Re: checking electrolytic caps

From: Clockmeister <>
Date: Mon, 29 May 2017 08:06:17 +0800
Message-ID: <>
On 29/05/2017 7:50 AM, Terry Raymond wrote:
> Hi
> Im needing to check all Caps on my C128
> to check these would I read the caps in OHM's readings?
> Im going to desolder them one at a time just to know what ones are failing
> and if the
> Electrolytic is leaking out or the CAP has a bulge on the top.

If you are going to the trouble of desoldering them, just replace them 
but do so with quality caps.

> This C128 is blowing the fuse in the power source, and this power source
> has been built from scratch from Ray Carlsen in the U.S.A. I trust Ray's
> work so it must be something on the
> C128's MB circuit.

I trust Ray's work too, but that is not to say something hasn't failed 
in the supply. Does the fuse blow as soon as you power up the C128?
If there is a dead short in Ray's supply I would suggest that the supply 
fuse will blow even if the C128 isn't turned on.

> I was also told isnt there a power regulator component that has 3 solder
> legs that could possibly
> cause power problems, Should this regulator read 12VDC?   What legs do I
> probe when I read the voltages on this regulator?

If it's a 78xx Voltage regulator then see here:

Pin 1 is input voltage, 2 is ground and 3 will be the regulated output 
voltage which should match the last two digits after the 78 part number. 
IE 7805 = 5V, 7812 = 12V.

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Received on 2017-05-29 01:00:02

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