TCA240 pinout and a little data

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Mon Feb 23 17:49:27 2004

>
> On Sat, 2004-02-21 at 22:56, Tony Duell wrote:
> > Jules Richardson (IIRC) was asking about this chip to repair a classic
> > computer peripheral (so it is on-topic)...
> >
> > I can't find it in a databook, but I've found a circuit that uses it --
> > the 'Head Amplifier Playback' module (board P50) in a Philips VR2020 VCR
> > [1].It seems to contain 8 NPN transistors and nothing else (at least the
> > schematic of that board shows the internals of the IC as 8 transistors
> > only) and consists of 2 identical sections.

Oops, I forgot the footnote. What I was going to say was :

[1] This is a V2000 machine, not VHS. It has some lovely design features,
like dynamic track following (the video heads are mounted on piezo
crystals, and are deflected to follow the video tracks on the tape, much
as a hard disk head is kept on-track. This gives a noise-free still
frame, for example.

There are 5 motors, and very few other mechanical parts in the machine.
The only 'rubber part' is the pinch roller. Direct drive to the capstan,
drum, and each of the spools (that's 4 of the motors -- the fifth is for
tape threading). Backtension is applied by passing a small current
through the supply spool motor.

Oh, and the electronics is on a lot of plug-in cards. The service manual
(I have said manual for the VR2020 and the slightly better VR2022, along
with 2 of the latter machines) has a section for 'units' (tuner, RF
modulator, backplane, etc) and as section for 'boards' (all the plug-in
modules).

>
> That's brilliant, thanks. I assumed that whatever was going on in there
> was coupled somehow, so treating it as two seperate arrays should make

It's shown as 2 separate sections in this schematic. There may be
caveats, like one of the pins connects to the substrate and must always be
more +ve / more -ve than all the others, but this shouldn't cause
problems in usderstanding the circuit.

-tony
Received on Mon Feb 23 2004 - 17:49:27 GMT