Kryoflux stopped working for two sided disks

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ivandiaz
Posts: 18
Joined: Wed Sep 05, 2018 12:47 pm

Kryoflux stopped working for two sided disks

Post by ivandiaz » Wed Sep 05, 2018 5:54 pm

I bought a Kryoflux recently, and dumped a lot of disks of 5,25", 3,5" and 3" sizes, I am very happy with the results, but yesterday the board started to act up, it now reads only side 0 of dual sided and flippy disks, I have tested with another cable and 3 different drives and the result is the same:

D:\kryoflux>dtc -p -f"p3/p3" -i -g2 -i4 -l8 -dd1
KryoFlux DiskTool Console, v3.00_Win64, uiv.1, Apr 15 2018, 23:44:54
(c) 2009-2018 KryoFlux Products & Services Ltd.
Developed by The Software Preservation Society, www.softpres.org
Licensed for private, non-commercial use only.

00.0 : MFM: OK, trk: 000, sec: 9
00.1 : MFM: OK*, trk: 000, sec: 9, *S
01.0 : MFM: OK, trk: 001, sec: 9
01.1 : MFM: OK*, trk: 001, sec: 9, *S
02.0 : MFM: OK, trk: 002, sec: 9
02.1 : MFM: OK*, trk: 002, sec: 9, *S
03.0 : MFM: OK, trk: 003, sec: 9
03.1 : MFM: OK*, trk: 003, sec: 9, *S
04.0 : MFM: OK, trk: 004, sec: 9
.....

On C64 disks it only works without the -y option, as logically, the data are not reversed on side 0.

I think the problem may be in the board but could you help me with this problem?

ZrX
Posts: 477
Joined: Tue Dec 06, 2011 9:09 pm

Re: Kryoflux stopped working for two sided disks

Post by ZrX » Wed Sep 05, 2018 6:15 pm

If changing cable makes no difference it sounds like the head/side select signal of the board has somehow gone dead.

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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: Kryoflux stopped working for two sided disks

Post by mr.vince » Fri Sep 07, 2018 9:17 am

Ivan, are you able to hook a scope to the board? The side select comes from the SoC and goes through the bus driver (which translates from 3V to 5V).

ivandiaz
Posts: 18
Joined: Wed Sep 05, 2018 12:47 pm

Re: Kryoflux stopped working for two sided disks

Post by ivandiaz » Fri Sep 07, 2018 9:44 am

Hi:
Yes, I didn't did that before because I thought you wouldn't want me to. I used the schematic for E1 in the 3.00 software bundle.

I have a analog crt hameg hm604 60mhz, after connecting it to pin 8 of the 74act244 and running a C64 dump command in the laptop, I could see the line changing between 3,3v and 0v in perfect sync with the program (first only side 1 in the negative realm, then alternating each track). I then tested line 12 (the output directly connected to SIDE1), and it was stuck at 5v. So that confirms that chip as the culprit.

I can replace the chip, but perhaps you prefer me to mail it?

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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: Kryoflux stopped working for two sided disks

Post by mr.vince » Tue Sep 11, 2018 8:02 pm

Might have been static - hot swapping drives is know to cause this from time to time.

The bus driver is a standard component - swapping it locally might be the easiest and cheapest way. But contact me (we've emailed before) if you'd like to send it in for service.

Glad to see the schematics get used for servicing - this is why we included them.

ivandiaz
Posts: 18
Joined: Wed Sep 05, 2018 12:47 pm

Re: Kryoflux stopped working for two sided disks

Post by ivandiaz » Wed Sep 12, 2018 9:45 am

Yes, I will try to replace it, I bought the replacement bus driver already, the zone is a little cramped with all these jumpers, but a SOIC 20 shouldn't be so difficult, you don't use epoxy underfill right?.

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mr.vince
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Re: Kryoflux stopped working for two sided disks

Post by mr.vince » Wed Sep 12, 2018 1:47 pm

Not to my knowledge, no. There's no friction or mechanical force on the ICs, so they should not be glued. However, since it's a contractor producing them, can't say for sure. What I can say is that for the very few units we've ever had to service, there's never been any issue with parts glued.

ivandiaz
Posts: 18
Joined: Wed Sep 05, 2018 12:47 pm

Re: Kryoflux stopped working for two sided disks

Post by ivandiaz » Wed Sep 12, 2018 6:45 pm

The 74xx244 arrived today, and I proceeded to replace it, now it works correctly, I read a DOS formatted dual side disk fine. It was not easy since the jumpers are very close, in fact the write gate one directly touches the chip. In the next revision, I would move them next to the usb. You can see photos from the "surgery" at https://photos.app.goo.gl/NfaiL8WCEUE5tpCp7

ZrX
Posts: 477
Joined: Tue Dec 06, 2011 9:09 pm

Re: Kryoflux stopped working for two sided disks

Post by ZrX » Wed Sep 12, 2018 8:24 pm

That went cleanly. :)

ivandiaz
Posts: 18
Joined: Wed Sep 05, 2018 12:47 pm

Re: Kryoflux stopped working for two sided disks

Post by ivandiaz » Thu Sep 13, 2018 8:12 am

Thanks, but you can see I did slightly melt the jumpers with the hot air and scored the floppy connector with the iron. If someone wants to replicate this, I recommend to desolder the jumper headers first, you will have much more space to work and no risk of melting them.

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