Sunday, October 30, 2016

Sony Kanji Video Titler XV-T33F and XV-T55F - part 1

As our MSX and video production series showed, Sony made a lot of video edit gear based in MSX technology. We already wrote about XV-T550, XV-J550, XV-J770, XV-J777 and XV-J555. The only one that wasn't based in MSX was the XV-T600.

Sony Kanji Video Titler XV-T55F

The Japanese Wikipedia have a list with some machines that they thought was MSX based. This list is very good, every machine in there is MSX based by this blog definition:

特にビデオタイトラーでは、ソニーのXV-J550/J770/T55Fシリーズや松下電器産業のVW-KT300などの家庭用タイトラーのハードウェア 構成は明らかにMSXを応用・流用したものである。ただし、これらの機種では基本はMSXシステムをベースとしていても独自の実装がなされており、特に BIOSなどは大幅に簡略化されMSXとしての機能は望めないなど、簡単な加工程度では汎用のMSXシステムとして使うことは不可能である。それらの MSXベースのタイトラーは安価なビデオタイトラーとしてはかなり普及していた時期があり、一時期は企業VPや解説ビデオやインディーズAVなどの小規模 なビデオ関連の作品などにはMSXの漢字ROMフォントとまったく同じフォントを用いたテロップを多く見かけることが出来た。これらのビデオ作品は一部で は2009年現在でも流通している。

In that list there is still one Sony Video Titler that we didn't verified, the Sony XV-T55F. Being in the list is enough to buy this titler. But that's not all, you don't need to be a very perceptive person to see the likeness of XV-T33F and XV-T55F:

Two Sony Video Titlers, XV-T55F at left and XV-T33F at right

Yes, they have the same form factor. So, I had no choice but buy a XV-T33F. Until now, all the titlers were targeted to the home-pro/semi-professional market, this ones are for the home market, as we can see in the XV-T33F box:

See? You can put text and
drawings over your home

Or in XV-T55F's manual:

Even a child can use it!

The XV-J555 is a departure from design of other Sony Video Titlers, integrating in the same unit the titler, the mouse (replaced by a trackball) and the keyboard controller. The Sony XV-T33F brings the design innovation one step further, now all the interaction is done using a stylus. As they have almost the same external look, we can say the same about the Sony XV-T55F. For brevity, all the pictures below are of XV-T55F:

This is the Sony Kanji Video Titler XV-T55F,
at the background you can see the box of XV-T33F

There are only a few buttons at left and right.
Most of user interaction needs to be done using
the included stylus.

At bottom you can see the battery compartment and the
"rails" to fix a video titler operation's cheat sheet.

At back of this unit we have a place to store the stylus.

The cheat sheet is somewhere in my
house. But while I can't find it,
you can see the cheat sheet's place
and the stylus storage in this picture
from XV-T55F manual.

Nothing amazing here, but maybe the serial
number could be useful for someone.

I was not able to take good pictures of the video inputs and outputs. The Sony XV-T55F have RCA video and S-Video connectors. One set for input and one ofr output. There is no audio inputs or outputs in this unit. You can see this a bit better in the manual:

The video input goes to the
connectors at left, the output
in the connectors at right.
Sound is ignored by this Titler,
in the picture it goes directly
from camera to VCR.

For completeness sake, this is my bad photo of the video inputs.

And this one is the bad picture
of the video outputs and the
power cord.

While the integrated "tablet" is a new thing for Sony Video Titlers, this blog already have a post about other Video Titler with a similar look, the Victor JX-T500. And this is not good news: the JX-T500 isn't MSX based.

What's inside the Sony XV-T55F?

The XV-T55F case is easy to open, you only need to take care with the few wires connecting the boards that are in the lower half, to the buttons and tablet surface, in the upper half.

The  two boards design. At the left side,
the mainboard and, at right, the superimpose module
(pick this name from XV-T33F's Service Manual)

As usual, we don't spend to many time with the video board. In the XV-T33F's Service Manual, the board is called "superimpose module", so we'll use this name here.

