Worst Symetrix 528E I have seen 

For sure the power supply caps and all the 47uF/100 electrolytic. The 47uF bipolar may or may not be bad but I can almost guarantee you need to change all the 4.7uF SMD caps. Don't forget the two in front of the voltage regulators.. They go bad and make the whole thing oscillate around 10MHz which puts some strange noises in the audio. You can probably get away with not changing the 10uF SMD caps.

@@AERVBlog I'll open one of these things up and take a look and see if it's something I'd like to tackle :) Thanks for all the info!

First off what do they mean upgraded caps? Most people will change out the power supply caps and some or all of the through hole caps. That is nice but many of the problems arise from the bad 4.7uF surface mount capacitors. There are 14 of them and they all need to be changed. The ones across the + and - 15Volt supplies are particularly suspect. They can cause the whole unit to oscillate anywhere from 400KHz to 10MHz. If you don't know what you are looking for you can easily miss that and very weird things will happen to the sound. I would ask the seller if those SMD caps had been changed out. If so I would say you would be good to go, for a reasonable price. I don't have any experience with the dbx 286 so I can't comment it that but think of it this way, Symetrix sold tons of these things and they are literally in almost every radio station in the country. The only thing I would say though is stay away from the 1995 version. The op amps in the mic amp are a little noisy in my opinion. Those also have all through hole components, ie - not modern. Just leave the 528, not E version, alone. They are OK I guess but they don't hold a candle to the E versions. This is from my testing on distortion and linear tacking. Hope this helps and thanks for watching.

@@AERVBlog Thanks for the help i just purchased a brand new DBX 286s don't want to risk with this device

@@AERVBlog Thanks so much for this comment. I've got one of these on the healing bench that had very little output and it was real noisy so I replaced all the through hole caps and that got it mostly working, passing signal okay, except for a small bit of noise which turns out to be a 750khz oscillation across the whole unit, just a small one, like about 126mV pk-pk. So I turned to the internet and came across your channel. (Great content btw!) I haven't touched the SMD caps yet, but after reading this, I bet dollars to doughnuts that is my problem. Thanks for the knowledge.

​@@LaughingBuffaloesyes. It sounds like the 4.7uF 35V BiPolar caps in front of the + & - voltage regulators are bad. Good catch. Let us know how it comes out.

i bought both for $160 the other day

You can't win. If you keep it on all the time the caps will go. If you don't use it the switches will fail. Up to 23 years is still a great run though and I haven't found anything better.

@@AERVBlog I have so much old gear that I am trying to keep alive. My sound console keeps me busy Mackie d8b and it is sometimes a true nightmare. Someone who can not afford to buy new gear I am always learning repairing and electronics. Thank you for videos like this. Really helps us non professionals.

I have 2. The white and black one is a Vici meter. The output is serial, RS232, using a serial to USB cable. The software is 3rd party since the thing that comes with the meter won't work on windows 10. The yellow and black one is a Peak Meter with a USB output.