Hi all,
I had a lot of trouble with my TDS-520A, another one gone because of all the electrolytic juice destroying tracks.
I finally made it through by checking thousands and thousands of traces, and fixed about 30 dead traces all over the 2 boards, took me a couple of weeks (I know, why... because why not!).
Anyways, because this post is one of the top results in Google and as an EEVBlog afficionado and member, I wanted to help the community and share some of my work for anyone who would want to go through the same repair excise.
1) First finding: The original Service Manual sadly does NOT include any schematic, HOWEVER, the Service Manual for the original TDS520 Volume II has them, and it is an almost perfect identical match. Just be careful, some pages have a duplication (RAM for example) where both form factors are in the schematic, just make a note of which module yours has and discard the other half. The Service Manual is also known as "070-8313-00", for your Google search.
2) There were SO many ICs over so many pages that I started taking note of which IC corresponded to which section of the Service Manual, and has proven to be very useful, that's what I mainly wanted to share. Helped tremendously identifying and tracing.
Hope this will help womeon!
Cheers