Amstrad 6128: disk is missing after belt change

[kubi]

Hi all,


I'm a nooby on the world of the Nostalgeek. I just found a 6128 last week.
It started well, but as a good old boy, the belt was burst.


So Ive bought a new one, change it with no difficult. I ve cleaned everything with Q-tip. And add some grease on moving part.


But when i started again, i ve always the "disk is missing" message of the death.


So what is the situation:

   
• 12v and 5v reach the disk drive. (verified with multimeter)
• the led of the front panel is softly red
• the led above the disk reader is enlighten ( smby can explain me it is used for?)
• when i type the cat function, nothing is moving: not the stepper, nor the motor. No noise.
• And the message "Disk is missing".
• Ive tried to put a voltage source directly on the motor and i can see it turns.
• Ive tested each pin of the flat ribbon, and everything seems fine.

I think im missing something, but i can't see what i can test more.


Any advice is welcome.


And sorry for my english...

[GUNHED]

You lost the pin of the drive.

[GeoffB17]

On the basis of what you say, the computer may be OK.   But it is not detecting, or recognising the disk, to the point that it says the disk is not there.

What was the state of the old belt.   There may be bits of belt stuck in places they should not, which is interfering.

Have you checked the disk physically?   Does this disk work elsewhere, or has it worked before.   Do you have other disks known to be good that also do not work?

I don't know what the 6128 does, but when you first put the disk in the drive, does anything happen at all, i.e. before you get to entering CAT.

The pin just mentioned is for Write protect.   It should not affect merely reading the disk

Geoff

[Gryzor]

You lost the pin of the drive.

Nope

[Bryce]

If as you say "nothing is moving" and there's "no noise" then the 12V isn't getting to the motor. Check for dry joints on the power socket and the connector that goes to the disk motor and check that you've reconnected all connectors you disconnected to change the belt.

Bryce.

[gerald]

In addition to Bryce advice and according to the drive models there are "fuses" on the 5V and 12V entry that need to be checked.
They are located near the supply connectector and look like transistors. 
EME-156V : Q3 / Q4
EME-157V : Q3

[kubi]

In addition to Bryce advice and according to the drive models there are "fuses" on the 5V and 12V entry that need to be checked.
They are located near the supply connectector and look like transistors. 
EME-156V : Q3 / Q4
EME-157V : Q3

Hi,


Thanks to everyone for your help.


The pin for the write protection is in place.


I will test the fuses, and the joints.
Because as i said in previous post, i can see 5V and 12V at the entry of the disk reader.
So it must come from part of the circuit of the reader... but i don't know where yet.

[kubi]

EME-156V

After verification, my drive is a EME-156
Ican't find nor Q3 or Q4
Do you know where to find a technical plan of Amstrad 6128?


Edit:
Ive removed the new belt to test if the motor start without it, and the answer is NO.
Ive found a Q2 transistor near the motor, and he is ok.

[Bryce]

If it's not the "V" version of the 156, then it doesn't have Q3/4. Try measuring the voltage directly at the motor when you do a "CAT". You should get 12V for a few seconds.

Bryce.

[kubi]

If it's not the "V" version of the 156, then it doesn't have Q3/4. Try measuring the voltage directly at the motor when you do a "CAT". You should get 12V for a few seconds.

Bryce.

This is exactly my problem: ive only 1.27V on my motor, with no change of the voltage during CAT command.


Do you know wich pin(s) i must test on the flat ribbon when i send the Cat command?

[Bryce]

Then either the transistor is bad or you have a dry joint at one of the points I mentioned earlier. A dry joint is more likely.
There is no "CAT" signal, it's a bunch of commands. You can test the MOTORON signal, Pin 8 on the flat cable.

Bryce.

[kubi]

Then either the transistor is bad or you have a dry joint at one of the points I mentioned earlier. A dry joint is more likely.
There is no "CAT" signal, it's a bunch of commands. You can test the MOTORON signal, Pin 8 on the flat cable.

Bryce.

If i follow the order  that i can see in the back of my drive: J1 PIN 8, i have always 0.1V, without modification during CAT command...
So, i imagine that voltage should increase during cat command,isnt'it?

[Bryce]

No. The signal is normally high, ie: when it goes low the motor should turn on.

Bryce.

[kubi]

No. The signal is normally high, ie: when it goes low the motor should turn on.

Bryce.

Ca you correct if I'm wrong:


RED 1 3 5 7 9 .... <-- Ground
RED 2 4 6 8 10 ...


To test the signal Ive just to put my metrics on the pin 8 and in one point of the ground line?
Normally, i must have 5V, and the voltage should fall when i CAT?

[Bryce]

Yes, that's correct.

Bryce.

[kubi]

Ok, There are my measures on idle (no command) on the PIN from the motherboard:


PIN 2 : 5V
PIN 4 : 0.3V
PIN 6 : 0V
PIN 8 : 0.3 -> 0.6 V
PIN 10 :0.3 -> 0.6 V
PIN 12 : 0.3 -> 0.6 V
PIN 14 : 0.06 V
PIN 16 : 0.6 V
PIN 18 : 5 V
PIN 20 : 5 V
PIN 22 : 5 V
PIN 24 : 0.8 -> 1 V
PIN 26: 5V

And i don't know what to conclude with it

[kubi]

Hi all,


A little Up with the last measurments.


Somebody has an idea of a test that can permit to know if the drive is dead or if the problem come from the motherboard?

[Bryce]

You can disconnect the floppy drive and test that the correct pins are going high or low when you enter a command.

Bryce.