Re: Re[2]: Omega Race - help!

For those who don't have a scope in their arsenal, set your DMM/VOM to AC
and measure the AC ripple on the bulk DC lines. More than a couple tenths
of a volt and there most likely isn't sufficient capacitance to do the job
(meaning the caps are going bad / gone bad, or their isn't sufficient
capacitance to begin with). On regulated output lines, you shouldn't
have more than 50-100mV or so of riple when loaded. FYI - this really
only works on linear supplies, not switching supplies.

Remember, you can replace electrolytic caps with a working voltage higher
than what's there now, but not lower (unless you know the original
values, or know the design _really_ well).

Oh, and watch polarity too, or you'll have a noisy, smelly, confetti-like
party favor in short order :)

Brad

On Fri, 25 Jan 2008, peter jones wrote:

>
>
> -----Original Message-----
> From: "Lewis D'Aubin" <ldaubin@bellsouth.net>
> To: vectorlist@vectorlist.org
> Date: Wed, 23 Jan 2008 18:21:03 -0600
> Subject: Re: VECTOR: Omega Race - help!
>
>>
>>> Based on the schematics in the service manual, it does indeed look as
>>> if the game can be strapped for multiple different input voltages. If that
>>> were the case, though, it looks as if your +12V should be low as well. Have
>>> you checked that?
>>
>> I finally printed out a nice large drawing of page 92 (96 on the PDF).
>> OK, yeah, +12 is dragging as well - it's at 10.79 with the pot all the
>> way up.
>>
>> Checking the transformer inputs, it's tapped at 120V, so that's correct.
>> Unreg'd input to the power supply board is 8.57V for the '8V' input and
>> 16.79V for the '15V' input. Hmmmmm.... maybe it's the linear power
>> supply board after all.
>>
>>
> generally with linear supply's, if your ac is good and your dc looks wrong it's probably your primary smoothing capacitors after the rectifiers that are gone.
> a scope will prove that one.
>
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Received on Fri Jan 25 09:29:23 2008