I am recovering sony F1 type audio (PCM and ECC in the video image) from 
some VHS tapes (ep speed 6 hr per tape)  - it was actually recorded with 
a Toshiba version.
I have the manual for the Sony 601-esd and I think is says the boobie 
lights (Red, FlashRed, FlashGreen, FlashGreen, SteadyGreen) is a logical 
procession from poor signal to good signal.
Additionally there is a tracking indicator (bar graph moving to the right)

I can see from the schematic the LED's are driven from the decoding 
logic (didn't really need a schematic for that one).

However, I an not find out at which point errors are still being 
corrected (apparently a few red flashes are fine) and at what point I 
can not count on the data.
I am recovering through the spdif -> PC.

I am hoping there there is a audio archivists list with somebody who 
used these 30 years ago and thought to ask Sony exactly what was being 
measured with the lights.

P.S. I found the Sony 601-esd encoder/decoder is not a good match with 
most later model VCR's and ep tapes. (the data on the back of a VCR 
switch disappeared years ago).

John Gledhill
905 881 2733
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