4 Attachment(s)
Anilam 1100 motherboard battery replacement
Just bought a knee mill with 2-axis Anilam 1100 control. The battery on the motherboard was starting to corrode and leak, so I have the motherboard out and removed the battery from the board.
I am looking to replace the internal Varta 3.6v barrel battery with a 3x AA external battery holder wired to the external battery pins, but nobody can tell me how exactly to get this done. There is a jumper that needs to be removed to switch from the charging internal circuit, to the external non-charging circuit. I know where that is, but I have no idea which pins to attach the 3x AA wires to.
I have communicated with Gerald (Jerry) Bouvier, an ex-engineer of Anilam, and he doesn't seem to remember how he did it a long time ago, other than he bought a battery with a connector already on it and just plugged it in. ...which doesn't help me much. Also, I can't seem to find anybody that knows much about the old 386SX boards to get me through to a viable solution.
I would rather not just solder another Varta battery to the motherboard, as there is great potential for them to leak and screw up the board all FUBAR, and it is a pain getting the motherboard out to do another replacement. I have thought about using rechargeable AAs in the holder, and soldering to the internal battery vias, but I am not sure if the onboard charging circuitry will be overtaxed by charging 3x 2000mAh batteries and put me in an even worse position.
I will attach some pics of the battery circuitry and external pins, hopefully, there is someone here that has been through this and can give me a solution to my dilemma.
Thanks!
Re: Anilam 1100 motherboard battery replacement
Don't worry, a higher capacity rechargeable battery will work fine there. The charging circuit provides very small trickle charging current, it will not be damaged by a larger battery.
Re: Anilam 1100 motherboard battery replacement
Well, I was just thinking about how a low amperage wall wart cell phone charger gets really hot when someone tries to charge a tablet that has a much larger battery that demands more current than the charger can put out. I don't want to cook something else somewhere else on the board. Maybe a diode could be placed on the lead from the battery holder to totally inhibit charging of the batteries???
Re: Anilam 1100 motherboard battery replacement
Quote:
Originally Posted by
SoggyBottomBoy
Well, I was just thinking about how a low amperage wall wart cell phone charger gets really hot when someone tries to charge a tablet that has a much larger battery that demands more current than the charger can put out.
We are talking about much smaller currents here. See resistor R4 on your photo? It's 1KOhm. Assuming it's connected to the 5V bus, the trickle charging current is only 1.5mA and the short circuit current is only 5mA. So there is no chance to damage the board no matter how large your battery is.
If you still feel unsafe about charging, you could use 3x alkaline batteries and 3x 1N4007 diodes in series. That should give you about the right voltage.
1 Attachment(s)
UPDATE: Anilam 1100 motherboard battery replacement
***UPDATE***
Success! I have connected the 3x AA battery holder to the external battery pins. Positive lead to Pin 1, Negative lead to Pin 4
After consulting with an online group of vintage computer enthusiasts, they were quite sure that after removing the jumper, Pin 1 would be for the positive lead & Pin 4 would be the negative lead of my battery holder. They cautioned that I should make sure that Pin 4 had continuity to ground, and after probing with a volt/ohm meter, I verified that Pin 4 was ground.
I removed the OEM wires from the battery holder, and soldered 12" long Dupont (22 AWG) leads directly to their corresponding points within the holder. Inserted the wire terminals into a 1x4 female connector to push onto the pins, and routed the wires so that the battery case is on the outside of the computer case for easy access for battery replacement.
Now, I just have to figure out how to get into the BIOS to see what needs to be done. I'm not sure if I need to have an external keyboard hooked up to do that, or not. I think the oldest keyboard that I have has a PS/2 DIN6 connector on it, and the control box on the mill has a DIN5 port on the back. Fun, fun, fun!
