Another 3.5" FDD question...

[00WReX]

Hi All,

I have been using external 3.5" FDD's for a long time and they work great.
I have a small batch of about 6 FDD's, all common models that you can find modding info for on the net.

Anyway, I have a 6128 that has had a drive problem (original 3") for a while and decided to fit my first internal 3.5" FDD.
I fitted it all up with an absolute minimum of case mods (just a list bit of inside work with the dremmel), and I could still fit the 3" back no problem as no mounting points for that were chopped.

Also the drive I used (Panasonic JU-257A605P) was easily modded for the "Rdy" signal. DS0 & DS 1 has a switch, so very nice.
Wired up as per the standard instructions from the 26 pin to 34 pin connector.

The same as how Bryce described the HxC cable here...
Adaptor Cable for Internal HxC

The drive works perfectly, including getting the "disc missing" and responds to the CPM "remove disc" messages. So basically it works exactly as the 3" should.

Read, Write, Format, even using WriteDSK works no problem.

But here's the thing that has thrown me, and at the minute cannot think of a reason why.
Trying to run an external 3.5" FDD on this machine does not function.
If I disconnect the internal drive connector it's fine.
It appears to be shorting something as the external drive LED comes on as soon as power is applied and buzzing from the drive is heard. Flipped the cable but no better.

This is with drives and cables that all work normally if the internal drive is disconnected.
It was late last night when I tested it then work early next morning, so not much time to think about it.
I'm sure I'm missing something really simple, but cannot think of it as yet.
Will have to consult the 26 & 34 pin descriptions after work.

If somebody can point me in the right direction it would be much appreciated.

Cheers,
Shane

[Bryce]

How is the external FDD connected? Does it have any features on the cable such as a side-switch, ABBA or anything else? Is it set as DS0 or DS1?
What about your powersupply, can it supply enough juice for both drives at the same time?

Bryce.

[00WReX]

Internal drive is set to DS0 external DS1.
External drive is powered by a separate 2 amp supply (not powering anything else).
Side switch, Drive A/B select and Rdy all done via jumpers on the cable (so can be removed, and were during testing).

Basically like this...
Guide on how to connect a 3.5" drive to a CPC6128/664 - CPCWiki

Cheers,
Shane

[Bryce]

Try setting the external drive to DS0.

Bryce.

[00WReX]

Moving the external drive to DS0 gives a constant "disc missing".

Decided to try a couple of things I thought I'd done last night...but maybe I had not.

External drive back to DS1.
Typing |B then cat gives strange results.

Basically the cat gives a mess of a directory listing and strange free space values...one disc even gave a screen of jumbled directory contents then cleared the screen and gave the remaining mess of a listing in mode 0.

A blank disk gave "716k free".

This is all with an external 3.5" disk set to DS1 and the Rdy jumper set.
Nothing else.

Tried 3 different 3.5" drives and all gave the same result with the same disk.
But, if I make the external drive, drive A...then it works.
But the internal drive does not.

Mmm, all seems a bit messy to me for something that should be so simple.
I'm actually not really worried about having an external drive permanently connected, It's now more a matter of getting it working because I would like to see what the issue is.

Just wondering how others have done it (3.5" internal & 3.5" external connected at the same time, and working...such as disc to disc copying) ?

Cheers,
Shane

[Bryce]

I have a similar setup, but the drives have been modded to give the ready signal only when required and both are set to DS0. I don't have a side switch installed. The cable I use is made exactly like this: http://www.cpcwiki.eu/index.php/File:Floppy_Cable.png

Bryce.

[00WReX]

Thanks Bryce.

I have a separate cable for the edge connector & centronics connector.
Both with the configuration as per your diagram.

My cables also have an extra Floppy connector inline to allow temporary jumpering.
Such as shorting 33/34 for Rdy, 31/32 for head/side select, 11/12 for primary drive select...etc

Have not had an issue in the past, only now with the 3.5 setup internally (and this appears to be doing everything perfectly, including all the motor control and LED operation...dull when not in use and bright when disc accessing etc).

Anyway, I'll have another look later on when i get a moment.


Cheers,
Shane

[Cholo]

Im pretty sure youll need to have the external drive set as DS0 to use with your 6128 .. as if you have it set as DS1 (secondary) itll start looking for another drive on the cable and as there isnt one it wont work. At least all the drives (and HxC) ive used externally has been used as the one and only "primary" drive on the cable.

One error that happens quite often when using the "homemade floppycable" (you linked to) is that people forget to turn the primary drive pins (11/12) to "off" position after poweroff. And if you forget to unconnect the drives will behave "odd" when you turn power on next time.

The right way to use the cable is:
1. turn on 6128
2. flick switch to "primary" (connect pins) and the internal and external drives will "swap around".
3. turn off 6128
4. turn "primary" switch to off (not connected).

Thankfully there is no troubles with either the Ready signal or the side connection .. but the "primary" one is the one that really can mess up things. Just a guess  (its quite a common issue).

[00WReX]

Moving the external drive to DS0 gives a constant "disc missing".

Decided to try a couple of things I thought I'd done last night...but maybe I had not.

External drive back to DS1.
Typing |B then cat gives strange results.

Basically the cat gives a mess of a directory listing and strange free space values...one disc even gave a screen of jumbled directory contents then cleared the screen and gave the remaining mess of a listing in mode 0.

A blank disk gave "716k free".

This is all with an external 3.5" disk set to DS1 and the Rdy jumper set.
Nothing else.

Tried 3 different 3.5" drives and all gave the same result with the same disk.
But, if I make the external drive, drive A...then it works.
But the internal drive does not.

Mmm, all seems a bit messy to me for something that should be so simple.
I'm actually not really worried about having an external drive permanently connected, It's now more a matter of getting it working because I would like to see what the issue is.

Just wondering how others have done it (3.5" internal & 3.5" external connected at the same time, and working...such as disc to disc copying) ?

Cheers,
Shane

I know this was a while ago, but I thought I'd posted up the outcome of this (obviously not  )...it took me a couple of days from when I first posted to realise what was happening.
This is one of those moments when you just have to shake your head...
The follow up is for anyone else that may fall for this 

The issue I was experiencing was caused by me having a ROM board connected with Parados on it.

As I'm sure experienced Parados users are aware...by default, drive A is set for normal Amsdos (40 tracks per side - single sided) & drive B is set for 80 tracks per side - double sided.
So when I was putting an Amsdos disk in B it was giving the strange results. 

[attachimg=1]

Cheers,
Shane