Hello!
I wanted to add the reset switch to my ram expansion cart.
I understand the switch should bridge the RST pin with ground.
Unfortunately, on my cart the reset pin is not connected, no copper line there.
Is there an easy way to add the missing copper in order to be able to solder a wire to it?
Please consider I've got very basic soldering and pcb training
pallas wrote:Hello!
I wanted to add the reset switch to my ram expansion cart.
I understand the switch should bridge the RST pin with ground.
Unfortunately, on my cart the reset pin is not connected, no copper line there.
Is there an easy way to add the missing copper in order to be able to solder a wire to it?
Please consider I've got very basic soldering and pcb training
I have used copper tape for similar assignments. The good thing with VIC-20 technology is that it is very forgiving. Everything is huge and with nice tolerances.
That said. The keyword here is "easy". It DOES take practice and knowledge with the iron.
So I guess I would also go for the user port for a reset switch.
pallas wrote:Hello!
I wanted to add the reset switch to my ram expansion cart.
I understand the switch should bridge the RST pin with ground.
Unfortunately, on my cart the reset pin is not connected, no copper line there.
Is there an easy way to add the missing copper in order to be able to solder a wire to it?
Please consider I've got very basic soldering and pcb training
I do not recommend it, but if you're a "handyman" and you absolutely want to make the reset switch that way, you could take some copper, be it from a wire or tape. Then glue that copper on to the empty place. When it's totally hardened, you can file it till it's absolutely smooth like the rest of the traces. You could use a file or a glass fiber pen.
However I think it’s a very precise job and you should consider if it's worth the risk.
Wouldn't it be possible to just short the output of the 7404 coming out of the 555 reset timer through a 300 ohm resistor to ground? This would effectivly pull the reset signal low correct?
That is basically what you would do anyway, when you reset through userport, cartridgeport or the IEC serial port. They all go together. Even without the resistor. 300ohms might be a bit high, since it is pulled up with a (nowadays) rather low pull-up of 1k). Usually it is just shorted to ground.
The inverter on the 555 output is actually a 7406, which is the open collector version.
TLovskog wrote:That is basically what you would do anyway, when you reset through userport, cartridgeport or the IEC serial port. They all go together. Even without the resistor. 300ohms might be a bit high, since it is pulled up with a (nowadays) rather low pull-up of 1k). Usually it is just shorted to ground.
The inverter on the 555 output is actually a 7406, which is the open collector version.
heh didn't have the schematic in front of me to check
So a dead short would work then. I just figured that there would be an available solder point on the main board rather then bothering with a connector. Personally I have not had a need for a reset button at the moment. That will probably all change as I start programming more machine code
OK guys thanks for the info.
I went for the safe route: soldered a wire to pin 6 of the sd2iec connector, then a switch to ground (taken on the video connector). Works fine!
