembly along its rails.
SD521-stepper-motor.png
Close-up of stepper motor of SD-521. Stepper axle is circled, mounting screws indicated with arrows
Try rolling the stepper motor's axle (circled) gently with a finger. That may be enough to get the heads moving a bit. Once you've moved them a short distance away from their current position, you can connect the drive up again, and see if the heads move back to track 0 when you try to *CAT the drive.

If you can't get any movement from the axle, one possibility would be to disconnect the stepper motor from the chassis, and then see if the head assembly will move. Going from memory and the pictures I've got to hand, it appears to be affixed by two screws I've pointed out with blue arrows. If you're not sure about this, though, don't rush into it: some more photos of the area where the stepper motor connects to the assembly would be useful.

Note that there are some parts of a floppy drive you shouldn't disassemble if you can avoid it: removing the head assembly or track 0 sensors can leave you with a fiddly job of realigning them again when you reassemble the drive (otherwise you won't be able to read anyone else's discs, and nobody will be able to read yours!). The stepper motor isn't one of these crucial components, however.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
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Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 8:09 am

Stepper motor seems fine, head moves freely.

I've disconnected one of the drives so am simply operating on a single now (just to make it simpler).

I shall remove all the DFS ROMS shortly.

Which would you recommend I leave in?

I shall take a couple of pics of the drives in a bit as well.
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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KenLowe
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Re: Epson SD-521 DD errors/fail

Post by KenLowe » Sat Sep 14, 2019 8:27 am

Colday wrote:
Sat Sep 14, 2019 8:09 am
I shall remove all the DFS ROMS shortly.

Which would you recommend I leave in?
You need to leave in the Watford DDFS ROM. You also need to provide version number of this ROM as previously requested by Hoglet (using *HELP).

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 8:29 am

Yup, no problem.

Shall I remove the ADFS daughterboard in the middle of the motherboard?
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 8:32 am

ROMS installed:

Advanced DFS 1,30

Watford Electronics DDFS 1.54T

OS 1.20

I had most success last evening when I removed the ADFS card but am happy to be guided by you all for this testing...
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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hoglet
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Re: Epson SD-521 DD errors/fail

Post by hoglet » Sat Sep 14, 2019 8:50 am

You definitely need to leave the Watford Electronics DDB3 Card in place. This contains the 1770 disc controller used by both Watford DDFS and Acorn ADFS. Without this there is no way the disk interface will function.

Remove the ADFS and Turbo MMC ROMS.

Insert a blank floppy disk into drive 0 and do:
- *ENABLE
- *FORM80 0

Take a screen shot of the exact error message.

Then insert a blank floppy disk into drive 1 and do:
- *ENABLE
- *FORM80 1

Again, take a screen shot of the exact error message.

If the system appears to hang, be patient. Wait at least a minute before giving up!

Dave
Last edited by hoglet on Sat Sep 14, 2019 8:52 am, edited 3 times in total.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 8:52 am

I dont have a specific ADFS ROM to remove..
There is the TurboMMC ROM (already removed) and the WE DDFS ROM in the RAM board.

To remove the ADFS I need to remove the DDB3 card
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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hoglet
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Re: Epson SD-521 DD errors/fail

Post by hoglet » Sat Sep 14, 2019 9:02 am

Colday wrote:
Sat Sep 14, 2019 8:52 am
To remove the ADFS I need to remove the DDB3 card
Again, don't remove the DDB3 card, it's the only disk controller in ther system!

ADFS will be one of the devices on the ROM board.

Can you post a close up photo of the ROM board, so I can read the ROM part numbers.

One of those ROMs will be ADFS 1.30 - probably the unlabelled masked ROM that is (c) Acorn - but I can't quite read the part number.

