Drive A: disc missing

[khaz]

This is maddening. I replaced the drive belt, put the pin back in place, and the computer keeps telling me this, whether or not I put a disc in it. I don't know what my problem is, if the disc isn't detected or if the whole drive isn't recognised or something. The LED shines though, so at least it's getting some power. Any idea what to check?

[GeoffB17]

Does the disk arrear to be spinning?   Can you hear the stepper motor doing anything.   Is the data cable connected the right way around?   Maybe a break in the cable?   I assume this partic drive was working OK before the belt went.


Sometimes, it's not JUST a matter of replacing the belt.   If the belt was totally destroyed, there could be bits/residue to be cleaned.


Geoff

[khaz]

The drive doesn't spin. It gives the error message at the same speed whether the drive is connected or not. There is no activity at all, except for the shining LED.

The drive used to work, until I had to change the belt. When I was done with the belt, the drive worked properly for a couple of minutes, until it didn't.

[gerald]

The drive doesn't spin. It gives the error message at the same speed whether the drive is connected or not. There is no activity at all, except for the shining LED.

The drive used to work, until I had to change the belt. When I was done with the belt, the drive worked properly for a couple of minutes, until it didn't.

Check that the belt is still in place 

[khaz]

Check that the belt is still in place 

I will, but shouldn't I at least hear/see the motor spinning?

[gerald]

I will, but shouldn't I at least hear/see the motor spinning?

The drive motor is realy quite, most of the noise come from the disk itself

[khaz]

The belt is still in place. Not moving.

[khaz]

I checked the ribbon cable: flawless connection between the motherboard and the drive board.

[gerald]

Is it within a 6128 ?
Can you check that the 12V is present at the drive power connector ?
In  a 6128, the 12V to the drive is switched on by 2 transistors when the 5V is present. These may have failed.

[GeoffB17]

Oooh...


Sounds rather like my problem, previously documented, when the stepper motor went.


Except in my case I believe that the disk was spinning.


If your disk is NOT spinning, and the belt is not moving, I'd ask if the pully that should be driving the belt is turning.   Maybe cannot see?


Best to try to run things with the drive OUT of the box, and out of it's metal covers, so you can see what's happening.   The motor will spin the pully, which should move the band, which should spin the larger disk which clamps to the disk centre.


If the pully isn't spinning, then the motor isn't working.  Check if it's getting power.   Remember the drive gets 12v for the motors, and 5v for the electronics, so the lights may be ok but the motor not.


Geoff

[Kris]

SOunds like if you forget to reconnect the 12V for the spinning motor...

[khaz]

It's back in its box for tonight, I'll have a go at it tomorrow and check the voltages. I'm not a fan of working on a live machine, I'm always afraid of frying something.

I only checked for continuity today, and all four power wires were connected up to their socket. I haven't checked all the traces though.

Regarding the motor power, shouldn't there be a difference in timing for the error message to appear? As in, it would take slightly longer to check for a disc as opposed to checking for the drive?

I don't even have a spare working drive to completely rule out a failing motherboard. My HxC works very nicely though, except it shows up on both drives and HxCManager hangs after displaying my root folder. I don't know if it's related. I do my internal drive tests with the HxC unplugged, of course.

[Bryce]

Most likely the 12V are missing. Either the PSU isn't supplying anything or there's a problem on the mainboard.

Bryce.

[khaz]

Well damn it, now the whole thing doesn't turn on any more.

I've had trouble powering it on lately, with random garbage showing up onscreen, but I always managed to get it working after power cycling it a couple of times. It was also usually fine for the rest of the day too. Now, flicking the switch does nothing, with an occasional flash from the power LED. The monitor does give me +5V, as I can use it to power the HxC.

Gerald mentioned failing transistors, maybe my troubles with the disc drive and this power thing are part of the same problem? I didn't even know transistors could fail. To be honest I don't know where to start testing things.

[gerald]

Well damn it, now the whole thing doesn't turn on any more.

I've had trouble powering it on lately, with random garbage showing up onscreen, but I always managed to get it working after power cycling it a couple of times. It was also usually fine for the rest of the day too. Now, flicking the switch does nothing, with an occasional flash from the power LED. The monitor does give me +5V, as I can use it to power the HxC.

