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Thread: Boss ME 20 loses memory after shutting off

  1. #1
    Supporting Member Steve A.'s Avatar
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    Boss ME 20 loses memory after shutting off

    A friend has an ME 20 that he gigs with quite often and its memory is no longer persistent. Once he turns it off all of the settings (like the noise gate) are lost. We both think it is an internal battery which need to be replaced. Anybody here familiar with this? Like the number and source for the replacement battery...

    Thanks!

    Steve A.

    P.S. A Google search only finds hits for the 6 AA batteries... gee thanks, Mister Google!

  2. #2
    Supporting Member mozz's Avatar
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    I would think if you took it apart, you would see if there is a battery for the memory or not. I see dram and eeprom on ME-30.
    Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics

  3. #3
    Supporting Member Steve A.'s Avatar
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    Quote Originally Posted by mozz View Post
    I would think if you took it apart, you would see if there is a battery for the memory or not. I see dram and eeprom on ME-30.
    Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics
    My friend lives about 40 miles away so I was hoping that I would have a fresh battery on hand when he embarks on an 80 mile round trip.

    FWIW I have had some digital gear that needed an internal battery changed after ~10+ years, something usually omitted from user manuals.

    Steve A.

  4. #4
    g1
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    don't forget the joker g1's Avatar
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    Get him to pop the cover. If it has one, should be a coin cell with a visible number on it. Important to know if it is in a clip style holder, or solder tab style.
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  5. #5
    Senior Member Enzo's Avatar
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    Memory batteries in some less sophisticated or older models can be plain old AA cells. The drain from them for a CMOS RAM is tiny, they batteries essentially last their shelf life. But most are either rechargeable Nicads or then Lithium cells.

    The lithiums are usually coin cells, like the common CR2032. Since those lithium cells also last for YEARS, they are usually the solder-in type. Digikey or Mouser will have those. It is a coin cell with little solder legs welded on. You can't solder to a plain coin cell without destroying it. The battery is the same, solder lugs or not. I keep a supply of coin cell sockets on hand, and when I replace a soldered battery, I just mount a coin cell socket, and now anyone can pop a new CR2032 into it in seconds. BUy CR2032 at Radio Shack, the local grocery store battery display, wherever.

    Older things like synths from the 1980s used Nicads more. Those were kept charged whenever the unit was powered. and could hold a charge for months on end when off. I don't ever recall seeing a Nicad that wasn't a solder in, but no reason one couldn't mount a AA holder and use plain rechargeables.

    There is more than one footprint for coin cells with solder tabs. One has a pin in the middle and one off the edge. ANother has an edge pin but a flat tab on the center that bends down and has two pins.

    I don't think the six AAs on this are for memory, but I could be wrong.
    Education is what you're left with after you have forgotten what you have learned.

  6. #6
    Supporting Member Steve A.'s Avatar
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    Quote Originally Posted by Enzo View Post
    I don't think the six AAs on this are for memory, but I could be wrong.
    Of course you're right about the AA cells since they are not needed if you are using an AC adaptor.
    Thanks for such a comprehensive post... I will save it in my evergrowing archive of useful information.

    Quote Originally Posted by Enzo View Post
    You can't solder to a plain coin cell without destroying it. The battery is the same, solder lugs or not. I keep a supply of coin cell sockets on hand, and when I replace a soldered battery, I just mount a coin cell socket, and now anyone can pop a new CR2032 into it in seconds. BUy CR2032 at Radio Shack, the local grocery store battery display, wherever.
    Thanks for reminding me not to try soldering leads to CR2032 I had forgotten all about that! I usually order the lithium coin cells from Amazon or eBay which is where I buy 6 packs (or larger) of the common lithium coin cells at very reasonable prices.

    So could you use a conductive glue to mount leads if you didn't have a socket? I think I ordered some of that awhile back from that American Surplus & whatever mail order seller...

    I found these at Amazon, 10 for $5.81 with free shipping (not Prime.) Many of the ones listed there are PCB mount or with flimsy leads while these have solder tabs on the top. I guess you could just epoxy the holder to the old battery.



    https://www.amazon.com/uxcell-CR2032.../dp/B00GYW39KG

    HELPFUL HINT: When using a glue that doesn't set immediately and has to be held in place I've been using the 5 Second Fix which is cured by the UV LED on one end of the dispenser. It does not bond to all materials but you usually find that out right away (my first project was repairing an $8 rubbery plastic 13 quart trashcan... it does not bond to that kind of plastic so I went back to the Gorilla Clear Repair Tape I had been using before eventually recycling it.)

    Before I learned about the 5 Second Fix I used a similar trick but with a hot melt glue gun. 2 years ago I wanted to add an oak threshold to the side door on my garage to keep out rats which were getting in through the 3/4" gap between the door sweep and the smooth concrete slab.

    Not having the tools or desire to do it the proper way with a Hilti gun I heated up the smooth concrete slab a little bit with a hot air gun and then secured the threshold in place alternating dabs of hot melt glue and silicone. It is still attached securely and when it eventually comes loose I will use the same method to glue it down again.

    screenshot_2017-11-03-20-54-35_20171103205557945.jpg

    Steve A.

  7. #7
    Senior Member Enzo's Avatar
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    I buy them from Mouser or Digikey.

    I would never rely on "conductive glue" for electrical circuit. Soldered wires for me. The only place I would consider conductive glue would be a situation where I want static electricity shunted to chassis.
    Education is what you're left with after you have forgotten what you have learned.

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    Supporting Member Jazz P Bass's Avatar
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    By definition, EEPROM chips do not need to be powered all of the time.
    I do not see a 'battery' for the EEPROM.

    Here is the ME-20 & the EEPROM IC datasheet.

    ME-20.zip

    HN58X2408FPIE.pdf
    mozwell and g1 like this.

  9. #9
    Senior Member mozwell's Avatar
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    I am not familiar with this unit, but....

    There seems to be an internal 6x AA battery pack, presumably on connector CN3
    There are two EEproms, with I2C serial bus connection. These don't need a battery to keep their memory.
    Page 2 of the service notes says "user memory is in EEPROM IC8, moving user memory to another unit can be done by moving IC8 to the new unit, but is not recommended".
    There appear to be no button cells for memory backup in this unit.
    It is possible IC8 is bad, or maybe the serial bus is not working correctly. Easy enough to change IC8 & see how you go.
    IC8 is HN58X2408FPIE, 8 pin 1Kx8 I2C serial EEPROM
    A quick check on Digikey gives many suitable alternatives which should be drop in, the pinout is standard across different manufacturers, try CAT24C08WI-GT3CT-ND

    Good luck
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