The Sinclair QL Forum

On my 2 QL’S ITA (New) I assist on a strange problem.

The First QL all ok in reading and format all kind of cartridges from the start, in the second QL the MDV1 unit at the start seems won’t format all that MDV2 unit formats…very strange…I change the unit with other from my friend and…all return working ok.

Now on my first QL are 2/3 days that the MDV1 unit stops format anything…in reading all ok but on format not…why?

Is it possible that after many readings or writing the MD unit stops working well?

Or is the Eletric Motor that change his speed?

I’ve just changed on it the Capstan roller 1 time (buyed from Rich)

Did you know that problem?

The preservation for QL is very expensive…and unstable…

Thanks for all that you can think or do for me.

Best regards.

P.S.: some friends have suggested me:

a) I have seen that problem, but maybe the microdrive motor is not working at the correct speed.

b) It's usually down to the rollers - make sure they're good. Also make sure the metal spring is pushing the cartridge against the roller properly.
This is a VERY common problem

Simon,

did the drive work properly after you installed the new roller? There's a critical measurement between the lower roller edge and the casing - if you push the roller too far down, the rubber may come in contact with the casing and the motor is slowed down.
Check the service manual for instructions.

Tobias

Well when was changed worked very well.

Now after...hundreds of md's restored (in less that 1,5 months) it become a little slow and will not format well.

I see the same in other drive (NEW) but also after changhing the roller he continue working bad.

You suggest to buy some new rollers from Rich?

I see you have purchased some more rollers - they should last longer than that - although I know you have been working your way through a lot of temperamental microdrive cartridges (don't forget to clean the residue from the tape heads and the roller). You can also try turning the roller upside down (as it is the top half which gets worn).

The other thing to check is that the small heat shield is in place around the ULA on mdv1 - without that the ULA can get temperamental due to the heat...

RWAP wrote:I see you have purchased some more rollers - they should last longer than that - although I know you have been working your way through a lot of temperamental microdrive cartridges (don't forget to clean the residue from the tape heads and the roller). You can also try turning the roller upside down (as it is the top half which gets worn).

The other thing to check is that the small heat shield is in place around the ULA on mdv1 - without that the ULA can get temperamental due to the heat...

Yes Rich but just that I have to re-open my QL I prefer to change it with new

And I've also to buy another one (3 in total) for change the one of my Speccy MD unit too ^_^

Thanks for the suggestions.

Ranma_Simon wrote:

RWAP wrote:I see you have purchased some more rollers - they should last longer than that - although I know you have been working your way through a lot of temperamental microdrive cartridges (don't forget to clean the residue from the tape heads and the roller). You can also try turning the roller upside down (as it is the top half which gets worn).

The other thing to check is that the small heat shield is in place around the ULA on mdv1 - without that the ULA can get temperamental due to the heat...

Yes Rich but just that I have to re-open my QL I prefer to change it with new

And I've also to buy another one (3 in total) for change the one of my Speccy MD unit too ^_^

Thanks for the suggestions.

Naturally If I need a ULA / shield and a new voltage regulator please send me all that I need.

Thanks.

RWAP wrote:The other thing to check is that the small heat shield is in place around the ULA on mdv1 - without that the ULA can get temperamental due to the heat...

Hi Rich,

According to the QL Service Manual, the shielding on Microdrive 1 ULA is RF Shielding, not sure where from, as Microdrive 2 ULA, is not fitted with shielding.

Maybe there is some sort of interference from TV signal generation in the modular.

The QL Service Manual upto Issue 5/6 doe snot give any comments to indicate the purpose of the shielding. Some maybe it is a bit of both, i.e. Heat & RF

It is an RF shield that shields the QL from the ULA. Without it, microdrive activity can affect the video image. Some video images could also impact operation of the MDV.

Hi Dave,

Why is there not a RF Shield on MDV2?

It is 3x further from the video area, so 1/8th the interference.