How to save two Mitsubishi M2896 drive (spindle motor smoked!)
hilpert at cs.ubc.ca
Tue Mar 3 16:49:05 CST 2015
> On 2015-Mar-03, at 11:00 AM, Enrico Lazzerini wrote:
>> Well, on the zener i measured 12,45V. So it is a 12V I think. Not 15V as I
>> previous supposed. It power the pins as I written so :
>> About powers:
>> LB1612 pin 19 datasheet says 8-14VDC
>> TC1642P pin 16 datasheet says 5-9.5VDC
>> C358C pin 8 datasheet says until +32vdc
>> I could try to substitute the zener with a 7808 ic 1W.
>> This could keep all is not warm and protect. RIGHT?
> 8V of a 7808 may be low/marginal for the 8.5V min specified in the LB1620
> datasheet (at least in the Sanyo one I'm looking at).
> You could add a diode or two in series with the GND leg of the 7808 to raise
> the voltage to around 8.6V (1 diode) or 9.2V (2 diodes).
> (cathode to GND, ordinary 1N400x for example).=
On 2015-Mar-03, at 2:25 PM, Enrico Lazzerini wrote:
> I thought to this with a 7808:
> to test before to resolder the new LB1620.
> Thanks for the kind support of all of you.
If you cut where you indicate and install the 7808 across that point, you will miss the supply point for the hall-effect sensors, they would still be supplied by the higher zener V (note R109 that takes off around the R112-D102 junction to head to the sensors).
Rather than cutting the trace, I would just remove R112 & D102 and install the 7808 across the former R112 opening, with the aforementioned diode(s) in the GND leg. There's enough copper there you may be able to drill a new hole or two to catch the 7808 legs.
(Alternatively, 9.1V zeners are pretty common.)
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