Posted By
Gary
on 2016-08-26
06:05:34
|  Plus 4
Hello I bought a Plus 4 from Ebay a while back and only got it setup last night - this is my 1st plus 4 so completely new to it.
Everything is great except the DOWN on the joystick does nothing - all other directions + fire work fine
At first I thought it was a bad contact on the joystick but I was able to trace it actually working all the way back to the ferrite beads on the board and all is good.
Then I think I got it traced directly to the "TED" chip, so when I pulled down on joystick I could see continuity OK on the pin.
Problem is (I think this might have been a bad idea) I put my working TED from my Commodore 16 into the Plus 4 and it is exactly the same ! so I hope I havent blown my good TED too 
Are there any other chips I need to check that handle Input ?
thanks in advance
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Posted By
Gary
on 2016-08-26
10:49:31
| Re: Plus 4
It's OK I got it sorted, the Diode CR12 was faulty !
Just in case this is of use to someone else !
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Posted By
Gary
on 2016-08-26
10:53:42
| Re: Plus 4
PS it is a 1N4148 Signal Switching Diode High Speed btw
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Posted By
SVS
on 2016-08-27
05:16:04
 | Re: Plus 4
There is a little electronic card named "TED protection" (designed by Solder) that acts the protection of TED chip from joysticks contacts. If I well remember it has further advantages too.
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