----- Original Message -----
From: "Gunther Schadow" <gunther@aurora.regenstrief.org>
To: <port-vax@netbsd.org>; <classicmp@classicmp.org>
Sent: Thursday, May 31, 2001 1:33 PM
Subject: Re: Can one repair (large) blowers?


> The blower story: I opened all three non-working blowers down to the
> motor. Its quite a handful of motor and it looks like this is getting
> rather involved. I'd post a picture if my family hadn't taken the
> digital camera o their trip. This motor has lots of silicon on it,
> which I haven't taken the time to identify yet.

Just pulled one down, has six transistors and an IC.  Much like the
capstan motors you get in VCR's, no brushes etc.

> get to it too. I need a special tool to open the axle and even then
> it's going to be an electro-mechanical challenge.

Didn't get that far....

> I'm going to
> call the company who made it, AIRPAX in Connecticut, see if they
> know something. Tho I'm afraid this thing is expensive to replace
> new and expensive to have repaired. I guess I need to refresh my
> electronics knowledge for that :-/

Hmm, good starting point would be dry joints and electrolytics, then the
3 x TIP100 and 3 x TIP105 Transistors, then the motor control IC.
Can't quite see what that is yet.

> The one electrolyte capacitor on all of the three motors look O.K
> from from the outside. What could it be most likely that makes
> 3 out of 6 motors fail so completely?

Probably the same fault common to all.  Perhaps checkout the caps and
transistors first,
you should be able to get at the transistors without removing the board
from the looks of it.


Cheers

Geoff in Oz