Green Battery Question

[Foster]

I  stand by my previous post to use a resister to allow a 10-30ma current to flow through the resistor, so the circuits involved detect a charging a battery (that is not there)

In my high school electronics class, we had to calculate and measure the internal resistance of a battery and DC power supply
I have forgotten exactly how to do so but I can figure it out.
if you do not think they have resistance in both, think again!

[Neonkiss]

I  stand by my previous post to use a resister to allow a 10-30ma current to flow through the resistor, so the circuits involved detect a charging a battery (that is not there)

In my high school electronics class, we had to calculate and measure the internal resistance of a battery and DC power supply
I have forgotten exactly how to do so but I can figure it out.
if you do not think they have resistance in both, think again!

[PLUNGER BOY]

I would feel safer putting a 150, 180 or 220 ohm resister between the + and - to protect the charging circuits and that allow 10mA to 20mA current flow depending on the actual voltage from the charging circuit.

OK so which of the above resisters would allow the correct amount of current flow with out the green battery to fool the board and make it think the battery was there .

[CommTech]

DO NOT short the terminals together ;  All you are doing is burning up the charge circuit.  Just remove the battery and be done with it.  No need for any resistors.
I see nothing in the schematic to indicate that a charge current would be detected by any other circuit other than the circuitry that regulates the charging current.
Like Foster said ... It is simply a BACKUP power source for the TT circuit. 

[bhinkley]

Without the battery there you will get door sensor errors without a jumper of some sort there

[CommTech]

Without the battery there you will get door sensor errors without a jumper of some sort there

 
I have no idea why you would be getting door sensor errors without shorting out the charger circuit. 
With no battery, you get zero volts on the TT sensor line (Power off)
With no battery and shorted terminals you get zero volts on the TT sensor line (Power off).
So whats the difference?

[bhinkley]

Not sure.  It took us a while to figure out that is where the issue was though.

[Foster]

This will require some experimentation to be sure

When the battery is not connected in an Enhanced board the board to me looks like something is continuously resetting the board  which should only happen one time after power is stable
I forgot what the MPU LED's were doing with no battery connected.

Most all complex computer boards have a reset that occurs shortly after power up.

[leapyearguy]

This will require some experimentation to be sure

When the battery is not connected in an Enhanced board the board to me looks like something is continuously resetting the board  which should only happen one time after power is stable
I forgot what the MPU LED's were doing with no battery connected.

Most all complex computer boards have a reset that occurs shortly after power up.

this could account for the flashing netplex down syndrom that has been discussed here a lot lately.

[proten]

Why not just replace it with a new battery?

Jameco sell that battery for $5.25

[stayouttadabunker]

Why not just replace it with a new battery?

Jameco sell that battery for $5.25

That's too easy Proten! 
We don't learn anything doing thing's the easy way!!! 

[Neonkiss]

I actually get mine from Mouser

http://www.mouser.com/ProductDetail/Varta/COMP-18-3-NMH/?qs=sGAEpiMZZMsG1k5vdNM/cwKX2CU%252b1oyF

These are the original batteries at 150mah
I would perfer to remove the battery all together to prevent corrosion damage.
If you see ANY blue corrosion around the battery area, replace the battery.

[bhinkley]

The reason for wanting to remove the battery is simple.  When you have one that leaks acid and gets the corrosion as Neon mentions, if it is not caught quick enough and gets onto the MPU surface it can damage the traces on the board and poof you have a useless MPU, so a $6 battery becomes a whole new board instead.

I know this is a different machine entirely, but using it as an example.  The shop I work at used to be able to get the old Bally 500 boards if I remember which ones they were for like $40.  then demand went up for them due to an issue going on and the prices skyrocketed, so they are still showing about $250 for the same board.  That is the point of removing the battery is preserving the boards so people don't have to pay inflated prices later because of a battery destroying the whole board with an acid leak.

[edski]

The reason for wanting to remove the battery is simple. 

Fully understand why battery removal is wanted.

We electronical types don't understand how shorting out the circuit helps, or fixes, or solves anything??????

[proten]

Could it be the connecting of the + pos. contacts?

[bhinkley]

I tested a theory today.  I just jumpered the two positives before birthing a machine, and it doesn't even allow you to clear the EEPROM without the + and - connected