Does recapping work? (Patreon preview) 

Here's some recent workshop footage on a Yamaha Multitracker MT120 - I intended it as an exclusive patreon video, but since the topic is so relevant to folks with portastudio audio issues I've made it public as an opportunity to upsell my Patreon (link below).
While replacing audio path electrolytic capacitors is NOT a silver bullet for EVERY audio problem, in my experience 4/5 audio problems I fix on multitrack cassette recorders can be at least partly explained by replacing these parts.
This clip demonstrates several examples where replacing audio path electrolytic capacitors was helpful;- The right side of the stereo buss didn't pass signal at all; the output from mixer channels 1 and 4 was attenuated compared to the output from the tape outs; the output from mixer channel 2 was too loud and distored.
It also includes one example where recapping didn't make any difference, because I mistook the change the master buss graphic EQ was making to meter readings for a capcitor issue.
You CAN dramatically reduce the number of caps you need to replace by diagnostic techniques such as using an oscilloscope or audio probe in conjunction with the schematic to figure out where the signal audio signal stops or changes, but often I replace audio caps for an entire stage or even a whole board in one go: This is because the time to install them is trivial compared to access/dissassembly time, and the cost or the caps themselves is trivial compared to how I value - and charge for - my time.
Since these components have a relatively short shelf life anyway, and most units I work on are 20-40 years old, nay replacement of electrolytic capcitors should contribute to the longevity fo the unit. Therefore, I don't agonise over finding the proverbial needle in the haystack with an ESR meter - I'm happy to replace a few healthy caps along with the leaky ones!
Just my approach, your milage may vary.
___________________________________________________________________________________
TETRAKAN - Fix & Use Tape Recorders
Overviews; tear-downs; repair vlogs; techniques; tutorials; demo recordings...
...covering every cassette multitrack recorder ever made!*
*(eventually)
/ tetrakan
TOOLS AND EQUIPMENT I USE;-
kit.co/Tetrakan
I post exclusive content on PATREON;-
/ tetrakan
DONATIONS are gratefully accepted via my BLOG, which also features written articles and FREE DOWNLOADS OF SERVICE MANUALS;-
tetrakansupermonobloc.home.blog/
I prefer to answer questions in the youtube comments where my answers can help more than one person, but if you need to share photos etc, you can message me via facebook.
/ tetrakan

Наука