• Please review our updated Terms and Rules here

Cbm dual drive 3040 disk - two red lights

Excellent!

So, you now need to apply the temporary link to the same point on the other disk drive's motor speed controller PCB (left hand side drive, drive #1).

Do you think you can do that on your own?

The two tests that you will need to perform before powering up are:

1. Measure the resistance between UB2 pin 7 and 14 again - you should read approximately 115 Ohms.

2. Follow the ORANGE and BLACK leads back from the motor speed controller PCB that you have modified and test at the disk drive connector for 0 Ohms between the two points where the ORANGE and BLACK cables are.

The resistor is now R1 instead of R4 - but I don't think you need to perform these tests again (unless you really want to of course).

Let me know when you are done and you are happy BEFORE we apply power.

Dave
 
daver2 said:
Excellent!

So, you now need to apply the temporary link to the same point on the other disk drive's motor speed controller PCB (left hand side drive, drive #1).

Do you think you can do that on your own?

The two tests that you will need to perform before powering up are:

1. Measure the resistance between UB2 pin 7 and 14 again - you should read approximately 115 Ohms.

2. Follow the ORANGE and BLACK leads back from the motor speed controller PCB that you have modified and test at the disk drive connector for 0 Ohms between the two points where the ORANGE and BLACK cables are.

The resistor is now R1 instead of R4 - but I don't think you need to perform these tests again (unless you really want to of course).

Let me know when you are done and you are happy BEFORE we apply power.

Dave
Click to expand...
Ok thanks but before, i will have to remove the card from the drive to be able to solder the wire :(
 
I am desperate!!
I applied the wire but when i turn on, drive 1 s' motor doesn't spinning!!! :(
UB2 pin 7 to 14 always 115 Ohm
 
You went one step further than I said...

Did you double check that you had 0 Ohms between the two pins of the black disk drive connector that has the BLACK and ORANGE wires from the motor speed controller PCB?

I was going to say NOT to be desperate if it didn't work!

If you remember, this is the drive that didn't spin last time you tested it. So it would only spin now if you had made a mistake last time. As it is - we are confident that the drive motor itself is probably OK (you measured some resistance between the RED and BLUE wires going to the motor) - so I am suspecting an electronics fault on the speed controller PCB that we have to track down now. In order to do this - you will need the link fitting that we have just fitted!

We are further along on our journey - just not quite there yet.

Dave
 
With the power on to the disk drive unit can you measure the voltage on the three pins of the power transistor that is located on the speed controller PCB please:

1664737287874.png

To do this:

1. Put the black lead of your multimeter onto 0V/GND.
2. Set the multimeter to a range to read 12V DC full scale.
3. Use the red lead of your multimeter to probe each of the three pins in turn on the transistor - and note down the voltage reading.

Lets use the nomenclature of LEFT, CENTRE and RIGHT pin as we look at the picture in this post shall we.

This is with your little temporary link fitted of course.

Can you also measure and report all of the DC voltages around the speed controller IC on the board also. Again, with the black probe of the multimeter always on 0V/GND and using the red probe on each pin in turn. Please note which pin of the IC has which voltage reading please. All the voltages should be in the range 0V to +12V DC.

1664737556416.png

I am going to be around tomorrow (Monday) morning - but then I am on a business trip for 3 days. I will have access to the internet, but only via my phone.

Dave
 
daver2 said:
With the power on to the disk drive unit can you measure the voltage on the three pins of the power transistor that is located on the speed controller PCB please:

View attachment 1246877

To do this:

1. Put the black lead of your multimeter onto 0V/GND.
2. Set the multimeter to a range to read 12V DC full scale.
3. Use the red lead of your multimeter to probe each of the three pins in turn on the transistor - and note down the voltage reading.

Lets use the nomenclature of LEFT, CENTRE and RIGHT pin as we look at the picture in this post shall we.

This is with your little temporary link fitted of course.

