Re: Commodore 65 and DIN8 cable

Date: Wed, 2 Mar 2016 21:29:30 +0100
Message-Id: <>
> On 2016-03-02, at 17:18, Michał Pleban <> wrote:
> Hello!
> wrote:
>> If you have valid schematics at hand, please check if those are only capacitors there. There might be other elements like Rs, FBs, ... Checking all of them under highly magnifying glass could sometimes reveal the cause too. I had a situation when an FB was seemingly intact but was in fact mechanically broken. When measuring, the pressure caused the problem to disappear but it became apparent when perusing under magnification and differently applied pressure.
> The schematic shows a box labeled "EMI", I don't know what that might be?

Those can be various things. CBM is known to load those with a number of "funny things" (they even had this wording on the schematics). Theoretically though, those should be so called EMI filters with three legs.

> Would it make sense to solder tiny wires to short each of these "EMIs"
> under the board? They could be unsoldered, returning the board to
> original state if required.

You'd need to remove the filters first. Then you could jumper the signal over. But if the U1 is removable then you should be able to make the lines "open" and measure thoroughly all of them.


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Received on 2016-03-02 21:00:51

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