GBS-8220 RGB TO VGA Converter

[MichalQL]

Thanks a lot... I now remember, that the CUB monitor was really piece of a special HW.

In that sense the described RBG -> cables will not get me further then the RGB. Right? And that means either tinkering with the different convertors (I'm bit worried when I read this thread about that), stay with F2/TV (that some SW ignores - ie. unzip) or move to the emulator....

[MichalQL]

Dear Dex,

according to what you write:
-----------------quote
"Monitor" as meant by QL is a special Microvitec monitor with fast beam return.
So, during the time, when the TV beam returns to the beginning of line, the "monitor" beam had already returned and is displaying the leftmost part of QL's framebuffer. I.e., the same graphical data, sent to TV, are "out of screen", as the beam did not arrive to the left screen boundary yet.
So, in fact, the SCART TV is not wrong. The QL's "monitor" mode is wrong.
-----------------end of quote

It is clear that the solution is not at hand and anyone using the GBS-8220 who made it work is a very lucky man! The device is certainly not made to handle this specific QL solution! Just found out on some of the sellers eBay sale following notice:
"please notice : this is only for arcade game use , not for industrial or old computer device use."

This says it all. Hard to say if they know this from the manufacturer or from the complains/returns they get, but certainly there is something behind it.

Thanks & greetings.

[Mr_Navigator]

A video scaler device can solve the problem to a certain extent, I purchased one from J S Technology http://www.js-technology.com/store/, their main guy Dr John Sim was very helpful when I explained the problem with the QL and missing the left hand side columns. They were able to adjust the device (I sent them my QL for the initial set up) as much as possible so that I could just see part of the flashing cursor in monitor mode. Not perfect but as near as dammit.

The device here http://www.js-technology.com/store/prod ... product=12 is their cheapest one, at £59 in the sale.
back view



and I was able to (awhile ago now) get Dr John Sim to write an article for QUANTA about the signals from the QL and how the device basically works.

If you contact them mention the fact you wish to use it for a QL as they can pre-adjust it to suit (as far as they can), although things may have moved on since then. Wouldn't hurt to ask though and before you ask, no I am not affiliated with nor own shares with JS Technology, I just found them really helpful.

[vanpeebles]

Looks like a promising device!

I've since got a 2nd GBS-8220 board but an older revision and that also works fine with a speccy and a bbc. I know other people are using these boards for megadrives and neo geo machines too not just arcade machine use. So it does sound like a puzzle.

[ppe]

Hi,

just a FYI in case anyone runs into a similar problem to mine:

GBS-8220 ver 3.0 would not show a stable picture after I soldered a new cable, with the old cable the picture was ok. With the new cable the picture was jumping up and down on the screen.

Soldering a 300 ohm resistor on the composite sync signal solved the problem for me; the picture is solid again.

Cheers,
Petri

[vanhauen]

I recently purchased a HD9800/GBS8200 version 5.0 board for using an old VGA 17" LCD screen with my Sinclair QL. With a standard RGB SCART cable for the QL (no resistors or other tricks) I used the following wiring to the HD9800 board and got a great and stable picture at first attempt.

Signal HD9800 wire colour SCART pin

RED Red 15
GREEN Green 11
BLUE Blue 7
SCYNC Gray 20
GND Black 17

I am not sure whether my trouble-free experience is due to this being a version 5.0 board but I thought it was worth sharing my result. For completeness, my old LCD monitor is an Eizo FlexScan L565.

[vanpeebles]

Welcome and thanks for sharing Does the v5 have any extras?

[belg4rion67]

great news! I've some doubt to buy new vga converter as the old version not works fine with my ql but if the new v5 works at first attempt... I'buy it asap and check!
thanks so much for your feedback

[Simon_Carr]

This sounds really interesting... If I'm right in my reading, this will allow me to connect my QL to a standard VGA monitor? And be able to use the monitor option on start-up? I may be sold!

[vanpeebles]

Yes