The superimpose module board.
I don't see anything great
about it. It's connected to
the mainboard and to the two
small side boards where the
video connectors (RCA and
S-Video) are located.

Now is time to check the mainboard. Let's remember what makes a MSX: Z80 processor, video processor compatible with TMS9928, at least 16KB of VRAM and 8KB of RAM, MSX BIOS and an equivalent of Intel 8255 PPI and GI AY-3-8910, usually those last two items and some additional logic are embedded in a MSX-Engine or MSX-System custom IC. In our "MSX based" checklist the MSX BIOS isn't a need, but the machine needs to be able to run it.

The main board. Here the fun begins. The V9938 is easily
spotted at right and the Zilog logo in the QFP located
at top-center shows to us where is the Z80.

Four Texas TMS4464 DRAMs,
each one with 64K x 4 bits,
totalizing 128KB of VRAM to
be used by the Yamaha V9938
VDP. It's interesting to notice
that this VDP was made in the
35th week of 1991.

A quick glimpse in the mainboard  shows two items from our checklist: the Yamaha V9938 VDP (the same of MSX2) at the right side and the Z80 CPU at the top-center. The V9938 with a 128KB VRAM are good signs for a MSX2 compatible machine. The ICs at left are ROMs and RAMs which can contain an MSX compatible software, which is a good sign, too.

ROM and RAM ICs, from top to bottom:
Fujitsu MB834000B - 512KB Mask-ROM;
SONY LH537507 - ????KB Mask-ROM;
Texas TMS48C128DJ - 128KB DRAM;
NEC D431000AGW - 128KB SRAM;

A close look on these ICs shows two ROMs and three different RAMs. There is a 512KB ROM from Fujitsu, which we guess houses the Video Titler Program ROM and a bigger one, with 42 pins, from Sony. I didn't found any doc with the size of this ROM, but the other ROMs with 42 pins  that I found are huge, with several Megabytes. I suppose this IC is where the Kanji fonts are located, they need a lot of space.

The three RAM ICs are two SRAMs and one DRAM. The DRAM have 128KB and is the Main RAM of this Video Titler. I don't know why there are two separated SRAM. Those ICs saves the titles and drawings created by the user and are backed by the AA batteries. I guess the smaller of those SRAMs are backed by another power source and can survive the battery change process.

At top, the Zilog Z84C0008 CPU;
at middle-center a big custom
gate-array from Sony and at bottom
a small buzzer.

The Z80 CPU is a Z840008 from Zilog. I don't know in which frequency it runs in this titler but it's able to run at 8MHz. It seems the late video titlers needs a faster CPU than the traditional Z80@3.57MHz. In the Victor JX-T800 and in Panasonic VW-KT300 we have the Z80 it running at 6MHz. The Victor JX-T500 is more radical and the Z80 was replaced by a processor from the Motorola 68k family.

While the other Sony Kanji Video Titlers uses the Yamaha S1985 (MSX-System II) to provides the PPI, PSG and all slot handling logic, the XV-T55F have a big custom gate-array with 120 pins, the MB620839 from Sony.

Again, we already saw the same approach in Panasonic VW-KT300 and Victor JX-T800. We can only know if these custom gate-arrays really implements the MSX architecture finding the documentation (almost impossible) or reading the ROMs and search the code to initialize and access the MSX hardware, like the slot handling, configure PPI ports, mute the PSG, etc.

In the VW-KT300 we saw the initialization code inside the Video Titler Program ROM and confirmed that it can run an unmodified MSX BIOS. These tests still needs to be done in JX-T800 and, now, in XV-T55F. I marked the Victor JX-T800 as MSX based, but now I am rethinking about that. Until the ROM was read we can't really say anything about the machine itself.

Next post we'll look the XV-T33F internals and disassembly its ROMs which are already dumped and available at HansO's site.

EDIT 2016-11-01: Fixed the correct frequency of Z80 in Panasonic's and Victor's video titlers. In the first version of this post it was published as "XMHz".