Help 18 Watt Trem build

18watt-specific Tech Talk - Building, Fixing, Parts, Mods...

Moderators: CurtissRobin, colossal, zaphod_phil, Daviedawg, Graydon

Post Reply
User avatar
sdlogan9
Unrated
Posts: 1
Joined: Sun 04/29/07 2:00 am
Location: Unknown

Help 18 Watt Trem build

Post by sdlogan9 »

Hey Guys I need an expert here.

The trem seems to be bleeding into the cuircit - when I plug in the footswitch I get a ticking sound - when I engage the footswitch I get a constant loud beeeeeeeeeeeeeeeeeeeeeeeeeeeeeeppppppppppp

I am building this off of the Revision 5 1/28/2021 wiring diagram from mojo

I am worried somthing is wrong in the layout :D However I am human and could be overlooking something with my own work.

Please Help!!!!!!!
You do not have the required permissions to view the files attached to this post.
0 x

User avatar
JMPGuitars
Super Duper Admin
Super Duper Admin
Posts: 3955
Joined: Tue 09/18/12 8:00 pm
Location: South Central, MA
Contact:

Re: Help 18 Watt Trem build

Post by JMPGuitars »

Hi,

Unfortunately Mojo build docs are notoriously troublesome. The first step is to highlighter verify BOTH the SCHEMATIC and the layout. Make sure every component value, and every connection match both documents.

Once that's complete, take a look in the downloads section and use the classic voltage chart to measure your voltages, then post them here.

One of our other members more familiar with the specifics of their doc troubles may chime in as well.

Thanks,
Josh
0 x
'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright

Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info


Web Design: DolceVittoria.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale

brewerboy
Unrated
Posts: 1
Joined: Sun 12/06/20 5:43 pm

Re: Help 18 Watt Trem build

Post by brewerboy »

On my Mojo Classic 18 (finished ~2021-03), the Plain channel is just fine. My son uses it as his "daily driver".
Unfortunately, the Tremolo channel has issues, and is unusable.

Actually, Mojo build documentation is limited to:
* a schematic
* a build diagram
I had to request a diagram with voltages. Luckily, I have a little experience with a soldering iron, and Attention to Detail. But for anyone else looking to LEARN, at least SOME kind of Assembly guide would be appreciated.

Thanks for this answer, @JMPGuitars. I found the voltage sheet after a bit of hunting.
Right off the bat I have 607V AC input to the rectifier, and 357 DC output, leaving only 325V DC output from the capacitor. I'll fill out the rest tomorrow, & post.

Yes, yes; mea culpa. I'll build one of yours next.

Kind regards,
Drew
1 x

Post Reply