4 Mar
2015
4 Mar
'15
2:22 p.m.
Sorry Brent, did you means like this pic?
https://www.dropbox.com/s/z5pj6lgbjos70fj/PowerSAFE.jpg?dl=0
Enrico
-----Messaggio originale-----
Da: cctech [mailto:cctech-bounces at classiccmp.org] Per conto di Brent Hilpert
Inviato: marted? 3 marzo 2015 23:49
A: General Discussion: On-Topic and Off-Topic Posts
Oggetto: Re: How to save two Mitsubishi M2896 drive (spindle motor smoked!)
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?
Brent wrote:
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:
https://www.dropbox.com/s/ekj0bftrh86nhsa/PowerOK.jpg?dl=0
to test before to resolder the new LB1620.
Thanks for the kind support of all of you.
Enrico
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.)
