Lab Series L4 fix...

[Michael Allen]

Hello all,

I am working on a Lab Series L4 for a friend. Not sure what is wrong with it, so I'm starting from the ground up. Looks like someone tried to rewire some things so I"m not sure what's original.

Haven't been able to find any schem or layout for this particular model, though I've looked over the L5,7,9,11 schem and layout since they are similar. They're close but not identical (obviously) so it's hard to tell exactly what's correct.

Does anyone have a schem or layout for the L4. Even closeup chassis pics of the wiring connection in the power supply would be helpful.

Thanks,
Michael

[Enzo]

I guess I am the Lab Series guy this week.

The L4 preamp is below.  The power amp is the same as the L5 etc, and I had to scan it gray scale to see everything.  The layout also had to be gray scale and the files are several times the limit of this board.  SO I will post those in the Enzo gallery at www.ampix.org

[J M Fahey]

Not only "Lab Guy" !!! Those schematics are a real bonus to all us.
Thanks, Enzo. You and Teemu keep this place alive and kicking.

[Michael Allen]

Thanks Enzo,

I ended up getting it fixed and wired up right just by guessing at the differences between the L5 and L4. I redid all the original wiring around the power section, since there's that goofy switch and 120V output socket, and the 120V socket for the fan.

Thanks for these documents!