SviRu Posted March 7 Share Posted March 7 (edited) Hi. I have a stock 1050. Drive is working upon power up. When running 1050 diagnostic it fails on Motor SPEED to low. When reading RPM it is 0. It is 100% PCB not the drive. When turning VR2 there is no difference in speed - voltage is also not changing on the emitter of Q6 (around 10V) / spindle motor. VR2 is working > measured. 1. Is it a dead Q6 or U5? Something else? Thanks for ideas. Edited March 7 by SviRu Quote Link to comment Share on other sites More sharing options...
xrbrevin Posted March 7 Share Posted March 7 might be worth testing the resistance of the trimpot in case it has failed Quote Link to comment Share on other sites More sharing options...
+kheller2 Posted March 7 Share Posted March 7 Can it actually read a disk (dirty head)? 2 Quote Link to comment Share on other sites More sharing options...
Peri Noid Posted March 7 Share Posted March 7 11 minutes ago, kheller2 said: Can it actually read a disk (dirty head)? Agreed, I'd check this first. Speed is checked by reading, if a drive cannot read, it cannot report anything useful. Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted March 7 Share Posted March 7 He may have a two part issue, Q6 Q4 and the chip... and possible head amp... not a whole heck of a lot of information to go on yet. Why do I say this? because he says there is no change in visible speed when adjusting the vr and because it reads zero rpm for a reading. We really don't know what rpm is at play since they was no strobe light speed reported We weren't told if it even makes SIO beeps. We don't know if it responds to SIO commands. We don't know what it's bring up and diagnostic response are. We don't know if it steps the head out and back. Quote Link to comment Share on other sites More sharing options...
SviRu Posted March 7 Author Share Posted March 7 4 minutes ago, _The Doctor__ said: He may have a two part issue, Q6 Q4 and the chip... and possible head amp... not a whole heck of a lot of information to go on yet. Why do I say this? because he says there is no change in visible speed when adjusting the vr and because it reads zero rpm for a reading. We really don't know what rpm is at play since they was no strobe light speed reported We weren't told if it even makes SIO beeps. We don't know if it responds to SIO commands. We don't know what it's bring up and diagnostic response are. We don't know if it steps the head out and back. It takes commands through SIO with diagnostic disk. As mentioned. So it is communicating. It fails on speed test and stepper motor. Than it it spins and spins. Yes head is going up and down so track zero sensor is fine. Also the mechanism is 110% ok. It is the PCB. I have tested with good tested mechanism and the same issue is present. Drive has no info what kind of speed we have. I have measured Voltage at the junction of Q4 and Q6 while adjusting the pot. There is no change in voltage at all. I assume U5 is dead at this point. This is my first suspect. Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted March 8 Share Posted March 8 13 hours ago, SviRu said: I have measured Voltage at the junction of Q4 and Q6 while adjusting the pot. I would check for voltage changes on U5, it may be Q4 at fault in which case you won't see any changes on Q4 or Q6 Quote Link to comment Share on other sites More sharing options...
SviRu Posted March 8 Author Share Posted March 8 11 minutes ago, TGB1718 said: I would check for voltage changes on U5, it may be Q4 at fault in which case you won't see any changes on Q4 or Q6 Thanks. I checked voltages on emitter of Q6> 10.6v - drive spins way to fast. On my working drive it is 7.7V. What voltage would I be looking for on U5 to determine if Q4 is working fine? Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted March 8 Share Posted March 8 16 minutes ago, SviRu said: Thanks. I checked voltages on emitter of Q6> 10.6v - drive spins way to fast. On my working drive it is 7.7V. What voltage would I be looking for on U5 to determine if Q4 is working fine? The service manual says 1.8V Quote Link to comment Share on other sites More sharing options...
SviRu Posted March 8 Author Share Posted March 8 2 hours ago, TGB1718 said: The service manual says 1.8V I will check all the voltages later. I have one thing I do not understand. 1. Is U5 giving feedback to RIOT U7 or U7 pin11 is giving U5 a signal to start the motor? 2. How RPM is calculated? Is it by reading the disc? So there is no real feedback from tacho to anything else than U5? Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted March 8 Share Posted March 8 (edited) 10 minutes ago, SviRu said: 1. Is U5 giving feedback to RIOT U7 or U7 pin11 is giving U5 a signal to start the motor? No feedback, just turn motor on, the signal from U5 controls the speed by biasing the emitter of Q4. I think the speed is checked by reading a sector and timing the next time it reads the sector again Edited March 8 by TGB1718 1 Quote Link to comment Share on other sites More sharing options...
SviRu Posted March 8 Author Share Posted March 8 8 minutes ago, TGB1718 said: No feedback, just turn motor on, the signal from U5 controls the speed by biasing the emitter of Q4. I think the speed is checked by reading a sector and timing the next time it reads the sector again Thanks I thought so. So since the drive spins and stops RIOT is ok. The issue is with Q4 Q6 or U5. Soon I will know Quote Link to comment Share on other sites More sharing options...
SviRu Posted March 8 Author Share Posted March 8 4 hours ago, TGB1718 said: No feedback, just turn motor on, the signal from U5 controls the speed by biasing the emitter of Q4. I think the speed is checked by reading a sector and timing the next time it reads the sector again Drive is fully working now flawlessly. There was a dry joint from U5 pin 4 to Q4. All in all I learned a lot about 1050 Thanks for help! 3 Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted March 8 Share Posted March 8 Result Glad you got it going Quote Link to comment Share on other sites More sharing options...
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