Repairing a Presonus 1810 with low input levels

[Awats]

I wasn't sure where to post this and it can be moved at needed, but I had the common problem of an 1810 interface where the input levels on 2-4 were low. I could crank up the input level knob and use them but they clearly had problems.

I stumbled on this Presonus forum thread and it fixed my issues:

https://answers.presonus.com/37560/inpu ... s-very-low
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In my case it was a hardware failure; bad capacitors. I fixed it by replacing them because PreSonus wouldn't help.

I was experiencing this issue too with my 1810c -- low input levels while also audibly clipping (but not registering on meters) at low volumes on instrument inputs 1 and 2 (using guitars, passive pickups, both single coil and humbuckers). I didn't recall this issue always being the case. I hadn't played guitar in a while, but recently got back into it and wanted to solve this problem once and for all.

In addition to the 1810c, I have a 26c. So I swapped that into my setup, and what do ya know, it sounded great! This suggested that there was a hardware failure on the 1810c. I documented the issue and opened a support request with PreSonus. They said, yeah, sounds like a hardware failure, but your device is out of warranty (it's around 3 years old). PreSonus will not repair it, provide repair advice, or schematics. Basically they said I was on my own, which was a real bummer because I thought PreSonus (Fender) was classier than that.

Since I had nothing to lose by taking a peek inside the 1810c, I gave it a whirl. Upon doing so I immediately noticed that several capacitors had domed tops, which is indicative of failure. Specifically 8 capacitors, all of the same type, in two different sections of the board had the issue. The culprit caps:

C9A, C9B, C9C, C9D are marked with 1440
C9E, C9F, C9G, C9H are marked with 1448
(Marked with red arrows in picture)

Specs:

CapXon brand, GS series
220uf 25v - Polar, Aluminum electrolytic
~6.5mm diameter
~11.5mm height (excluding the domed tops lols)
2.5mm lead spacing
I think these have a ripple current of 310mA at 120 Hz based on the CapXon catalog, but I'm not certain.


These 5 caps have the same values as above, but were not visibly bad:

C90, C92, C93, C96
C146 (Might be marked C148. Hard to see in my pics. It's in the back right corner area next to C13 and close to the DC jack)
(Marked with green arrows in picture)

Image of capacitor locations: https://imgur.com/a/zNIrNoY


I'm no electrical engineer, but I do dabble in electronics so I decided to try the repair. Here are the replacement caps I sourced:

https://www.digikey.com/en/products/det ... 11/3567625

I think these are a suitable upgraded replacements, but if there's someone truly in the know, please post.

I carefully replaced only the visibly domed 8 capacitors. There were 5 more of the same type and value that seemed to be related to some other non-audio input/output functionality (guessing) that I left alone.

To my delight, the repair fixed the issue! My guitar tone is sooo much better now, and the input levels are great. If clipping does occur, it's registered on the meters and it tracks with the input gain being cranked too far, which is exactly what one would expect.

Hope this might be helpful to other people!
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Thanks to Dave Daverson for the above fix. Cost me $4.00 in caps!

Note: None of my caps were bulged or any other indication they were bad. They looked fine. I did keep track of where I took them from to try and isolate the section but accidentally mixed them up. All I can say is that out of the 13, 7 were bad (open or low capacitance.)

Awats

[Elysium.NZ]

Rubycon is a respected name in caps. They will be much better than the originals.

[Starship Krupa]

Rubycon is a respected name in caps. They will be much better than the originals.

They should be great and last until the unit falls apart.

My brand preference for low voltage electrolytics is Nichicon or Panasonic.