Tuesday, July 5, 2016

Victor Video Titler JX-T800 - part 1

In last post we saw the Victor JX-T500. It's a video titler that uses the Yamaha V9958 video processor, the same of the MSX2+, but it's not a MSX. That was the first time in this blog that we saw a machine built in the  80s or 90s using the video chips designed and built by ASCII and Yamaha for MSX computers but without being a MSX based appliance.

But that is not enough to make us throw the towel. It's self evident that Victor/JVC did used knowledge acquired with their MSX2 computers to create the JX-T500 video titler. And, existing other titler models from Victor, there is a good chance that some of those models are in transitional state, not only using the MSX custom LSIs, but still being a MSX based appliance.

So, this is our new try with a Victor/JVC appliance: the JX-T800.

Victor Video Titler JX-T800

Victor JX-T800

After the analysis of JX-T500, the JX-T800's design is a bit boring. The big drawing surface, which is the highlight of JX-T500, is not there in JX-T800. Nor the many painting tools. But there are many buttons, levers, controls and a very small drawing surface were you can use a stylus to draw the character who will be put on screen.

Top view of JX-T800: a lot of buttons

The small drawing area and, at right, the stylus

The stylus is branded "JVC"

The rear view, with A/V inputs and outputs, and the power cord

The two A/V inputs. There are connectors for S-Video and RCA

The "Recording" output at left and "Monitor" output at right.
The switch selects the output's color mode between B&W and Color

The Victor JX-T500's opening left a bitter taste in the mouth. Let's see if the JX-T800 removes this taste and we can end this post revealing a new hidden MSX.

What's inside Victor JX-T800?

The JX-T800 opens in two halves. The top half have all the control boards, which is not a surprise: all the controls are on top of this video titler. The bottom half have the power supply, the video board and, below the video board, the digital board.

Victor JX-T800 upper half

The bottom half, with the power supply and the video board

If you have a good memory, the JX-T800's digital board looks like the main board of Panasonic VW-KT300. If you don't have a good memory, you can see the two boards side by side:

Victor JX-T800 digital board. Panasonic VW-KT300 digital board.
(this picture is from TabaLabs)

As you can see, these two boards are very similar. IMHO, one board is a derivative work of the other. At first glance this makes no sense since Panasonic and Victor are two different companies. However, the "derivative work" thesis isn't so crazy if we remember that, when the JX-T800 was released, the Victor was part of Matsushita group.

But we can't be fooled by appearances and speculations, this time we need to verify if this machine is really MSX based, so let's begin the compliance check list!

Those with good eyes probably already spotted the VDP Yamaha V9958 and the VRAM ICs in the board, we begin with luck.

4 x Sharp LH2464 with 32KB each and
the Yamaha V9958 video processor

Next we have 64KB of RAM and 32KB of SRAM backed by battery, to store your title sequences.

Battery, 2 x Sharp LH2464 with 32KB RAM each and
the SRAM NEC D43256AC with 32KB

So, in our MSX checklist we already have the 64KB RAM and the Yamaha V9958 with 128KB of VRAM. The list can be improved with the ROM chips: the two Fujitsu MaskROMs are probably the Kanji-ROM. If this machine is MSX based, the last ROM, with 256KB, can be the BIOS+SUBROM+CustomSoftware (like the Sony titlers) or a big custom software (like the VW-KT300).

ROMs from top to botton: one Sharp LH532H0S with 256KB and
two Fujitsu MB834200A with 512KB each.

The next item on our checklist is the MSX-Engine, and inside Victor JX-T800 we have a NEC gate-array that can be the MSX-Engine equivalent. To finish our checklist of hardware components there is only one thing missing.

The NEC gate-array

The main processor! And this time it's the right one! We have a CPU from NEC, compatible with Z80, running at 6MHz! This is another sign that the likeness between Victor JX-T800 and Panasonic VW-KT300 isn't a design coincidence: both titlers are using a high speed Z80.

By other side, if you don't like my thesis of  "derivative work", it's easy to remember that Victor and Panasonic are the only companies that officially designed and sold MSX computers with turbo mode: HC-95/90 from Victor and A1FX/WX/WSX from Panasonic.

NEC D70008AC-6 - A Z80 compatible running at 6MHz

Wow! Victor JX-T800 "completes" our  MSX2+ checklist. The "completes" is between quotes because we don't know yet what this NEC gate-array is. We presume, by previous experience, that it is some kind of MSX-Engine, but we don't know yet if this is true. And even if it is, we still can't give warranties that this video titler is MSX based. To really clear the doubts, we need to dump the ROMs.

For now, to sweeten my mouth after the disappointment with JX-T500, I will keep the Victor JX-T800 in the category of "MSX based". But the real confirmation only comes after the ROM dump, and this dump will be the subject of other post.