RTC megaST4

[Bikerbob]

Any reason why you cannot just change the std AA batteries for a 3v coin battery?

rtc battery mega.jpg

This is the circuit. Do I need to go positive to pin 1 and neg to pin 2.. or can I take neg direct to ground?

James

[joska]

Any 3V battery should do. The Stacy has the same RTC and use a coin cell. You can connect connect the battery negative pole to ground.

[Bikerbob]

So.. thats what I thought.. but after install and battery installed.. I have killed the battery.. it is shorting out or something.. I am going from the gnd edge of the motherboard then to pin 1. I will Quadruple check.. mabye I reversed it.

James

[mpattonm]

If you have multimeter, check that D4 too. Or check, if there is a measurable voltage between pins 1 and 2 with no battery in. The diode may be in reverse or short and 5V PSU is killing the battery.

[Bikerbob]

If you have multimeter, check that D4 too. Or check, if there is a measurable voltage between pins 1 and 2 with no battery in. The diode may be in reverse or short and 5V PSU is killing the battery.

Yep have a good MM with Diode check.. voltage in one direction, none in the other.. that part is fine. guess I get a new battery and check it without and with power. its a puzzle.. other thing I could do it run a jumper wire from pin 2 to the ground on the coin holder, see if that changes anything.. it shouldnt.

James

[tzok]

Pin 2 is grounded anyways, battery + to the anode of D4.

[Bikerbob]

So.. I was not able to get it work without passing it through pin 2.. why?? no idea.. it SHOULD work off any ground.. but did not. I used pin 2 with a couple of wire now to the coin holder, and it seems to be working fine. (one thing on the machine anyway )