Re: checking electrolytic caps

From: Terry Raymond <traymond20_at_gmail.com>
Date: Thu, 1 Jun 2017 12:01:32 -0600
Message-ID: <CAEFCF-q12wkQAKY5V-28Q8bLaxARi-LOmL8rGXAgWNjqdyQ5gQ@mail.gmail.com>
Okay is the rectifier the same one found on a C64?

Can I find these like on Jameco or DIGI key or Unicorn electronics?

I could Rob one from one of my breadbin.☺

Will try the rectifier first to see if the fuse problem goes away.

Thanks

On May 30, 2017 8:53 AM, "Gerrit Heitsch" <gerrit@laosinh.s.bawue.de> wrote:

> On 05/30/2017 04:44 PM, Terry Raymond wrote:
>
>> Hi Clockmeister,
>>
>> This power source has a pigtail for powering the C64 works fine doesn't
>> blow it's fuse
>> Just when powering up the C128.
>>
>> This is helpful enough to find what regulator I need.
>>
>
> You might want to check the bridge rectifier in the C128. If one of the 4
> diodes in it has a short it will blow the fuse. It's the black square next
> to the power switch.
>
>  Gerrit
>
>
>
>
>
>
>> Terry
>>
>> On May 28, 2017 6:06 PM, "Clockmeister" <clockmeister@internode.on.net
>> <mailto:clockmeister@internode.on.net>> wrote:
>>
>>
>>
>>     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:
>>     https://www.engineersgarage.com/electronic-components/7805-
>> voltage-regulator-ic
>>     <https://www.engineersgarage.com/electronic-components/7805-
>> voltage-regulator-ic>
>>
>>     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.
>>
>>
>>
>>            Message was sent through the cbm-hackers mailing list
>>
>>
>
>       Message was sent through the cbm-hackers mailing list
>


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Received on 2017-06-01 19:00:03

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