If the power led flash, that mean your power supply is likely failing. Checking the 5V with no CPC connected will not tell you much as it can just drop when loaded.
Do you have any alternative power supply to use ?

Gerald mentioned failing transistors, maybe my troubles with the disc drive and this power thing are part of the same problem? I didn't even know transistors could fail. To be honest I don't know where to start testing things.

1- try with an other 5V supply
2- check 5V voltage with CPC on

[khaz]

Do you have any alternative power supply to use ?

Not yet. I've ordered a bunch of cables to have the CPC connected to a telly, but they will take their sweet time to arrive.

Checking the 5V with no CPC connected will not tell you much as it can just drop when loaded.

I'm currently using this kit to connect the HxC to the CPC, and even now when the computer doesn't turn on any more, the HxC gets a steady stream of current.
The CPC LED flashes randomly.
Amstrad Spectrum 3 Kit Ribbon Cable and Power Cable for 3 5" Drive or HXC Emu |

[gerald]

Not yet. I've ordered a bunch of cables to have the CPC connected to a telly, but they will take their sweet time to arrive.

I'm currently using this kit to connect the HxC to the CPC, and even now when the computer doesn't turn on any more, the HxC gets a steady stream of current.
The CPC LED flashes randomly.
Amstrad Spectrum 3 Kit Ribbon Cable and Power Cable for 3 5" Drive or HXC Emu |

Two possibilities :
1 - the power connector has a bad contact. Have you tried powering the CPC directly from the screen (ie, remove all HXC related stuff)
2 - The CPC power switch need a cleanup. To confirm this, just short the 2 pins where it connects. If this is the problem, you will have to open the swich for cleaning it.

[khaz]

Two possibilities :
1 - the power connector has a bad contact. Have you tried powering the CPC directly from the screen (ie, remove all HXC related stuff)
2 - The CPC power switch need a cleanup. To confirm this, just short the 2 pins where it connects. If this is the problem, you will have to open the swich for cleaning it.

Well, I wiggled the switch a bit and the computer just powered on again. So it's definitely the switch that has a problem for +5V. I'll have to clean / repair / change it though as it's quite unreliable now. 1 was the first thing I tried, but it didn't change a thing.

Does anyone have a part number for a CPC 6128 power switch? Or a reputable (ebay) seller?

Still can't make the drive work, still waiting on an alternate +12V source to come in the post.

[Bryce]

It will be difficult to find a replacement, however, they are very easy to open and clean and should work for many years to come.

Bryce.

[khaz]

I finally received the new power cables! The good news is: it totally was missing 12V. The disc drive works perfectly fine with this new power source.

The bad news is: the new power source for +5V doesn't work. It reads 5.09V on the multimetre, it can power the HxC fine, but the CPC refuses to turn on. The +5V from the CTM still work, so at least I can still use the CPC it.

[khaz]

Well that didn't last long.

There is something really weird going on. it worked fine twice, then it stopped working. Again. The new Power cable delivers its 12V correctly. I don't know what is happening.

[edit] And I think the CTM killed my multimeter. I was trying to measure if the computer was receiving 12V, one cable was close to the screen and static electricity went through it

[Bryce]

Was it a cheap meter? The expensive ones should have enough protection to survive a discharge.

Bryce.

[khaz]

Probably, yes. It says it's fused, and it keeps displaying the same digits regardless of what I'm measuring.

I've isolated part of my problem, I think. I replaced the power switch with a jumper and now I have no problem turning the CPC on and using the disc drive. The switch prevents me completely from using the +5V from the cable.

But only when both +5V and +12V come from the power cable. Any other combination make the drive fail:

Code Select Expand


CTM    | Power cable |
5V/12V |     0       |   drive off
5V     |   12V       |   drive off
12V    |    5V       |   drive off
0      | 5V/12V      |      OK!


I've looked briefly at the switch to clean it, but how do you even open it?

[Bryce]

Mixing the voltages as you have done in rows 2 and 3 of your table probably aren't working because you haven't tied the grounds together (assuming the CTM is actually outputing something). However, seeing as Row 1 doesn't work either would indicate that somethings not right in the CTM.

The switch is actually quite easy to open, you just need to bend back the for metal tabs on the back, just be careful not to loose the contents when you open it!

Bryce.