27 Feb
2002
27 Feb
'02
7:45 a.m.
Indeed, my boards are P/N 15532001-01. Mine doesn't have a 7556-00, but a
7358-00. The 48 pin ASIC is the same. U8 is a 6-Unit 320mA Transistor
Array with Clamp Diode and Strobe, and probably most of it is used in the
stepper motor driver. They're probably using 1 of the channels to pull down
the head solenoid because of it's current capability. The silly
Mitsubishians have a dimensional drawing of the part, but no actual
datasheet.
Would it be possible to get a copy of the schematics? Either a high
quality Xerox, or scan to PDF or something?
--John
-----Original Message-----
From: owner-classiccmp(a)classiccmp.org
[mailto:owner-classiccmp@classiccmp.org]On Behalf Of Tony Duell
Sent: Wednesday, February 27, 2002 15:40 PM
To: classiccmp(a)classiccmp.org
Subject: Re: Teac FD-55B Floppy Oddity
Thanks! Perhaps this will be a start towards debugging it.
I do know that
the head load solenoid is on a 2x3 connector, and
uses the two end pins.
Three of the remaining 4 pins go to the home position opto
sensor, and the 4
Sounds like it might be the same drive. It was late when I posted last
night, and I didn't notice that the track 00 sensor uses pins 4,5,6 of J4
also. Pins 1 and 2 of J4 go to the load solenoid.
The schematic has 'P/N 15532001-XX' printed on it. Can you find that
number on the PCB? It uses 2 ASICs, 1922-00 (mostly digital circuitry,
looks to have about 48 pins) and 7556-00 (analoge read/write circuitry,
looks to have 30 pins).
-tony