Convert JU257 floppy for Amiga, HELP!!

[redrumloa]

Actually I want to use it with a C= 1581 drive, but that requires converting it the same way as to an Amiga drive.

HERE is the board.

I am using THIS guide. It appears my drive has a different board than what is described. Also I can't seem to open the IFF file, maybe it is corrupt? If you can view the image, please convert the IFF to GIF or JPG? I'd appreciate it.

How to change this drive to DS0 instead of DS1? I can swap pin 2 and 34 on the cable if need be, but drive select seems to be the issue..

HELP!  :-?

[redrumloa]

 :bump:

[rkauer]

redrumloa wrote:
Actually I want to use it with a C= 1581 drive, but that requires converting it the same way as to an Amiga drive.

HERE is the board.

I am using THIS guide. It appears my drive has a different board than what is described. Also I can't seem to open the IFF file, maybe it is corrupt? If you can view the image, please convert the IFF to GIF or JPG? I'd appreciate it.

How to change this drive to DS0 instead of DS1? I can swap pin 2 and 34 on the cable if need be, but drive select seems to be the issue..

HELP!  :-?

 If you are using an external case, the drive must be set as DS1, anyway. For use it as DS0 (and you are unable to find the right jumper), maybe there is a time to use the very ugly cable torsion instead. Simply open the floppy cable connector and twist the pins 10 and 12 (11 is GND, so it don't matter).

[banzai]

Looking at your picture...

It seems the PCB was designed to have switches that would allow... well, switching... the drive to another configuration. It is most likely that Matsushita (Panasonic) decided to save the money on switches and just jumper them at the factory. So...

sw1 = switches RDY and DCHNG lines
sw2 = unknown (just IN and OUT labels) wp or density?
sw3 = Drive Select (D0/D1)
sw4 = unknown (just IN and OUT labels) wp or density?
sw5 = unknown (just PC and SE labels) pc/mac se 800K?
sw6 = unknown (just MS and MO labels) motor sense?

It looks like they hard-wired the pads at switch 3, just below pins 9-10 of the 34-pin connector. In fact, I can make out what seems to be a jumper bridging behind the index pin holes for the switch. You may be able to unsolder the jumpers and install a switch pulled from a non-working floppy (if you have one).

banzai

P.S. I use this site to check the drive info.

[Jope]

Ok, everyone. Stop speculating please.

For the 1581 the drive must be DS0, also for most Amiga external drives the drive must be DS0.

Redrumloa, modify your drive according to:
http://jope.fi/drives/ju257a606p/

There are two smd short circuit blocks that need to be moved and I've put red squares around them. My picture is how it should look after your soldering work.

No cable swap needed, use a straight 34pin cable.

Tested to work with Amigas and the 1581. Don't be alarmed, the drive LED will stay on always with the 1581, just pay attention to your floppy cable orientation. It is marked on both ends.

The drive should burp the stepper motor when you switch it on, if not, your cable is probably the wrong way around or still set at DS1.

[redrumloa]

Awesome info everyone, thanks!

@Jope
Perfect, I should have no problem now. My 128T will be getting an internal 1581 :-D Thanks for the effort!!

[redrumloa]

No luck, I'm stumped. Drive light stays on like expected, the motor bumps when turned on, but trying to load anything you just get file not found error and the power light flashes immediately.

Have you tried this mod with JiffyDOS?

[redrumloa]

@jope

Can you show me a picture of CN6 and CN7?

[Jope]

Works fine with Jiffydos.

Head 0 goes to the rear connector (CN6), head 1 goes to the one closer to the spindle (CN7).

You can't read the CN6/CN7 markings on the drives I have when you're putting them together, the drive's aluminium chassis obscures the text on the silkscreen. :-)

[mrmkl]

Which version of JU257 drive are you going to use?

I think some of them will behave badly both in Amiga and in 1581, atleast with 1581 with WD1772 (contra WD1770)

The reason I think is track to track stepping times not being sufficient for some of the JU257 models.

[Jope]

What kind of behaviour have you been experiencing?

I have done 20 ju257a606p conversions and all of them worked in an Amiga. I haven't tried nearly all of them in a 1581, but the ones I did also worked.

I do realise that 20 is a laughably small number in comparison  to the amount of these drives floating around in the world. :-)

[mrmkl]

I have made a note about one JU-257A427P rev. F.
I think the rw-head does not reach the correct track every time.
I also recall seeing a screenshot of Catweasel configuration utility, where head step pulses were adjusted for some drive, I think it was JU-257-something

[redrumloa]

mrmkl wrote:
Which version of JU257 drive are you going to use?

JU-257A606P

I think some of them will behave badly both in Amiga and in 1581, atleast with 1581 with WD1772 (contra WD1770)

I don't have any WD chip in my 1581, which spot is the WD supposed to be in? U3 or U4?

[redrumloa]

Jope wrote:
What kind of behaviour have you been experiencing?

I type 'load "$",9' and hit enter, the drive power light immediately starts flashing in error and I get "?file not found error".

I type 'load "*",9' and hit enter, I get no drive activity but on screen pause, after about a ~7 seconds, the drive power light starts flashing in error and I get "?file not found error".

[redrumloa]

Umm.. now the 1581 is doing the same thing with the original Chinon drive.. Sigh.. When things go wrong they go wrong.. I hope I still have that 1581 service manual..

-Edit-
Fixed, working again with original Chinon drive.