Micro drive continuously spinning

[Gbrigden]

Hello,

Just got a QL after I sold mine many moons ago. So it great to find this forum and learn again.

However i do have a problem with my QL. When I power it up, both micro drive lights come on, the motors in both spin, and do not stop.

I am not able to load anything etc, they just keep spinning
I can F1, type in a program and it run fine, all the time the drives are spinning.

Any thoughts in what I can try and do to fix this?

Many thanks
Gary

[martyn_hill]

Hi Gary and welcome!

You'll find quite a few posts relating to flaky MDVs around here, each with diverse recommendations depending upon the specific symptoms, but I'll start by saying that, in my experience, constantly spinning drives is indicative of faulty MDV ULAs which are less than convenient to replace (though doable.)

It is the MDV ULA that is responsible for recognising the 'drive-enable' command from the QL's 'peripheral' ULA (ZX8302) and enabling the power circuit to each drive and, when faulty, the MDV ULA can sometimes leave it's own power circuit enabled continuously.

There are other possible causes that are easier to fix, but it takes (your) time troubleshooting what is likely to be the ULA after-all. I believe that replacement MDV ULAs are still available (from RWAP Services), but to de-solder the existing ICs and fit the replacement involves a 'surgical' operation on the drive, which may be marginal in any case.

Don't however let me put you off pursuing the troubleshooting process - just be aware that it may well soak-up your time when replacement optinos such as the brilliant QL-SD Card interface may be time and money better spent. Your call entirely...

If you do want to pursue some troubleshooting, then:
1. Download the QL Service Manual and a decent QL schematic from Dilwyn Jones' excellent 'QL Homepage': http://www.dilwyn.me.uk/docs/index.html
2. Try invoking each drive with a simple 'DIR 'mdvN_' and observe whether the spinning stops or changes in some way
3. Focus your attention in the first instance on the two transistors that power each drive (TR6 & TR4 for MDV#1, TR7 & TR5 for #2)
4. It is also possible that the ZX8302 is faulty - much easier to replace, but given the symptoms, I doubt this IC is at fault.

Good luck!

[Gbrigden]

Hi,
Many thanks for the quick response.

I am keep to look at the QL-Sd drive option and the Floppy Emulator too or the vDrive if I can get hold of one.

I will look at some commands around the drives, my dir mdv1_ says not found ans dir mdv2_ will just whirl until I take the cartridge out and tell me not found.

I guess I will have to dig out the screwdriver and start taking the QL apart and see what I can do.

May be i should just focus on the SD option after all

Thanks again.

[Gbrigden]

Hi,
The ULA you speak off, is that on the board behind the drive, one each? Or is it on the motherboard itself?
If I was to buy a replacement board or drive perhaps?

Also its both drives that are spinning too if that makes a difference?

Thanks again

[martyn_hill]

Hi Gary

The ULA in question is soldered direct to the 'head-board' of each MDV unit. The units come complete, with head-board semi-permanently fixed to the chassis - whole units do come up for re-sale from time to time - condition varies, however.

Given that both units spin continuously, I suspect both ULAs (not uncommon - I purchased a pair of units of unknown condition only to find that both ULAs were fired, with each spinning like you observe with yours - careful, painful replacement of one of the ULA (so far) restored correct behaviour.

It's worth exploring those transistors first (easy enough to de-solder and replace cheaply), but without too high expectations.

When you DIR'd each drive, did either spinning change in any way, or did both just continue spinning regardless?

[bwinkel67]

I will look at some commands around the drives, my dir mdv1_ says not found ans dir mdv2_ will just whirl until I take the cartridge out and tell me not found.

So when you do a dir mdv2_, you say that the drive just whirls until you take the cartridge out. In your first post you said it continuously whirls. So does either drive ever stop with anything you do (other than turning the computer off)?

[Gbrigden]

Hi,
Neither of the drives stop. From the moment I power on, until I switch the QL off the motors are rotating.
I did open up the unit tonight to see what was going on, and on both motors they are constant turning. Dir and cat do nothing. I have attempted a format yet though.
Thanks

[stevepoole]

Hi folks,

Perhaps the rubber rollers have ridden up the drive shafts ?

Peer into the microcartidge slots, and if there is a gap between the rollers, take a screwdriver and gently prize the top rollers down.

That cured the same problem I had with my first JM QL !

Then again, there may be some other cause ...

Regards,

Steve.

[Gbrigden]

Thanks I'll look to do that in the morning.

[Gbrigden]

Morning.
With the case apart I can see the rollers are where they are meant to be.
I'm going to take the drives out and have a look around, there isn't much to look at but will remove dust and clean heads etc and see if I can dig out the volt meter to start troubleshooting.
I have located some drive ULA chips online so I may have to get myself a soldering iron too by the looks of it.

Thanks again.