Re: Need some help with an Atari Switching Power Supply

Here's an update on the I,Robot power supply. I put in the new FEP16CTA
part and now the power supply works fine. The game and monitor come up
fine. So if anyone is trying to fix their I,Robot power supply - the
schematics have that part number wrong. Whoever worked on this before me
put in the wrong part and probably gave up.

The regulator is regulating at 5.4 volts. Perhaps I need to look at the
sense line? When I measure from ground to the speakers I'm getting around
-36volts. I'm getting alot of crackly hiss through the speakers. Almost
sounds like radio interference. I'm supposed to be getting around -31.5
volts so I'm thinking that might be why. I don't think it's just a bad
volume potentiometer.

Other than that, I'm still waiting for my order of ram chips to come in.
The screen is all full of dots and is reporting a bad ram.

Almost there! :)

Matt

 
On Fri, 18 Jul 2008 15:17:56 +0000 (GMT+00:00), teeray
<teeray@earthlink.net> wrote:
>
> Check and make sure the grounds for the speakers are not connected
> to any other ground or metal object.
> The speaker ground is at -31.5 Volts.
> Treat it just like it was a power wire.
> No bare spots, etc.
>
> Tim
>
>
>
> On Jul 17, 2008 2:08 AM, Matt Rossiter
> Wrote:
>>
>>This is just a little update. When I removed L6 the +5v came up just
> fine
>>and the regulator didn't shut down.
>>http://games.rossiters.com/manuals/IR-PS2-1.jpg
>>So the problem is definitely in the audio section of the board. I'm
> still
>>trying to find where the problem is. I've replaced the audio amps and
> some
>>of the capacitors. I can't find any bad resistors. There seems to be
> loose
>>a ground somewhere because if I touch something metal like the coin door
>>frame or the power switch I can feel a slight tingle of electricity. Not
> a
>>huge shock, but enough to be a little uncomfortable. I'm wondering if
> that
>>might have something to do with it.
>>
>>The boards seem to work fine with the ribbon connectors I made. It's
>>reporting a bad ram, but I'm not going to keep powering the boards up
> until
>>I resolve this loose ground issue.
>>
>>Matt
>>
>
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Received on Tue Jul 22 02:39:53 2008