Can you also measure and report all of the DC voltages around the speed controller IC on the board also. Again, with the black probe of the multimeter always on 0V/GND and using the red probe on each pin in turn. Please note which pin of the IC has which voltage reading please. All the voltages should be in the range 0V to +12V DC.

View attachment 1246879

I am going to be around tomorrow (Monday) morning - but then I am on a business trip for 3 days. I will have access to the internet, but only via my phone.

Dave
Click to expand...
Thanks so much Dave! I ll do these tests tomorrow after job!
Have a good night and nice trip!
 
daver2 said:
1. Put the black lead of your multimeter onto 0V/GND.
2. Set the multimeter to a range to read 12V DC full scale.
3. Use the red lead of your multimeter to probe each of the three pins in turn on the transistor - and note down the voltage reading.

Lets use the nomenclature of LEFT, CENTRE and RIGHT pin as we look at the picture in this post shall we.
Click to expand...
LEFT: 12,1 V
CENTRE: 0 V
RIGHT: 11,8 V
 
daver2 said:
Can you also measure and report all of the DC voltages around the speed controller IC on the board also.
Click to expand...
1: 0 V
2: 4,9 V
3: 0 V
4: 2 V
5: 0
6: 0
7: 0
8: 12 V
9: 7,3 V
10: 0
11: 0
12: 0
13: 0
14: 0
 
Great work Dave & Desperado.

It looks like the frequency to voltage converter IC, on its pin 8, is instructing the output transistor Q1 to be in the off condition. To get the output transistor to conduct well the voltage across its base to emitter junction (connections) base would have to be more than about 0.7v, and it is only about 0.3V on Desperado's meter checking. So the IC's pin 8 has to go lower than 12V to activate the motor. Because the transistor Q1 is switched off, its collector voltage (center connection) assumes zero volts because of the low resistance of the motor load to ground.

The next likely move might be to get the pdf data sheet for the IC to work out why the IC's pin 8 is sitting at 12V even though the Motor on input has been grounded (assuming that input is active low-needs checking), though the data sheet might have been posted already and I missed it.

Interesting though that the "motor ON" input is coupled via a diode with the output of the line being on the diode cathode, kind of suggesting it might be an active high control line, but it could still be an active high to stop the motor (and therefore a low to start it), but then one might have imagined the line would have been labelled "motor off". But that would be clear when the IC's data sheet was inspected.
 
Last edited:
We tested the other controller in the same way, and the signal really is active low.

I am on a business trip at the moment, but I hate using my phone virtual keyboard...

I have some ideas for when I get back on Thursday, but if anyone else wants to jump in...

Dave
 
Hugo,

Had a little chance to have a look before breakfast, and I agree with your assessment.

I would propose (for a quick test) to link out pins 5 and 8 of the F to V IC. This should be the emitter and collector of the driver transistor in the IC.

If I am correct, and the fault is the IC (or ahead of it), the motor should start to spin.

Do you concur?

Dave
 
daver2 said:
Hugo,

Had a little chance to have a look before breakfast, and I agree with your assessment.

I would propose (for a quick test) to link out pins 5 and 8 of the F to V IC. This should be the emitter and collector of the driver transistor in the IC.

If I am correct, and the fault is the IC (or ahead of it), the motor should start to spin.

Do you concur?

Dave
Click to expand...

I'm not sure what the part number of that control IC is ? It should be stamped on the IC body or maybe somewhere in the manual.

If we had that, we could look at the internal IC architecture and try to figure out what it is supposed to be doing, with the Motor on signal polarity.

Clearly though, its output stage is supposed to pull pin 8 below the 12V rail to activate the motor.
 
daver2 said:
Hugo,

Had a little chance to have a look before breakfast, and I agree with your assessment.

I would propose (for a quick test) to link out pins 5 and 8 of the F to V IC. This should be the emitter and collector of the driver transistor in the IC.

If I am correct, and the fault is the IC (or ahead of it), the motor should start to spin.

Do you concur?

Dave
Click to expand...
So need i solded a wire between pin 5 and 8 of this lm2907?
 
You must log in or register to reply here.
Back
Top