A500 Floppy Issues - Page 2

jraclarke · 25 November 2015, 21:20

That's a good point actually. In fact, looking at the "pinion" it looks like there may only be 5 or 6 teeth per rotation.

Interestingly, tonight I tried to use Xcopy to copy from a known working disk in df1 to a blank disk in df0 (the broken drive). If the drive was just misaligned then even the "misaligned" drive would probably read from the copied disk if if was written to by the same drive?

Anyway, no luck on that front, the floppy couldn't be read by df0 and checkdisk didn't like it either.

Thanks,

demolition · 25 November 2015, 21:33

Since it can't read it's own written disks, it could also be the electronics on the drive. I had one drive which could not write disks properly but after replacing the (leaking) capacitors, it worked again. I guess the supply was not stable enough when it would draw current to write the disk.
On some drives, it could maybe also affect reading if the supply had extra noise on it? I would mainly suspect aluminium SMD caps though, not the leaded one I can see on the picture.

jraclarke · 26 November 2015, 01:30

Quote:

Originally Posted by demolition

Since it can't read it's own written disks, it could also be the electronics on the drive. I had one drive which could not write disks properly but after replacing the (leaking) capacitors, it worked again. I guess the supply was not stable enough when it would draw current to write the disk.
On some drives, it could maybe also affect reading if the supply had extra noise on it? I would mainly suspect aluminium SMD caps though, not the leaded one I can see on the picture.

Thanks demolition.

Sounds like it could well be that. I had another look inside the drive tonight (didn't want to take it apart again just yet for the risk of springaggeddon over the floor): following some Googling of things that I don't know (SMD and leaded capacitors), whilst most of them were leaded caps, I spotted one underneath that was SMD (see the badly photographed image - I think it's the blue thing).

A couple of things that I noticed - firstly that it has some white "gunge" around the base, and secondly that it's marked C07. Assuming that the caps were marked sequentially on the PCB (I'm really not an electronics expert as you can tell), then there should be several others amongst the 4 leaded ones that I can see. So it could be just this or a combination of those I cannot see.

My next steps will be:

Get the internal drive out properly,
Check out the state of the caps properly
If needed, learn how to solder and buy a kit.
Attempt a fix, fail, try again.

I will however, keep you posted. Let me know if you think I'm on the wrong track!

demolition · 26 November 2015, 07:35

This is how they usually look:

jraclarke · 26 November 2015, 23:06

Thanks again.

I think I may have found the candidate, C11 - see what you think, I've attached the photo (sorry that's the best quality I could get). It's showing signs of leakage on the top and the -ve side.

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amigasith · 27 November 2015, 09:01

Hi jraclarke, yes this capacitor looks really bad

However, if this cap is already done, chances are quite high that the other electrolytic caps are also about to die.

I just checked, and the Epson SMD-400 has 5 electrolytic caps that are all exactly the same - C08, C09, C10, C11, and C05. They are 10uF if I remember correctly. If the rest of the drive is okay, chances are quite good that it will work again after changing the caps. By doing so, I managed to get one SMD-400 working again.

I have another SMD-400, however, that I could not bring back from the dead just by changing the caps. There is one component that I cannot identify - X0, maybe a crystal - that has leaked very badly and I just don't know what to replace it with. Cheers and good luck

jraclarke · 27 November 2015, 13:23

Thanks Amigasith, I found the old post with your ceramic cap replacement: looked pretty cool. I would be aiming to do the same sort of thing.

Interesting that you say about the other caps as well - having a closer look last night, on a lot of the PCBs contacts there is some form of corrosion (white residue). These coincide with being close to where the caps are placed (though the caps themselves don't show any signs of corrosion). So I'm thinking that they're all due to be replaced.

Out of interest, why is it that the caps on the floppy PCB have lasted less time than the motherboard, were they of a lower quality in general?

Anyway, my plan is to remove and replace the caps - this may take a while as I haven't soldered since school so some practice is required. If it works, it works, if not, then at least I had a go!

I'll let you know how I get on...

Overdoc · 27 November 2015, 15:35

Sounds to me like an alignment issue.
If the drive is out of alignment, then from my experience it will not be able to write to the tracks correctly, so it cannot even read back disks that were written with this drive.

Aligning a 3,5" drive is a real pain, you need to work veeeery precisely!
However, I have successfully done this at least 20 or 30 times, mostly on Chinon FB354 drives. I also use the X-Copy method, which works quite well.

Please first make sure that X-Copy is only checking the lower head. The perfect position is dependent on the track-0 sensor as well as the stepper motor position. You have to fiddle around a bit to find it. Once the drive can read at least some tracks, then the track-0 position is usually ok, and you can try to turn the stepper motor in very small steps between checks.
Only once the lower head is aligned correctly, you can than start with the upper head, which just needs to be positioned correctly on the carriage, exactly over the lower head.

jraclarke · 27 November 2015, 16:15

Thanks Overdoc,

It could well also be an alignment issue, but I think there's more to it than that as both the stepper motor and track-0 sensor are completely fixed. Despite this, running Xcopy on the lower head returns failures and inconsistent results.

No doubt that this info will be valuable though as I will need to align once I see if the caps are causing a problem as well!

jraclarke · 27 November 2015, 23:00

Also, I noticed Amigasith that the thing that I originally thought was a leaking cap, was the X01 object that I think you were referring to. I noticed that this had potentially leaked as well. (it's in a previous pic). Oh well, we'll see...

jraclarke · 07 December 2015, 00:58

The saga continues.

Bought a new Floppy drive and it worked absolutely fine to begin with. But now it's showing exactly the same symptoms as the original drive! I'm guessing it must be one of the chips that's causing the problem, rather than the drive itself.

