MP-1 Classic clean tone only possible battery issue

[frehley6986]

Bought a used MP1 Classic several years ago. The last time I tried using it I got no signal. I am getting signal but no tone except a pure clean sound. If I edit the program and pick a tube (brown) i get the distorted sound and anything else.
I'm guessing the battery is dead although it looks to have been changed before.

Do these require another battery or can the battery mod be done like i did with my MP-1?

If the batter is dead will there be no programs even the factory ones?

TIA

[rnolan]

I suspect the battery is the same as for MP1/2 (3v lithium e.g. CR2032).  In the MP2 the battery is mounted vertically, the MP1 is horizontal so they require slightly different battery holders, which is basically the battery mod, the original battery's had connectors soldered to the battery (you can buy 3v lithium batteries with the soldered lugs or install a battery holder (i.e. the battery mod)).  Factory presets are stored in the EPROM so are not affected by the battery.  Changed/stored patches/programs are stored in RAM which is kept alive (stored) by the battery, this is the battery's only job (as far as I know) and thus are lost when the battery either dies or is disconnected.

[MarshallJMP]

It has the same battery as the MP-2, so mounted vertically. Up to now I haven't found a battery holder for these. If the battery is dead you will get a bunch of error mesages on the display and it will count from 1 to 128. Users presets will be gone but the factory presets should still be there since these are stored in the eprom.

[frehley6986]

Is there a specific part number or battery that fits in there?

Also I'm gonna try a factory reset to see if my factory programs come back.
Is it possible the EPROM is bad?

[rnolan]

You need a 3v lithium battery, most common is a CR2032 button battery.Vertical holder - (https://www.ebay.com.au/itm/5x-CR2025-CR2032-3V-Button-Coin-Cell-Battery-Vertical-Socket-Holder-Box-Case/184279895404?hash=item2ae7f00d6c:g:i~0AAOSwHcxesTds).  Not sure why it has 3 lugs/connectors, you only need 2, also getting the right spacing for the PCB holes can be problematic, you probably need to bend the lugs to fit.
One with lugs attached - (https://www.jaycar.com.au/cr2032-vc-3v-pcb-mounting-lithium-coin-battery/p/SB1762).  This is what I used for one of my MP-2s, had to bend the lugs to get them to line up, again you only need 2 connectors (1 x +ve, 1 x -ve).
I haven't heard of anyone having a bad EPROM, I spose it's possible but unlikely.  A factory reset should load all the EPROM programs into RAM (user) which works while the unit is powered on.  IIRC you can switch between preset and user, well you can on MP-2 which the Classic is similar to (in some ways).  I think maybe Preset accesses the EPROM programs, user accesses the RAM and you can modify and save the patches.

[MarshallJMP]

Those holders won't work. The spacing of the pins is not correct for the classic/mp2. The correct battery is a BR-2325/VGN.
Don't think it's the eprom then you would also get an error.

[frehley6986]

Thank you i'm ordering a battery.

I had to factory reset it but the factory settings have been holding while it was unplugged. It hasn't been plugged in for maybe a year or twol