[Coco] Re: the XRGB-2+ upscan converter

[Charlie]

Excellent news.

If enough coco fans buy this device, would you make a web page with pictures
showing what you had to change to make it work?

Charlie

<RJRTTY at aol.com> wrote in message
news:19e.28844cfe.2e5d47ef at aol.com...

>

>

> OK ladies and germs,

>

>      I have received the XRGB-2 converter from Pacific Game Tech

> LTD. based in Hong Kong and here is the story:

>

>      When I first opened the box and looked at the owners manual

> my heart sunk.  The thing was written in chinese or japanese or

> whatever.  I figured I was in for a tough time for sure.  A closer

> look however revealed a lot of simple but informative line

> diagrams and isolated english words like "RGB" and

> "Video" occuring at strategic places throughout the manuall.

>      The first thing I did was try the simplest hookup, namely

> composite video in.   One of the concerns I had was that this

> device might use the same chip and technique of the infamous

> Matco converter.  That thing was no better than a hookup to a

> standard TV.  When I connected this box up and powered up

> the coco, the quality of the output was equal to that of the CM-8!!!

> I am not exaggerating.  I dont know how they did it, but they

> got the same bandwidth through that composite video port as

> the CM-8!!  I guess this device is good enough and the CM-8

> is poor enough so that they endup similar in performance.

> The only significant difference in performance i could find between the

> two was when the color-burst signal is turned off for

> monochrome operation.  This is the code I used:

>

> 10 poke &hE033,16 :poke &hE03C,19 :poke &hE045,19

> 20 width 32 :palette 12,63 :palette 13,0 :cls

> 30 width 80 :palette 0,0 :palette 8,63 :cls1

>

> This code turns the color burst signal off and sets up an 80-column

> screen with white text on a black backround.  The XRGB converter

> would either flicker at a rate of about 3 or 4 times a second

> or would stablize and wash out with artifact colors.  It's like

> it could not decide were to "settle" when generating the display. If you

> execute a sound command the display would flicker and the

> text would be ultra sharp for the duration of the command then

> return to the stable but washed out color artifacted display when the

> command finished.  I tried to attenuate the video output of the coco

> thinking that maybe it was overdriving  the converter, but the result was

> that it would stay in the flickering condition all the time.

>      But if you delete line 10 in the above code and just set the white

> forground and black backround, the converter display had the

> same performance of the CM-8.   There was only the slightest

> artifacting from the converter, almost imperceptable.  You can

> adjust the converters programmable features  to minimize this. With

> any color combination, this converter's composite video performance

> is outstanding to put it mildly.  I guess the conversion process of this

> device depends on ,in some way, the color burst signal for stability.

>

>     All this is good but it does not justify the cost of the XRGB

converter.

> Now it was time to move on to the RGB input.  The manuall called it the

> "game-in" input.   The manual included the pinouts labeled in

> english (thank god ! ).  The connector plugged into the box and

> was terminated with 5 RCA audio style female connectors.  Two

> were actually for left and right stereo audio.  The other three were

> for the three video signals and logically colored according to the signal,

> Red, Green, and Blue.  This is were things get strange.  Remember,

> I'm feeling my way around in the dark with the language barrier.   I

> noticed there wasn't any input for the horizontal or vertical synch

> signals.  It occured to me that maybe they would be combined

> on the green input or something like that.  (I had to go back to

> school about the varies video standards to make sure I wasn't

> missing something).  So I hooked up the signal lines with an opened

> ended cable I keep for the coco for experiments like this and tried

> various configurations with no luck.  I could see the display was

> correct but there was no signal synch occurring.  Just the rolling

> display.  I took another look at the diagram and it showed the synch

> input on a certain pin on the connector but there was no connection

> to it for that pin!  So I decided to disassemble the connector.  This

> turned out to be easy.  A plastic nut that screwed onto the connector

> held it together.  Once removed, it came apart into two pieces revealing

> the solder lugs inside the connector.  I don't know if it was some kind

> of design error or what but the pin that, according to the diaghram,

> was supposed to carry the synch signals wasn't hooked up to

> anything!!

>      To make a long story short, I soldered a wire to that pin and

> brought it out from the connector.  After some scope time and

> a few educated guesses, I determined that the synch signals

> from the coco needed to be hooked up to a nor gate (74LS02) and

> the output of that connected to the newly installed wire.  Upon

> powering up the converter and the coco,  I saw what I had been

> hoping for,  an SVGA image of the coco screen.  It looked every

> bit as good as the screen of an emulator on a modern machine.

> All color combinations and modes where sharp and clear (including

> the color burst off - monochrome mode described above).  I may

> get in contact with the manufactures to see what the deal is

> with the missing input.  It could be that that input is rarely used over

> there and they are unaware of the flaw.

>

>      So this device works extremely well with the coco.  The only

> problems are the cable hack and the high price.  You should

> know that this is an extremely well built and feature packed

> converter.  You can program almost every  aspect of its

> operation.  You can adjust its scanning behavior to match

> it to almost any monitor.  You can control the gain of the

> red, blue and green signals independently of each other. Heck,

> there are even adjustments for stuff I know nothing about. (what

> the heck is "gamma" anyway?).  This converter can sync to

> either 31khz or 47khz.  Could the latter one be for large LCD screens?

> It has the composite video, RGB, S-video and another input I

> don't recognize right off hand.  It even routes audio to your

> PC's speackers.  And It all can be controlled with a remote with

> the size and dimensions of a credit card.

>

>      If any one decides to get this converter,  I can provide details on

> the cable hack.   It was hard to find but easy to do.  I'll do the mod

> for free if not to many people want it, just send me the cable.

>

>      This device is not the ideal solution for the coco.  We need a

> box that simply connects to the coco without all the unnessacary

> bells and whistles at about 1/3 the price.   But this devices does do

> exactly what I think everybody is looking for.

>

>

> Vital statistics:      Manufacturer ----   Pacific Game Technology Ltd.

>                                                        93 Kwai Fuk Road

>                                                        Broadway Centre,

Unit

> B, 17/F

>                                                        Kwai Chung, NT

>                                                        Hong Kong

>

>                              Price + shipping - 209.00

>

>                               email ---------------- www.lik-sang.com

>

> Peace,

>

> Roy R Justus

> rjrtty at aol.com

>

> -- 

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