RE: K2600RS Blue Screen but power and clock crystals good

I'm happy to report that I have recapped the power supply in my K2600RS and
now it boots up very quickly, within just a few seconds now.
 
About the "power_good" line in the startup circuit, it looks at unregulated
DC off the rectifier, so any increase in ripple will result in negative
pulse train at 120Hz in the POWER_GOOD line, preventing the unit from
initializing.
 
 



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During additional testing, I discovered the Power_Good line was pulsing
negative at 120 Hz. I traced back the sample to a unregulated DC rectifier.
Pulling that line high caused the K2600 to boot up.
I think it's dried out capacitors. So I'm replacing all capacitors in the
power supply. The large one, 33,000uF, is reading 21,000 on a GenRad
Digi-bridge.


[MW]  Today, I came into the studio and the display info was gone and only
the
blue seen backlight was visible.

If I power down and power up, after a delay, I hear the hard drive spin up
and head seeking, but the display remains blue/blank.