Hey Phillip, I see you've joined the depot, welcome. I'll start a post for you in the MB-1 threads so other can chime in with any ideas.
Sounds like the battery is dead (from what you describe). You can source the battery mod from (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm) if you want or you can buy a holder and battery from an electronics supplier/shop. The replacements use a CR2032 3v lithium button battery. The bit to watch out for is that the soldering lugs on the holder line up with the MB-1 circuit board.
You could replace the tubes although they may be fine, the MB-1 factory patches are mostly SS so don't use the tubes much. Moreover, the tubes don't get pushed for distortion in the MB-1 like they do in the guitar preamps. Also the original tubes (if that's what is in your MB-1) lasted allot longer than new tubes as they pumped them longer in those days and achieved a better vacuum.
You could also update the EPROM, last MB-1 was v2.05 and the MDRT replace transformer is a great upgrade, I have them in both my MB-1s, really opens the dynamics of the unit.
Philmooo wrote:Hello, I found your forum page from a youtube video I watched by Blackbridge Sound when I was trying to troubleshoot my MB-1... I fired up my bass gear for the first time in probably 15 years, at first glance it seemed promising but there was no sound produced.I realised the preamp was acting a bit off... It used to go through the tube warmup and would be ready to go. It currently displays 1.21 and then sequences through 1-?? I suspect the internal battery is dead but I don't know if there are any other things I should look at? To my knowledge the tubes have never been replaced. Do you still offer the replaceable battery tray mod? Thanks!
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Topic: Post for Philmooo re MB-1 not used for 15 years (Read 177 times)
