Wiring of the 97 paper advance switch


Could anyone tell me in which order I should resolder the red, black and white wires on the 97 paper advance switch. They just broke off while I openned it to show my repairs. I don't have notes on this.

The service manual tell me to check continuity between black and red but I can not find more information.

Thanks for your help.


Edited: 11 Nov 2005, 4:56 p.m.


| R | ed
| B | lack
| W | hite
| | +---------------------
| +-+ xxxxxxxxxxxxxxx
| printer daughter board pins


Thanks for your answer but I am looking for the other end of the wires.

I know that when not pressed I should have close circuit between Red and Black so the white wire has to be soldered to the centre of the switch.

One of the other pins seem to be always open circuit and the other close circuit with the centre one when pressed.

Which one is which????



Edited: 12 Nov 2005, 10:48 a.m.


Yes, the service manual does not properly explain the switch wiring.

I can't remember the colours, but I think I can remember what the 3 switch contacts should connect to. Maybe that will help. It's a changeover switch, there is a common tag, a normally-closed tag and a normally open tag. When the button is not pressed, there's continuity between 'common' and 'normally closed'. When it is pressed, there's continuity between 'common' and 'normally open'.

The common tag is electrically connected to logic ground. The -ve side of the battery is also ground

The normally closed tag is electrically connected to one of the pins to the printer PCB, and via that PCB to one of the out-of-paper contacts in the printer.

The normally open tag is electrically connected to one of the flag inputs on the ACT chip (22 pin). I think it's either pin 3 or 4

A bit of work with a continuity tester should tell you which of the 3 pins on the logic board is which, then you can connect them to the right switch pins.


Thanks a lot, that is exactly what I was looking for. Now just a bit of cleaning and soldering to do.

Just for the Archive, GND is Black normally closed connected to OOPS Red. This is indicated in the service manual. White is ACT normally open connected to GND Black when the switch is pressed.


Edited: 13 Nov 2005, 6:56 a.m.

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