dhau
Experienced Member
I bough an IBM PC 5150, and inside it had two Quadram Quadboards from 1982. Both had their rechargeable batteries already removed. I'd like to add coin CR2032 batteries to those boards. Did anyone do it before?
As I understand, I have to put a diode in series with the battery to prevent charging current from messing with the battery. Also, if I understand it right, when the card is powered from the power supply, diode is cutting off the battery, so it doesn't discharge while PC is on. To prevent a significant drop in voltage, I should use a schottky diode like 1n4001, not a zenner diode like 1n914. I should also have a 100 Ohm resistance in series with battery and diode, as per OKI MSM5832 datasheet. Fortunately there is already a 100Ohm resistance between battery plus and chip Vcc pin.
Any advise or experience is very welcome!
As I understand, I have to put a diode in series with the battery to prevent charging current from messing with the battery. Also, if I understand it right, when the card is powered from the power supply, diode is cutting off the battery, so it doesn't discharge while PC is on. To prevent a significant drop in voltage, I should use a schottky diode like 1n4001, not a zenner diode like 1n914. I should also have a 100 Ohm resistance in series with battery and diode, as per OKI MSM5832 datasheet. Fortunately there is already a 100Ohm resistance between battery plus and chip Vcc pin.
Any advise or experience is very welcome!