how to use an oscilloscope to measure drive transistors in spindle drive.

[landslide1]

can anyone talk me through measureing the wave forms of the drive transistors in spindle drives?
my drive is a06b-6059-h003 with a a16b-1100-0200 top board.
I don't know if the S5 jumper is applicable to my board.

the next problem is i'm unsure of where to probe. is it b1-U0 with the oscilloscope probe on B1 and the earth on U0?
I can't see wave forms but i'm probably not testing correctly.







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[freakycnc]

Be very careful here! there may be 300VDC which will blow the probes off your scope if you slip!!! S5 will not let current flow through the power section. I would measure from B1 - U0 through B2R - N2 with a voltmeter first. This will tell you if you have an open base drive XSTR. If you have 300VDC then check the fuses on the top board. Then check the same terminal on CN5 or CN4 - CN6 depending on the size of the drive looking for the small voltage described in the drive MNT manual. If it's 0.0 - .8 V the drivers for that XSTR is no good. 1.0 - 1.5 should be OK.

freakycnc

[landslide1]

Be very careful here! there may be 300VDC which will blow the probes off your scope if you slip!!! S5 will not let current flow through the power section. I would measure from B1 - U0 through B2R - N2 with a voltmeter first. This will tell you if you have an open base drive XSTR. If you have 300VDC then check the fuses on the top board. Then check the same terminal on CN5 or CN4 - CN6 depending on the size of the drive looking for the small voltage described in the drive MNT manual. If it's 0.0 - .8 V the drivers for that XSTR is no good. 1.0 - 1.5 should be OK.

freakycnc

Thanks for the advice!

my initial voltage testing across the test points was high not low. Most were about 2V and one was 1.1V. The one that had the 1.1V and looked good was found to have a short across the transistor. when I removed the transistor I found it tested ok but the small glass diodes behind it were shorted. I'll re-test using a volt meter now that the diodes have been replaced.

[landslide1]

I tested again and the voltage across the testpoints is -1.7V for the first 3 then -2V for the rest. the only one with a clear fail is the one where I replaced the transistor and the diodes @ -0.6v.
all fuses are ok but one did blow with the igbt and I have changed it.

[landslide1]

I got a clear procedure from another drive and was able to see the wave forms. it isn't like the manual states. the wave form is a varying duty cycle that goes from 100% and down.

I had a working circuit and found the bad components using a diode tester. replaced them and the wave form looked like the others so I hooked up the motor and it runs!

I still don't know if the test voltages being high is a big problem as all my drives have about 2.7V across them.