Date on STK7551 regulator?

[Tony Duell]

> 
> Tony,
> 
> The 7551/7552/7553 are all discontinued, but I believe the replacements are

That does not suprise me. The Epson TF20 floppy drive (which is where I 
came across it) must be at least 20 years old now.  Fortunately, all the 
chips on the cotnroller board are recognisable (some are almost certainly 
discontinued, but common -- rows of 74LSxx TTL, a Z80A, 8 off 4164 DRAMs, 
a 2716, a 765 disck controller, etc)

> part of the STK755-xxx series.  Here's the datasheet (in Japanese) for the
> 755-110, which outputs +12 and +5.

Where? Did you forget the URL?

The PSU board in the TF20 contains this hybrid, a bridge 
rectifier/smoothing capacitor (takes in 24V AC from a transfromer on the 
main chassis), a few smaller capactiors, 4 torroidal inductors (looks to 
be an energy storage inductor and a filter for each output), 2 of what 
look to be snubber networks (diode, resistor, small capacitor) and a 
couple more resistors and a zennr. The last makes me wonder if the output 
voltage of the 7551 can be set by external compoennts.

-tony