another 3.5 floppy drive topic, oh no ! (new pics !)

[jpx13]

Hello dear forumers !

After successfully fixing my CPC 464 (Again thanks to Bryce !), and playing a while with my new toy, I thought of trying the 6128 to enjoy the "fast" disk experience 

I purchased a cheap 6128 that was working, but without the 3" drive... What a joke for the "disk experience"...

I already knew it would be a 3.5" mod, and had 3 PC spare drives, and the right cable with 5.1/4 connector.

I hooked a sony MF920 first, without modding it, and using the jumper wires method on one of the free connectors of the cable. It worked at first try ! 

I was happy, but there was still the problem of the "ready signal" to be fully happy and have disckit3 working correctly.

I tried different mods on my sony drive to provide a proper "ready signal", but none worked, and I ended creating a "half fake" signal with the HD switch. That did the trick and disckit was now working.

All this to come to my question, thanks if you read all this story !!!

I now installed my drive inside my CPC, changing the 26 pin connector for a 34 one, wiring an AB switch to pin 32/31 and wiring together 12 and 11.

It works flawlessly, but my CPC keeps saying me I have 2 drives hooked, and not only one. It is not a real problem, I can use it like this, but I'd rather have it working as it should.

Another point is that I can't hook a second drive to the external connector (with jumper wire on 33/34 to fake the ready signal), my CPC keeps telling me "read fail".

Thank you for your help, I believe it could be related to the DS0/DS1 configuration of the drives but perhaps I 'm wrong.

JP

[gerald]

wiring together 12 and 11

By doing this you make the drive 1 always selected, and if your 3 1/2 drive is configured to be drive 1, then it's always selected, even when the FDC select drive 0.
You have two possibilities :
- make the drive use sel0 (ie get the selection signal from pin 10) : prefered. You should find either a jumper or a smd resistor to move
- modify the cable to put sel0 on pin 12.

Can you post a picture of your drive PCB (there are many different sony MF920)

[jpx13]

Hello, gerald !

I won't be able to post an actual picture of my drive because it is now mounted inside my cpc, but if I understand what you explain, it is a matter of changing the resistor from sel1 to sel 0 and disconnecting the wire between 12 and 11 ?

From the tread : http://www.cpcwiki.eu/forum/amstrad-cpc-hardware/how-to-modify-a-sony-mpf-920-to-provide-a-ready-signal/20/

[attach=2]

In the picture posted by Bryce, it is not exactly the same as mine, but there is the resistor jumper sel 0 /sel1 like on mine. Can I change the resistor without making the "ready" mod or would it interfere ?

There was another tread on the forum about this drive, and I remember that it was explained that there are at least two different controler chip for this drive, and the mod doesn't work for both. What I remember is that mine had the bad version, and thus coulldn't be modified with this method (for the ready signal). That's why I used the HD switch to sense the disk in the drive...

JP

[gerald]

it is a matter of changing the resistor from sel1 to sel 0 and disconnecting the wire between 12 and 11 ?

Yes. You can even ignore the resistor and just make a solder bridge if it's easier for you (it's a 0 ohm resistor)

What I remember is that mine had the bad version, and thus coulldn't be modified with this method (for the ready signal). That's why I used the HD switch to sense the disk in the drive...

How did you connect the switch ? between 34 and 33 ?
Ideally a connection between 34 and the selection signal (where the resistor is) thru a diode (anode on ready side) would be better. The ready should only be active when the drive is selected.
something like :
ready(pin 34) -- switch -- anode / cathode -- drive sel (pin 10)

[jpx13]

OK, I will try to move the jumper between sel 1 and sel 0.

For the HD switch, I just wired the 34 to the pin of the switch that is'nt connected to ground (and cut the trace at pin 34). So when a DD disc is inserted (or a HD one with tape on the hole), the pin 34 goes to ground (as it is when 33 and 34 are tied together).

What kind of diode should I use ? I have a bunch of 1n400x, but are they suitable ?

Again thank you Gerald !

