Friday, June 10, 2016

Panasonic Video Titler VW-KT300 - part 1

Matsushita was one of the first companies to join the consortium MSX (some say M is Matsushita) and, as Panasonic, was the one who released the latest official model of MSX (MSX Turbo R FS-A1GT). Between the beginning and the end of the standard, Panasonic (and National) launched many different models and MSX's peripherals. Even some models with AV capabilities, such as the National FS-5500:

National FS-5500's advertising in MSX Magazine 1986-01,
it's an amazing machine with AV capabilities, one or
two floppy disk drives and a trackball integrated in
keyboard. The downside is the amount of RAM, only 64KB.

Like Sony did before, Panasonic used their know-how in MSX and Video applications to build their own videotitler: The VW-KT300. This equipment is not totally unknown by MSX users; it had a full-page article on the MSX Magazine (but without the word "MSX" in the text):

First section of the article on news from Panasonic in
MSX Magazine 1990-03. As you can see, no "MSX" in this section

And, in an other article from 1990, the VW-KT300 is already identified as based on MSX technology:

Panasonic VW-KT300 in MSX Magazine 1990-04.
The same article lists Sony XV-J770 as MSX based.

It's no surprise that this Panasonic appliance is in Wikipedia's list of MSX based hardware (The text in red says "VW-KT300 from Matsushita Electric Industrial"):

"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。"

With that information, and some news and forums posts about XV-T550, I bought this machine, with the hope to easily boot it in MSX mode. The VW-KT300 was the first equipment that I bought in my search for hidden MSXs. It was not featured in the first post in this blog because:
  1. Other machines (Aucnet NIA-2001 and Pioneer UC-V102) have a lot more impact and
  2. The story of how I found this VW-KT300 is very boring: "I saw the name of this machine in an article in Wikipedia, I bid on an auction and won."
I bought it and, while waiting the package arrival from Japan, I began a more serious research about hidden MSX (which gave very good results). I expected to see something like the Sony XV-T550, with a full MSX BIOS, a known MSX engine and a nice cartridge slot to do some tests. When the package arrived and I put my hands on this machine, I found that I am not a good guesser.

But, even without meeting all my expectations, the machine is very interesting!

From outside it have a good design; with some inputs and outputs for video and sound, an IC card slot, a custom keyboard and a mouse.

Panasonic VW-KT300: a very clean visual in front panel,
polluted by a big colorful sticker.

Rear of VW-KT300, with many S-VIDEO and RCA connectors

The mouse is the Panasonic FS-JM1, the same that are sold for MSX computers:

The VW-KT300 mouse. The only place where you can see the MSX
logo without open the appliance.

All videotitler functions, besides the point and click, can be controlled using the small keyboard:

The control keyboard
(image from a Y!J auction. I'll change it when I (hopefully)
find where is my own keyboard)

In the front panel, we have the power button, the keyboard and mouse connectors, the IC card slot and S-video and RCA inputs. It seems that the IC cards were a common media for appliances in Japan:

As said in main text, the front panel have a power button,
power LED, keyboard and mouse connectors and IC card slot

The big sticker advertises the key features of VW-KT300.
The first line of japanese text says: "Easy and Beautiful
Kanji Titles - MACLORD Video Titler", the line below talks
about the font resolution, sample titles, characters per
screen, and transition effects. Finally we have the Input-2
connectors with S-Video and RCA

Input-1 connectors: S-VIDEO and RCA. Next the selector
for Black&White or Color output

The two sets of Output connectors. Both with S-Video and RCA

The knob to adjust the superimposer hue, then a power
outlet and the power cable connector

What is inside Panasonic VW-KT300?

When I opened the VW-KT300, I already did saw a few pictures of the mainboard on this site (in japanese) and knew that the cartridge slot was not there. But still thought that would be a MSX engine somewhere at PCB's other side and a full MSX BIOS would be waiting for me. However, as I said before, I am not a good guesser.

Half of the logic board. At top center, the NEC gate array;
at top right you can see a Z80B from Zilog.
The bottom row are the ROMs

The other half of logic board. At top left the VRAMs;
at picture's center, a CR2032 battery and an Yamaha V9958
(the chip with the heat sink). At bottom row we can see
more RAMs and the ROMs.

Talking about  the good stuff: the machine has an Yamaha V9958 with 128KB VRAM, a Z80B (faster than usual) as main processor, 64KB RAM  and many Kanji-ROMs from Panasonic's MSX equipment (computers, cartridges, printers, etc).

First we can see 64KB RAM (2 x MN41464A), then a Fujitsu
MB834200 512KB MaskROM (24-dot Kanji-Fonts), a 32KB SRAM
(Fujitsu 84256), the program ROM (FS-VA1) and another
Fujitsu 512KB MaskROM (now is a MB834000) identified in
the PCB's silk as "ROM Jisho", which means "Dictionary ROM".

After an empty IC placement there are two ROMs. The first
one is from FS-PK1 printer and the other one looks to be
the Kanji-Font of the A1FX MSX computer.

Excluding the RAMs and ROMs, the main ICs inside the VW-KT300 are:

  • Zilog Z0840006PSC: Z80 processor with 6.17Mhz clock
  • NEC D65042GD405: NEC gate array
  • Yamaha V9958: MSX2+ VDP

As we can see, no stock MSX engine in this list. But we know many MSX computers that doesn't have a engine from Yamaha or Toshiba, those machines have discrete components or a custom gate array to do the MSX engine's job,  the big NEC gate array is a good candidate to fill this role.

The NEC gate array

I took this device to Alexandre Tabajara's lab, so we can take a better look in this NEC IC and dump the program ROM. But that is a talk for our next post.

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