Sustainor 100 Bypass Failure

Discuss troubleshooting and repair.
Posts: 25
Joined: Mon Sep 06, 2021 3:49 pm

Sustainor 100 Bypass Failure

Post by dansgrandpapa »

Hi All,
Model: Sustainor 100
Purchase Date: 8/21
Condition: Online used
Issue: Bypass will not pop all the way out back to processed signal. Bypass LED not working in Bypass Mode. Rhythm Vol very quirky.

I was fortunate enough to find a hand made schematic on the web. Actually, very nicely done!
Tested LED location for voltage under power and it was looking like a dead LED.
Replaced LED and cleaned 20 or so years of neglect.
Turns out Bypass Mode REQUIRES the load of the LED to work right I think.
It sort of looked that way from the schematic also.
Upon re-ignition and to my delight, Bypass pops in and out, Led works and Rhythm Vol works too!

I run this one as #2 in a series of 2 with looped in SRD EQ's, into a Stereo Chorus and then Stereo Echo.
That goes into the returns of my XP100a with the cabinet split 4 feet or so. Clean 2 is just GLORIOUS!

Hope someone can use this!
If you guys see an error let me know, I'm new to SRD gear!

All The Best,
Posts: 33
Joined: Tue Apr 13, 2021 4:31 pm

Re: Sustainor 100 Bypass Failure

Post by Inventive »

Excellent trouble shooting. Thank you for posting.