9 Feb
2006
9 Feb
'06
4:35 p.m.
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