Post for Philmooo re MB-1 not used for 15 years

[rnolan]

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!

[Peter H. Boer]

Indeed sounds like a dead battery.

the upgrade to V2.05 software also included some small hardware adjustments.
The tube stage is very powerful and can go from clean to grit to real distortion sounds, the parallel SS stage obviously is always clean.
The 2 stage being parallel means you can distort the ..ll out of your bass, then mix in clean from the SS to retain the punch in the fundament. 

[Harley Hexxe]

Indeed sounds like a dead battery.

the upgrade to V2.05 software also included some small hardware adjustments.
The tube stage is very powerful and can go from clean to grit to real distortion sounds, the parallel SS stage obviously is always clean.
The 2 stage being parallel means you can distort the ..ll out of your bass, then mix in clean from the SS to retain the punch in the fundament. 

Well that's good to know
Thanks for posting that Peter

[rnolan]

Hey Peter, do you have the upgrade/spec sheet for the 2.05 EPROM upgrade ???  And/Or do you remember what the hardware adjustments are ??  :wave:

[Peter H. Boer]

Hey Peter, do you have the upgrade/spec sheet for the 2.05 EPROM upgrade ???  And/Or do you remember what the hardware adjustments are ??  :wave:

I uploaded what I have to the Vault (page 4)

http://adadepot.com/index.php?topic=148.45

[rnolan]

Cool, thanks Peter.