Dave

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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 9:04 am

IMG_3391.jpg
IMG_3392.jpg
IMG_3393.jpg
IMG_3394.jpg
So, I have removed the ROM's from the boards, and the screenshot is what I get
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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hoglet
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Re: Epson SD-521 DD errors/fail

Post by hoglet » Sat Sep 14, 2019 9:14 am

Colday wrote:
Sat Sep 14, 2019 9:04 am
So, I have removed the ROM's from the boards, and the screenshot is what I get
The unlabelled ROM in IC8 in the ROM board is almost certainly ADFS.

(Edit: The Acorn part number 0201274-02 is definitely ADFS 1.30)

Remove this, and reinsert the Watford DDFS ROM.

Then try formatting a disc as outlined earlier, take photos of the errors, and post these.

Dave
Last edited by hoglet on Sat Sep 14, 2019 9:18 am, edited 3 times in total.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 9:24 am

Ok, did as suggested. The commands now work
IMG_3395.jpg
The drive spins up but the heads don't move.

It seems to do this until I hit [Escape]
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 9:27 am

I have changed the drives over and went down to

*form40

It now seems to be formatting the disk!!
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Colday
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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 9:27 am

I shall try the *form80 with a different disk once it has finished!
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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hoglet
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Re: Epson SD-521 DD errors/fail

Post by hoglet » Sat Sep 14, 2019 9:36 am

That looks promising....

Is there any manufacturer name / model number on either of the the disk drives, or on the case?

Edit: Ah, I see from earlier in the thread that it's a SD-521. Let me google that....

Another command to try if you have formatted a disc successfully is *VERIFY <drive number>

And also *CAT <drive number>

Dave
Last edited by hoglet on Sat Sep 14, 2019 9:41 am, edited 2 times in total.

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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 9:39 am

Make and model are in the title but..

Epson SD-521
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

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Re: Epson SD-521 DD errors/fail

Post by jgharston » Sat Sep 14, 2019 9:40 am

Colday wrote:
Sat Sep 14, 2019 9:04 am

Code: Select all

BBC Computer 32K
Acorn ADFS   <-------
BASIC
>*ENABLE
No directory
>
So, I have removed the ROMs from the boards, and the screenshot is what I get
It would help if you selected DISK before issuing DISK commands.

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.25
(C) Copyright J.G.Harston 1989,2005-2015
>_

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Re: Epson SD-521 DD errors/fail

Post by hoglet » Sat Sep 14, 2019 9:44 am

It seems the SD-521 is possibly only a 40 track drive, so be careful of using *FORM80.

If the drive head seems to be trying to step beyond the end of the disk surface, hit BREAK quickly!

Edit: Yes, it's refered to as a 360K DSDD 48 TPI, which will only be 40 tracks. So stick to *FORM40

I'm off out now for a bit....

Dave
Last edited by hoglet on Sat Sep 14, 2019 9:49 am, edited 2 times in total.

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Re: Epson SD-521 DD errors/fail

Post by Colday » Sat Sep 14, 2019 10:26 am

Ok.

So the first disk I tried just wouldn't format, so I tried a new disk again and hey presto, it formatted fine (40 track).

I tried the 2nd drive but the heads deffo don't move, but now I have a known working drive I can compare values etc to see what has failed. I suspect it could be the stepper motor or the driver for that.

Awesome help again guys.

I now apparently have a spare ADFS chip. I may plop that back in and see if I can work around it now I know the drive is good.
BBC B's... I had five but was stupid when young and skipped them. (Yeah I know)
Now have an Issue 7 B with a few issues I'm working through.
Also have a dual disk drive (only one works at the moment) but no disks.
Retro computers.... money pits.

Kazzie
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Re: Epson SD-521 DD errors/fail

Post by Kazzie » Sat Sep 14, 2019 11:30 am

Good to see you've got one drive working. =D>

A nice thing about having two identical drives is that you can use one as a reference when troubleshooting the other. :)

(Am I right in concluding that with the faulty drive, trying to rotate the stepper motor axle by hand didn't move it at all?)
Last edited by Kazzie on Sat Sep 14, 2019 11:31 am, edited 1 time in total.
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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