Battery Issue in MP-1

[kfowler8]

Hey guys. Got an issue with my MP-1. Something seems to be draining the battery. I only get about one month of battery life when I replace it. I then get the error boot message when the memory has been wiped clean. I replace the battery and it works fine for about a month.

Any ideas with this? Isn't there a way to swap the it out so you don't need to use a battery?

Thanks,

Kevin

[kfowler8]

This is what I was thinking of.

Anyone try this?

http://www.kylheku.com/lurker/message/20131111.161931.09863a88.en.html#ada-mp1/

[MarshallJMP]

Try to replace D43 and C137,could be one of these is leaking.See attachment.

[kfowler8]

Thanks! I'll give that a shot

[kfowler8]

Try to replace D43 and C137,could be one of these is leaking.See attachment.

What values are these? I can't quite make out what it says on the schematics.

Thanks

[MarshallJMP]

C137 is a 0.1µF cap and the diode i think is a 1N4148.

[kfowler8]

C137 is a 0.1µF cap and the diode i think is a 1N4148.

Thanks again!

[kfowler8]

OK guys. Need some help again. I replaced the cap and diode mentioned above. It's been a month and the battery is dead again. So something is causing it to leak. Bummer too because I was planning on using it for Easter weekend.

Is there a way to take my multi-meter and test the draw on the battery? Any ideas what else it may be? What about the batteryless mod? Thanks!

[rnolan]

Hadn't heard of a battery-less mod ?? the RAM which stores the program settings has to have power to stay storing. So do tel ?? Some batteries just die BTW, although I get that it may be a leak. Worth considering that the battery you installed was close to retirement anyway ?? Just a thought worth checking. I can't think what would drain it so fast, MJMP territory here...

[kfowler8]

Hadn't heard of a battery-less mod ?? the RAM which stores the program settings has to have power to stay storing. So do tel ?? Some batteries just die BTW, although I get that it may be a leak. Worth considering that the battery you installed was close to retirement anyway ?? Just a thought worth checking. I can't think what would drain it so fast, MJMP territory here...

Thing is this is like the third battery it's done it to. Very odd.

The batterless mod talks about taking out the SCRAM chip and replacing it with a EEPROM chip. I think I may give this a shot but I'm going to have to find some time to tackle it. I'll post the results if I do it.

[rnolan]

Wow that's weird,  let us know how you go (and "no" battery dependency is desirable, so EEPROM chip acts like RAM but holds between sessions, good way to solve it), but we should also put some thought into why your battery is draining, particularly as my old MP1 battery has only just died after 25 years.

[kfowler8]

Wow that's weird,  let us know how you go (and "no" battery dependency is desirable, so EEPROM chip acts like RAM but holds between sessions, good way to solve it), but we should also put some thought into why your battery is draining, particularly as my old MP1 battery has only just died after 25 years.

I pulled the MP-1 apart last night. Any chance it has something to do with a bad battery clip install? The solder joints look good but I've thought about pulling the clip and replacing it just to be sure.

[rnolan]

Well can't hurt, and "may" fix it ?? (hope it does) Sounds like a good plan to me. If it doesn't fix it... then why is battery draining so fast ????

[MarshallJMP]

Since the battery power the RAM chip and U44,maybe one of these is faulty.You could try to replace the RAM (6264 or 5864).These are quite cheap so you could give it a go if the clip replacement doesn't work.

As for measuring the current,well there is a way but you will need a good digital voltmeter that can measure mV.You could measure over R245. Current = voltage over R245 x 6.2

[kfowler8]

Since the battery power the RAM chip and U44,maybe one of these is faulty.You could try to replace the RAM (6264 or 5864).These are quite cheap so you could give it a go if the clip replacement doesn't work.

As for measuring the current,well there is a way but you will need a good digital voltmeter that can measure mV.You could measure over R245. Current = voltage over R245 x 6.2

May give that a try. I have a Fluke 16 digital multimeter.