Help - Question for someone with plus machine and external Floppy Drive

[tjohnson]

Hi all,


A quick question to anyone who has a plus machine with an external floppy drive.  Is the drive motor enabled whenever the computer is switched off?


The reason I ask is I have just connected my 3.5" floppy drive to my plus machine and when the machine is switched off the drive constantly spins, but when switched on it behaves normally.  Connected to my normal CPC6128 it acts normally in both scenarios.


So my question, is this normal behaviour for a plus model?


Thanks Trevor

[GUNHED]

Get it OFF immediately!


You probably haven't used the B-drive adaptor for the Plus. On the cable it's moved one position to the side. Sorry can't say it better in Englisch.


You MUST NOT plug a CPC floppy to the Plus, the contacts are switched. See port documentation!

[Bryce]

His cable is correct, it has the wires shifted and he has a different cable for the Classic CPC. He used the diagram I made on the Wiki. I think this may be normal as the ASIC NMOTORON signal may have a path to ground when the CPC isn't powered. But I don't have a cable or floppy to test this at the moment, so he is asking others that have this setup.


Bryce. 

[dragon]

I remember the mine do the same when i use the 3,5 fdd.

[GUNHED]

My drives stay silent.

[Bryce]

My drives stay silent.

Is your drive an external 3.5in drive with seperate power supply and connected to the floppy port of a CPC+?

Bryce.

[Maniac]

I don’t recall my external 3.5” drive motor being on when my 6128plus is off.

[tjohnson]

Sounds inconclusive at the moment!

Sent from my E5823 using Tapatalk

[ComSoft6128]

6128+ with external 3.5" drive. Powered by external PSU. No activity when not in use.

Cheers,

Peter

[GUNHED]

Is your drive an external 3.5in drive with seperate power supply and connected to the floppy port of a CPC+?

Bryce.

Yes. Exactly. Same works for the 5.25" being connected.

[tjohnson]

I did some more testing using the drive connected internally worth another cable i have made, 26p to 34p and it does exactly the same, so it looks like the cable is not an issue.  So im assuming something funny about the drive, will get another drive to test, or this is by design on the plus machine.

Sent from my E5823 using Tapatalk

[Bryce]

If you have a multimeter, it would be interesting to know what the resistance between the NMOTORON signal and GND is, when the machine is turned off.

Bryce.

[tjohnson]

Measure it on the pin on the cable to ground?  Do you know which pin it is, although i can probably find it on the service manual or cpcwiki site.  Thanks Trevor

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[Bryce]

Yes, measure the resistance between pin 8 and 9 on the socket at the back of the CPC. If it's low resistance or a short, then the CPC is causing the drive to spin. If it's open circuit, the drive is doing it of its own accord.

Bryce.