MOTM

So I finally got a chance to test my MOTM-900 this weekend.  And of course,
my DVM reports 0 volts across the COM / -15V or COM / +15V terminals on the
power supply.  I'm testing them by putting the DVM leads up against the base
of the terminals, since the rest is covered in shrink wrap.  I'm not sure
what's going on, but here's what I've tried so far:

1) Changed batteries in DVM.
2) Changed power cords and sockets going into MOTM-900, including using one
known to be good.
3) Visually checked and rechecked all wirings / configurations against the
pictures on the last page of the instructions.
4) Made sure it was turned on.

At this point, I'm unconvinced that the DVM is working properly.  I'm
thinking I'm going to test it on a wall-wart that I know is good.  Is there
any danger in doing this?  Does anyone have any other debugging advice?  I
don't think I have any other +15 / -15 devices that I can simply plug in,
and I want to get this handled before starting on the other modules.  (I
don't even want to imagine the frusteration of debugging a kooky power
supply AND module at the same time...)

Thanks!

--PBr

Are you sure you have the fuse installed (I think it goes inside the power 
connector, but I can't remember)? Let's just say I know someone who made such 
a mistake, but thankfully found out before making a fool of himself by 
posting to the list -- but he usually makes a fool of himself with his other 
posts anyway (in stoogeular physics we refer to this as the conservation of 
stupidity).

JB

Test your meter:

Set your DVM to DC volts and see if it will measure a battery, like a 9
volt. Any good AA, A , C, or D cell should read around 1.5 volts.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

> -----Original Message-----
> From: Brousseau, Paul E (Paul) [mailto:PaulBr@...]
> Sent: Monday, December 20, 1999 4:16 PM
> To: 'motm@onelist.com'
> Subject: [motm] MOTM-900 debugging advice...
>
>
> From: "Brousseau, Paul E (Paul)" <PaulBr@...>
>
> So I finally got a chance to test my MOTM-900 this weekend.  And
> of course,
> my DVM reports 0 volts across the COM / -15V or COM / +15V
> terminals on the
> power supply.  I'm testing them by putting the DVM leads up
> against the base
> of the terminals, since the rest is covered in shrink wrap.  I'm not sure
> what's going on, but here's what I've tried so far:
>
> 1) Changed batteries in DVM.
> 2) Changed power cords and sockets going into MOTM-900, including
> using one
> known to be good.
> 3) Visually checked and rechecked all wirings / configurations against the
> pictures on the last page of the instructions.
> 4) Made sure it was turned on.
>
> At this point, I'm unconvinced that the DVM is working properly.  I'm
> thinking I'm going to test it on a wall-wart that I know is good.
>  Is there
> any danger in doing this?  Does anyone have any other debugging advice?  I
> don't think I have any other +15 / -15 devices that I can simply plug in,
> and I want to get this handled before starting on the other modules.  (I
> don't even want to imagine the frusteration of debugging a kooky power
> supply AND module at the same time...)
>
> Thanks!
>
> --PBr
>
> >

Duuhhhhhh...  

--PBr, looking for that dunce cap.

(Reguarding the fuse... I know its in there.  Is it directional?  And if so,
how can I tell direction?  I didn't see any such markings.)

> -----Original Message-----
> From:	Dave Bradley [SMTP:daveb@...]
> Sent:	Monday, December 20, 1999 2:24 PM
> To:	motm@onelist.com
> Subject:	RE: [motm] MOTM-900 debugging advice...
> 
> Test your meter:
> 
> Set your DVM to DC volts and see if it will measure a battery, like a 9
> volt. Any good AA, A , C, or D cell should read around 1.5 volts.
>

In a message dated 12/20/99 4:15:38 PM, PaulBr@... writes:

>(Reguarding the fuse... I know its in there.  Is it directional?  And if
>so,
>how can I tell direction?  I didn't see any such markings.)

No, it's not. I would start by check the AC part of the 900 as well 
(carefully) with the meter in the AC setting up to the transformer.

JB

OK, I didn't think it was directional, but best to ask stupid questions...
;)

Is there anything I need to know about testing AC?  My meter is actually a
multi-meter, so I just set it to AC, 200V, and test negative-ground and
positive-ground, as with the DC (say, without making any contact myself)?

--PBr

> -----Original Message-----
> From:	JWBarlow@... [SMTP:JWBarlow@...]
> Sent:	Monday, December 20, 1999 3:24 PM
> To:	motm@onelist.com
> Subject:	Re: RE: [motm] MOTM-900 debugging advice...
> 
> In a message dated 12/20/99 4:15:38 PM, PaulBr@... writes:
> >(Reguarding the fuse... I know its in there.  Is it directional?  And if
> >so,
> >how can I tell direction?  I didn't see any such markings.)
> 
> No, it's not. I would start by check the AC part of the 900 as well 
> (carefully) with the meter in the AC setting up to the transformer.
>

In a message dated 12/20/99 4:28:27 PM, PaulBr@... writes:

>Is there anything I need to know about testing AC?  My meter is actually
>a
>multi-meter, so I just set it to AC, 200V, and test negative-ground and
>positive-ground, as with the DC (say, without making any contact myself)?
>

No, that's it! You might as well check to make sure the fuse is still OK too.
JB

Er, for the list's reference, according to Paul S. (who's job it is to know
these things), you test positive-negative on the AC... NOT ground-negative
and ground-positive as I thought.  Don't you all go killing yourself over my
mistakes.  ;)

--PBr

> -----Original Message-----
> From:	JWBarlow@... [SMTP:JWBarlow@...]
> Sent:	Monday, December 20, 1999 4:03 PM
> To:	motm@onelist.com
> Subject:	Re:[motm] MOTM-900 debugging advice...
> 
> In a message dated 12/20/99 4:28:27 PM, PaulBr@... writes:
> >Is there anything I need to know about testing AC?  My meter is actually
> >a
> >multi-meter, so I just set it to AC, 200V, and test negative-ground and
> >positive-ground, as with the DC (say, without making any contact myself)?
> >
> 
> No, that's it! You might as well check to make sure the fuse is still OK
> too.
> JB
>

Well, that (as they say) is a long story depending on what country you live
in.  However, in the USA, you should measure between 114 and 126 volts
between what is called neutral (the big slot) and hot (the small slot). 
The hot to ground (round hole) should also read about the same and the
neutral to ground should be very close to zero.

I make reference to the plug because I have seen guys work their way
backwards back a power supply only to find the outlet is dead.  However, as
opposed to twiddling test leads around in an outlet, I recommend just
plugging in a lamp.  Then get the voltmeter out.

Larry (expert high voltage stooge) Hendry

----------
> From: Brousseau, Paul E (Paul) <PaulBr@...>
> To: 'motm@onelist.com'
> Subject: RE: [motm] MOTM-900 debugging advice...
> Date: Monday, December 20, 1999 6:08 PM
> 
> From: "Brousseau, Paul E (Paul)" <PaulBr@...>
> 
> Er, for the list's reference, according to Paul S. (who's job it is to
know
> these things), you test positive-negative on the AC... NOT
ground-negative
> and ground-positive as I thought.  Don't you all go killing yourself over
my

> mistakes.  ;)
> 
> --PBr