JP

[Bryce]

1N400x are recitifier diodes, they will work, but a 1N4148 (small signal diode) would be the normal diode to use in a case like this.

Bryce.

[jpx13]

Hello,

OK for the diode, I bought them some time ago for some arduino projects to protect my relays or other stuff like that...

I opened my 6128 one more time to modify the drive, and again, with  your help, I managed to get the mod done !

I changed the jumper position, on my drive, it wasn't obvious because there were no "sel1" or "sel0" labels, but following the trace on the PCB to pin 10 and 12, I found the 000 resistor. The labels were J30 and J31, so I changed from J31 to J30, and that did the trick. I have now a working drive, which led is dimly lit when there is no activity, and bright on disk activity ! I hooked my second drive with the external wire, with no 12/11 jumper, because this one is on "sel1", and I have 2 working drives !

While the drive was opened, I changed my wire from pin 34/HD-switch to the disc sensing switch and jumper wired the HD switch. Now, when I put a HD disc inside, i is recognized as a DD without obstruding the HD hole.

Again a big thx to Gerald and Bryce, helpfull as usual !

JP

[jpx13]

Hello !

As an update, I thought i should share what i've just done for my second drive. I have the chance to own a 3D printer so I designed a case to fit the external drive, and it now sits aboce the internal one. The pictures that follow should be self explanatory. I apologize for the mess on my desk, but there are currently 3 computers on a small desk, plus a lot of stuff !!

If someone is interrested by the STL files, I can upload them or send by mail, but as you will see, it's a tight fit at the back of the case, so I don't know if another drive would fit !

External lenght is 155 mm, and 116 wide.

JP

[rpalmer]

jpx13,

Very well done with the case.   

How long did it take to create the external box?
Did you modify the external drive to supply the /READY signal?
Is the internal drive the same manufacturer as the external one? How was that connected to the internal interface?

Also, why not use the 3D printer to make a internal plate for above the internal drive to fill in the space?

rpalmer

[Audronic]

Hello !

As an update, I thought i should share what i've just done for my second drive. I have the chance to own a 3D printer so I designed a case to fit the external drive, and it now sits aboce the internal one.
If someone is interrested by the STL files, I can upload them or send by mail, but as you will see, it's a tight fit at the back of the case, so I don't know if another drive would fit !
External lenght is 155 mm, and 116 wide.
JP

@jpx13


Well done.
I also would like to know what modifications were done to the ALPS DF354H181F Floppy drive.
and also get a copy of the STL Files for the case.
Excellent


Thanks    Ray

[jpx13]

Very well done with the case.   

Thank you 

How long did it take to create the external box?

Designing it took me about 30 minutes, printing both parts about 8 hours or so... 3D printing is fantastic but a bit slow...

Did you modify the external drive to supply the /READY signal?

Yes, I used the "disc inserted" switch to provide the ready signal

Is the internal drive the same manufacturer as the external one? How was that connected to the internal interface?

No, I used the drives that where lying around in my "old computer parts storage" and I found 3 drives from different manufacturers... The external one is an ALPS branded one.

Also, why not use the 3D printer to make a internal plate for above the internal drive to fill in the space?

rpalmer

That is the next thing on my Todo list 

JP

[jpx13]

@jpx13


Well done.
I also would like to know what modifications were done to the ALPS DF354H181F Floppy drive.
and also get a copy of the STL Files for the case.
Excellent


Thanks    Ray

Hello Ray,

I did the same sort of mod as on my Sony MF920E: I used the "Disc inserted" switch to provide a ready signal, and shorted the HD switch to fool the drive and use HD or DD floppy without having to close the HD hole.

I didn't took a picture of the PCB when the drive was opened, but the signals to use are both on the white ribon on the top left of the PCB(34 pin connector facing you). IIRC, the ready signal should be the third whire from the left, and the HD switch the fourth from the right. I suggest anyone that wants to mod the same drive to test this with a multimeter, as I did, because I am not sure about the position of the wires.

I attached the two STLs in this post. Of course they are totally free for anyone's use or modifying !

JP