Uploaded October 2025 | Updated September 2026, 3 weeks ago
// This video is proudly sponsored by PCBWay! Whether you're a hobbyist or a professional, PCBWay offers you a wide range of high-quality services including PCB prototyping, PCB assembly, 3D printing, CNC machining, and injection molding. Thank you to Elaine Hu and the entire PCBWay team for their support! //
I wasn't expecting to make this video, but my computer editing monitor speakers just failed. Obviously that puts a spanner in the works regarding content creation.
In this video I completely strip down a non-working Presonus Eris 3.5 Generation 1 studio monitor and replace its failing electrolytic capacitors. The Eris 1 was not powering on. The stock caps were cheap, low-quality parts that had become faulty from heat. As one audiorepair forum user noted, the original ācap-topā capacitors in these monitors are āabsolute sh**eā and prone to failure
We desolder every bad capacitor and install high-quality replacements, then reassemble the speaker. After the swap, the monitor comes back to life.
Inspection & Teardown: Opened the active Eris 3.5 monitor and examined the circuit board. Bulging or corroded electrolytic capacitors were identified as the likely culprits.
Capacitor Replacement: All faulty low-grade capacitors are desoldered and replaced with premium new ones (same capacitance/voltage, premium bransd). Each component is matched for size and orientation to ensure a proper fit and performance but I do make a small mistake as you'll see in the video.
Testing & Verification: Each removed capacitor is tested with an ESR meter ā most old caps show high ESR or shorted electrolytes, confirming failure. After installing the new caps, I power up the speaker and test it; the power issues are resolved and the monitor works like new.
In our ESR measurements, several original caps were well out of spec. After the upgrade, the sound is fully restored and stable.
Incidentally, other Presonus users have observed similar problems. A PreSonus forum report describes one monitor only working when its 100ĀµF power cap was heated with a hairdryer ā cooling would cause white noise and shutdown. Thatās exactly the kind of intermittent failure heat causes in cheap electrolytics. By replacing all the weak capacitors with high-quality parts, we avoid this trap. The end result: a fully repaired Eris 3.5 monitor!
-- Supporting the Channel --
If you are minded to help with my Garage Studio Conversion Project this is where you can find the GoFundMe gofund.me/bb11d39a
Massive thanks to my amazing patrons. You can help me on my retro journey at patreon.com/markfixesstuff
For one-off support, please consider buying me a Coffee at ko-fi.com/markfixesstuff
- Downloads and Helpful Stuff -
You can download the Updated and corrected capacitor list HERE: markfixesstuff.com/presonus-eris-3-5-no-power-fix
#DIYAudio #SpeakerRepair #presonus
// This video is proudly sponsored by PCBWay! Whether you're a hobbyist or a professional, PCBWay offers you a wide range of high-quality services including PCB prototyping, PCB assembly, 3D printing, CNC machining, and injection molding. Thank you to Elaine Hu and the entire PCBWay team for their support! //
I wasn't expecting to make this video, but my computer editing monitor speakers just failed. Obviously that puts a spanner in the works regarding content creation.
In this video I completely strip down a non-working Presonus Eris 3.5 Generation 1 studio monitor and replace its failing electrolytic capacitors. The Eris 1 was not powering on. The stock caps were cheap, low-quality parts that had become faulty from heat. As one audiorepair forum user noted, the original ācap-topā capacitors in these monitors are āabsolute sh**eā and prone to failure
We desolder every bad capacitor and install high-quality replacements, then reassemble the speaker. After the swap, the monitor comes back to life.
Inspection & Teardown: Opened the active Eris 3.5 monitor and examined the circuit board. Bulging or corroded electrolytic capacitors were identified as the likely culprits.
Capacitor Replacement: All faulty low-grade capacitors are desoldered and replaced with premium new ones (same capacitance/voltage, premium bransd). Each component is matched for size and orientation to ensure a proper fit and performance but I do make a small mistake as you'll see in the video.
Testing & Verification: Each removed capacitor is tested with an ESR meter ā most old caps show high ESR or shorted electrolytes, confirming failure. After installing the new caps, I power up the speaker and test it; the power issues are resolved and the monitor works like new.
In our ESR measurements, several original caps were well out of spec. After the upgrade, the sound is fully restored and stable.
Incidentally, other Presonus users have observed similar problems. A PreSonus forum report describes one monitor only working when its 100ĀµF power cap was heated with a hairdryer ā cooling would cause white noise and shutdown. Thatās exactly the kind of intermittent failure heat causes in cheap electrolytics. By replacing all the weak capacitors with high-quality parts, we avoid this trap. The end result: a fully repaired Eris 3.5 monitor!
-- Supporting the Channel --
If you are minded to help with my Garage Studio Conversion Project this is where you can find the GoFundMe gofund.me/bb11d39a
Massive thanks to my amazing patrons. You can help me on my retro journey at patreon.com/markfixesstuff
For one-off support, please consider buying me a Coffee at ko-fi.com/markfixesstuff
- Downloads and Helpful Stuff -
You can download the Updated and corrected capacitor list HERE: markfixesstuff.com/presonus-eris-3-5-no-power-fix
#DIYAudio #SpeakerRepair #presonus
