ReinardSynth#15 Lexicon PCM90 Repair: no boot? Encoders not working?

Ever had one of those projects you cannot solve and are working on and off on? Here is one I had: Repairing a non-booting Lexicon PCM90...
Finding the reason it did not boot was ... convoluted to say the least. Solved it, but then new problems popped up.
In the end I have a fully working PCM90, but I did learn something which this whole episode is about. Hopefully it is of use to you.
This video does assume basic knowledge about how microprocessor based solutions work. It does get rather technical... sorry...
Links:
- PCM90 Service Manual: elektrotanya.com/lexicon_pcm-...
- V1.01 Firmware: matrix-productions.com.au/down...
- V1.0 Firmware: download/683...[0]=AZXKSeDY5Z-cVswp8Xt0_2ojLpXbunZl1GP6oeXKtfHXs8qpbISt0pXKZmzYH1AeezrP8NpeuxDjEqoK5R2hg9ab0mRY8eu_LU7BFQpEebsCT1oHnTt7BwTjg_LAMq7OswUsX1HY0l_tCRU0f99uvH4SXyM3PW2zSjmG1PI3uOPhdQ&__tn__=H-R
EDIT: Noticed that a (dummy) picture of an eprom in my TL866 is missing at 03:08 and 08:04... uploading an update would remove the views and comments; so I let it be...
Tools used:
- Steinberg UR22mkII + Audio technica 2020 for voiceover,
- Olympus E-M10 as video camera (older HD video segments), Sony ZV-e10 as video camera (for 4K segments)
- Manfrotto Magic Arm
- Editing: iMovie (Easy bits) + Davinci Resolve (difficult bits)

[@bandita84]

what a pain with this old stuff. I will also repair everything I really want, but here it could be a physical impact on the device.. congratulations on your success

[@andrearossi7863]

This is very helpful, thank you so much for sharing!

[@aly.3921]

subscribed...amazing work...really informative...please keep up the great work!!!

[@christianvictor827]

That was so so informative! ❤

[@ToumalRakesh]

Last time I was this early, Uli hadn't made a clone of this yet :P

[@Davidmhjr]

The ADJUST encoder on my beloved PCM90 isn't tracking correctly anymore and I would love to find a replacement somewhere... Or fix this one?

[@user-gl6tt6em9u]

Still could not get the firmware due to the offline webpage? could I get a new address to download it? Thanx!