The Sinclair QL Forum

Hi guys, today I finally had some microdrive cassettes to test on my Sinclair QL. However, I noticed that at start-up, only MDV1_ has the LED light up, while MDV2_ has no LED light and you don't hear the engine running (for testing) during start-up. I did some reading tests with MDV1_ and it works correctly, while for MDV2_, as I thought, no motor is running.

I then swapped drives, putting MDV1_ on MDV2_'s slot and vice versa. I have determined that there is power only on the left slot, so I can be pretty sure that there is no power on the right one. Could someone of you give me some suggestions on what I could measure, and possibly a diagram of the voltages in the two connectors where the drive sockets go?

Robbizz wrote: Wed Jun 14, 2023 10:40 pmI then swapped drives, putting MDV1_ on MDV2_'s slot and vice versa. I have determined that there is power only on the left slot, so I can be pretty sure that there is no power on the right one. Could someone of you give me some suggestions on what I could measure, and possibly a diagram of the voltages in the two connectors where the drive sockets go?

That's easy, go to Dilwyn's site. At this site you can download the official Sinclair Guide for repairing the QL (sorry don't know the name, but it's not the Technical Guide [that's the official guide for the QL software]). Unfortunately I don't know the URL (this site is HUGE), but I know it's there(!), because I posess the original manual (in printed form) and have seen it there.

Regards

Peter

Note that mdv2_ will not start up on boot in any case, when it stays silent, that's normal.

It should, however, react to commands.

tofro wrote: Thu Jun 15, 2023 5:20 am Note that mdv2_ will not start up on boot in any case, when it stays silent, that's normal.

It should, however, react to commands.

So is the fact that the LED doesn't turn on when starting MDV2_ also normal?

ql_freak wrote: Thu Jun 15, 2023 1:17 am

Robbizz wrote: Wed Jun 14, 2023 10:40 pmI then swapped drives, putting MDV1_ on MDV2_'s slot and vice versa. I have determined that there is power only on the left slot, so I can be pretty sure that there is no power on the right one. Could someone of you give me some suggestions on what I could measure, and possibly a diagram of the voltages in the two connectors where the drive sockets go?

That's easy, go to Dilwyn's site. At this site you can download the official Sinclair Guide for repairing the QL (sorry don't know the name, but it's not the Technical Guide [that's the official guide for the QL software]). Unfortunately I don't know the URL (this site is HUGE), but I know it's there(!), because I posess the original manual (in printed form) and have seen it there.

Regards

Peter

Service manual

I believe the drives get their '9v' feed from the same input, so if the problem moves with the drive - it's likely to be an issue on the drive PCB - these have their own on board 5V regulator - you could check the pins either side of the se regulators - you should see 9v on one leg, and 5V on the other. Keep the black lead of your meter on a 0v feed - the metal can for the TV modulator is handy...

Robbizz wrote: Thu Jun 15, 2023 7:34 am

tofro wrote: Thu Jun 15, 2023 5:20 am Note that mdv2_ will not start up on boot in any case, when it stays silent, that's normal.

It should, however, react to commands.

So is the fact that the LED doesn't turn on when starting MDV2_ also normal?

If the motor of MDV2 spins, then LED should come on. If it does not, then it might be a faulty LED, or a problem with the wires from the LED's where they plug into the main board. It's not a very good connector, and the wires can easily get pulled out/put in the wrong holes if someone's had the top of the computer off.

ql_freak wrote: Thu Jun 15, 2023 1:17 am That's easy, go to Dilwyn's site. At this site you can download the official Sinclair Guide for repairing the QL (sorry don't know the name, but it's not the Technical Guide [that's the official guide for the QL software]). Unfortunately I don't know the URL (this site is HUGE), but I know it's there(!), because I posess the original manual (in printed form) and have seen it there.
Regards
Peter

The QL Service Manual is available as an eBook in a few formats, including PDF, here: https://dilwyn.theqlforum.com/docs/ebooks/index.html

There's also an online HTML version on Urs's site at https://www.sinclairql.net/srv/index.html