Is there any chance that the chips could be breaking the drives though? I don't want to break anymore!

jraclarke · 08 January 2016, 13:45

Problem solved (well to some extent).

For anyone that experiences this problem I just replaced the Gary chip with a new one and the new internal floppy drive works!

Strangely though, the old one still doesn't. XCopy fails even on the lower head. I'm going to try having another go at fixing this, now that I can guarantee that everything else works!

James

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25 November 2015, 21:20	#21
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	That's a good point actually. In fact, looking at the "pinion" it looks like there may only be 5 or 6 teeth per rotation. Interestingly, tonight I tried to use Xcopy to copy from a known working disk in df1 to a blank disk in df0 (the broken drive). If the drive was just misaligned then even the "misaligned" drive would probably read from the copied disk if if was written to by the same drive? Anyway, no luck on that front, the floppy couldn't be read by df0 and checkdisk didn't like it either. Thanks,

25 November 2015, 21:33	#22
demolition Unregistered User Join Date: Sep 2012 Location: Copenhagen / DK Age: 43 Posts: 4,190	Since it can't read it's own written disks, it could also be the electronics on the drive. I had one drive which could not write disks properly but after replacing the (leaking) capacitors, it worked again. I guess the supply was not stable enough when it would draw current to write the disk. On some drives, it could maybe also affect reading if the supply had extra noise on it? I would mainly suspect aluminium SMD caps though, not the leaded one I can see on the picture.

26 November 2015, 07:35	#24
demolition Unregistered User Join Date: Sep 2012 Location: Copenhagen / DK Age: 43 Posts: 4,190	This is how they usually look:

26 November 2015, 23:06	#25
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	Thanks again. I think I may have found the candidate, C11 - see what you think, I've attached the photo (sorry that's the best quality I could get). It's showing signs of leakage on the top and the -ve side.

27 November 2015, 09:01	#26
amigasith Registered User Join Date: Jan 2013 Location: Wild South / Germany Age: 48 Posts: 271	Hi jraclarke, yes this capacitor looks really bad However, if this cap is already done, chances are quite high that the other electrolytic caps are also about to die. I just checked, and the Epson SMD-400 has 5 electrolytic caps that are all exactly the same - C08, C09, C10, C11, and C05. They are 10uF if I remember correctly. If the rest of the drive is okay, chances are quite good that it will work again after changing the caps. By doing so, I managed to get one SMD-400 working again. I have another SMD-400, however, that I could not bring back from the dead just by changing the caps. There is one component that I cannot identify - X0, maybe a crystal - that has leaked very badly and I just don't know what to replace it with. Cheers and good luck

27 November 2015, 13:23	#27
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	Thanks Amigasith, I found the old post with your ceramic cap replacement: looked pretty cool. I would be aiming to do the same sort of thing. Interesting that you say about the other caps as well - having a closer look last night, on a lot of the PCBs contacts there is some form of corrosion (white residue). These coincide with being close to where the caps are placed (though the caps themselves don't show any signs of corrosion). So I'm thinking that they're all due to be replaced. Out of interest, why is it that the caps on the floppy PCB have lasted less time than the motherboard, were they of a lower quality in general? Anyway, my plan is to remove and replace the caps - this may take a while as I haven't soldered since school so some practice is required. If it works, it works, if not, then at least I had a go! I'll let you know how I get on...

27 November 2015, 15:35	#28
Overdoc Commodore Collector Join Date: Aug 2001 Location: Austria Age: 53 Posts: 944	Sounds to me like an alignment issue. If the drive is out of alignment, then from my experience it will not be able to write to the tracks correctly, so it cannot even read back disks that were written with this drive. Aligning a 3,5" drive is a real pain, you need to work veeeery precisely! However, I have successfully done this at least 20 or 30 times, mostly on Chinon FB354 drives. I also use the X-Copy method, which works quite well. Please first make sure that X-Copy is only checking the lower head. The perfect position is dependent on the track-0 sensor as well as the stepper motor position. You have to fiddle around a bit to find it. Once the drive can read at least some tracks, then the track-0 position is usually ok, and you can try to turn the stepper motor in very small steps between checks. Only once the lower head is aligned correctly, you can than start with the upper head, which just needs to be positioned correctly on the carriage, exactly over the lower head.

27 November 2015, 16:15	#29
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	Thanks Overdoc, It could well also be an alignment issue, but I think there's more to it than that as both the stepper motor and track-0 sensor are completely fixed. Despite this, running Xcopy on the lower head returns failures and inconsistent results. No doubt that this info will be valuable though as I will need to align once I see if the caps are causing a problem as well!

27 November 2015, 23:00	#30
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	Also, I noticed Amigasith that the thing that I originally thought was a leaking cap, was the X01 object that I think you were referring to. I noticed that this had potentially leaked as well. (it's in a previous pic). Oh well, we'll see...

07 December 2015, 00:58	#31
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	The saga continues. Bought a new Floppy drive and it worked absolutely fine to begin with. But now it's showing exactly the same symptoms as the original drive! I'm guessing it must be one of the chips that's causing the problem, rather than the drive itself. Is there any chance that the chips could be breaking the drives though? I don't want to break anymore!

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

08 January 2016, 13:45	#32
jraclarke Registered User Join Date: Oct 2015 Location: Southampton, UK Age: 40 Posts: 26	Problem solved (well to some extent). For anyone that experiences this problem I just replaced the Gary chip with a new one and the new internal floppy drive works! Strangely though, the old one still doesn't. XCopy fails even on the lower head. I'm going to try having another go at fixing this, now that I can guarantee that everything else works! James