TECH: Time Pilot

Archived from groups: rec.games.video.arcade.collecting (More info?)

Steve,

Look for a diode inline with the +12 on the board. It would serve as a
reverse polarity protection diode. If it is bad it would explain a LOT
fo your problems (Ie, someone hookd up the PS wrong and plugged in the
edge connector backwards) You can clip it out for testing as long as
you promise to hook it up right while testing  

Other things to look for would be a bad tantalum cap (shorted) or a
bad op-amp or main op amp. Simply follow the schematic to the power
input legs on the op amps and clip out ground legs and measure one at a
time; if the first two culprits I mentioned turn up good.

When your power input line is no longer reading 27 ohms you've found
the bad guy.

- Matt

Archived from groups: rec.games.video.arcade.collecting (More info?)

Steve Muccione <home*DOT*muccione@verizon.net> wrote:
: does anyone know what the load on the 12 v line is supposed to be?
:
: I'm reading 26 ohms from the 12v input to ground which would give me a draw
: of over 2 amps... seems kind of hi to me (I'm also not getting any sound)
: and it keeps tripping the supply on the 12v

No, that's a current draw of under .5A. Considering that it probably only
powers the audio amp, you've probably got a bad tantalum or electrolytic,
or perhaps a blown audio amp.

--
Mark Spaeth mspaeth@mtl.mit.edu
50 Vassar St., #38.265 mspaeth@mit.edu
Cambridge, MA 02139
(617) 452-2354 http://rgvac.978.org/~mspaeth

Archived from groups: rec.games.video.arcade.collecting (More info?)

Thanks Matt,

I saw those 2 diodes there and figured that would be my first stop.... I
only had a small window yesterday to look at it but should have more time
this week (especially if my DSL continues to be f'ed, at which point I'll
have a LOT of time...grr...).

I'll post back and let people know what I find for the record.

best,

steve

"Matty-t" <matthews@audio-doctors.com> wrote in message
news:1122916328.449987.277540@g43g2000cwa.googlegroups.com...
> Steve,
>
> Look for a diode inline with the +12 on the board. It would serve as a
> reverse polarity protection diode. If it is bad it would explain a LOT
> fo your problems (Ie, someone hookd up the PS wrong and plugged in the
> edge connector backwards) You can clip it out for testing as long as
> you promise to hook it up right while testing  
>
> Other things to look for would be a bad tantalum cap (shorted) or a
> bad op-amp or main op amp. Simply follow the schematic to the power
> input legs on the op amps and clip out ground legs and measure one at a
> time; if the first two culprits I mentioned turn up good.
>
> When your power input line is no longer reading 27 ohms you've found
> the bad guy.
>
> - Matt
>

Archived from groups: rec.games.video.arcade.collecting (More info?)

god damnit...

still can't divide...

Thanks Mark, write back on what I find.

best,

steve

"Mark C. Spaeth" <mspaeth@plancherel.mit.edu> wrote in message
news:42ee5980$0$564$b45e6eb0@senator-bedfellow.mit.edu...
> Steve Muccione <home*DOT*muccione@verizon.net> wrote:
> : does anyone know what the load on the 12 v line is supposed to be?
> :
> : I'm reading 26 ohms from the 12v input to ground which would give me a
> draw
> : of over 2 amps... seems kind of hi to me (I'm also not getting any
> sound)
> : and it keeps tripping the supply on the 12v
>
> No, that's a current draw of under .5A. Considering that it probably only
> powers the audio amp, you've probably got a bad tantalum or electrolytic,
> or perhaps a blown audio amp.
>
> --
> Mark Spaeth mspaeth@mtl.mit.edu
> 50 Vassar St., #38.265 mspaeth@mit.edu
> Cambridge, MA 02139
> (617) 452-2354 http://rgvac.978.org/~mspaeth
>