GBS-8220 RGB TO VGA Converter

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flyer.gio
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Re: GBS-8220 RGB TO VGA Converter

Postby flyer.gio » Thu Nov 14, 2013 5:27 pm

vanhauen wrote:I recently purchased a HD9800/GBS8200 version 5.0 board



Hi vanhauen,

could you please post a link of the v.5.0 seller's website?

Thanks a lot
Gianni


vanhauen
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Re: GBS-8220 RGB TO VGA Converter

Postby vanhauen » Sun Nov 17, 2013 12:00 pm

No problem. I bought from eBay and the seller has an impressive range of products within their store. Here is the link: http://www.ebay.co.uk/itm/170855156687


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schombi
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Re: GBS-8220 RGB TO VGA Converter

Postby schombi » Wed Nov 20, 2013 7:10 pm

I bought the Video Scalar unit Mr_Navigator mentioned on the previous page. I got in touch with John Sim from JS-Technology and he agreed to do the "QL-mod" prior to shipment. However, when I connect my QL with the RGB-SCART (from Retrocomputershack) cable to the unit and a(ny) VGA monitor, I get an on-off-on-off picture, so the screen is shown for 0.5s, then disappears, comes back, disappears and so on. Did I miss something?

Edit: To add more confusion, there was a note on my sales receipt saying" Will still require voltage on pin 16 for RGB operation". Not really sure what this should tell me? Would it cause the behaviour I´m seeing?

Edit2: John Sim wrote back to me; he´s really helpful und reactive:
----------------------------------------------------------------------------------------------------------------------
if you're getting a colour picture, even for a moment, it means that the lead is supplying the voltage on pin 16. It's a signal which tells the display that RGB is available and I just warn people as sometimes it's not connected.

Which monitor have you tried the converter with? Most good quality monitors should work with this converter as they should adapt to the video output. It's a basic video scalar that double the lines. With NTSC (US TV) this fits perfectly with a VGA type signal. For PAL, the UK system, it sits between two resolutions. If the screen is able to adapt it will show it. If it's a type of screen which only works on fixed points it will do as you're seeing.

In the office we've got a variety of different monitors. All work with the exception of the Dell one. Unfortunately the only way to tell really is to try
----------------------------------------------------------------------------------------------------------------------
So it´s down to my monitors. I will try some more monitors. Which model numbers are known to be working with the Video Scalar?


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schombi
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Re: GBS-8220 RGB TO VGA Converter

Postby schombi » Fri Nov 22, 2013 7:20 am

Giving an update to my own question:

John was right; the monitor was to blame. I tried an unknown Fujitsu-Siemens 17" TFT, a HP Compaq LA2205wg and a Samsung SyncMaster B2430, but all with bad results (on-off picture). Finally an EIZO FlexScan M1900 gave a steady pciture and with the auto-adjust I can now see the cursor in the QL monitor mode. So that´s good news. Just a bit confused about the picture being a bit jumpy and also the black parts of the screen seem to show some fine lines/stripes of different lenghts, which looks looks like heavy rain. :?:


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Re: GBS-8220 RGB TO VGA Converter

Postby QLObi » Fri Nov 22, 2013 10:01 am

Hi Guys,
just to add another experience with the VGA problem to the thread.
Yesterday i got my GBS-8200 Ver4.0 and i was able to connect a standard VGA monitor to the QL. The pins were the classic ones RGB,GND and Csync.
The solution works perfect with a German QL issue 7, but no chance with my English Issue 5 one. But i am already aware that this machine has unstable signals, even on the digital site. I am getting only noisy pictures on all outputs from it (time to look for the error).
The VGA converter works with all modes. No chance to test with a Q60.

QLObi
PB214616.JPG



Latest news: On my issue 5 i added the resistor (1K Ohm), described earlier, in seriell to the C-Sync line and got a stable picture. On the oszillocope i saw a serious defoming of the signal wihout the resistor. I put also 100 Ohn in seriell to the RGB line to protect the ZX8301.
The noisy internal signals of the Issue 5 just causes a very light noise on black areas. But who cares if you now can use a cheap standard mointor. On the picture the monitor is in 1024/768 mode, so the QL picture is strechted a bit in vertical, but that can be adjusted on your demand.
I paid just 30 Euro (inc P&P) in ebay for the adapter.


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Re: GBS-8220 RGB TO VGA Converter

Postby RWAP » Mon Oct 13, 2014 10:33 pm

Dilwyn,

Can you add some details about these boxes to the back to the QL page on the QL homepage - I am asked all the time and it is hard to keep finding this forum topic :D


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Re: GBS-8220 RGB TO VGA Converter

Postby QLObi » Thu Oct 30, 2014 12:30 pm

Latest news on GBS-8220.
Beside the resistor (1k to 2k) in seriell to Csync it's also important to use shielded wires for RGB and
normal wires for the sync signal. Otherwise you might encounter a light disturbance on showing characters on the screen.
The sync signal might work also with a shielded wires, but in generell there is a unbalance between impedance of cable and input/outout of devices.
Resistors in seriell to the videosignals (50 to 100 Ohm) can be omitted, just protection. If you install them, put them as close as possible to the QL (in the plug).
Version od GBS needs to be V4 and higher.
In this configuration my Black Box with GBS-8220 was shown on the 30isShow in Edinburgh.

Detlef


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Re: GBS-8220 RGB TO VGA Converter

Postby Derek_Stewart » Thu Oct 30, 2014 2:15 pm

Hi Detlef,

I thought the display on your QL at Edinburgh was excellent.

Can you post a diagram of the connections from QL to GBS8220.

So that everyone can use this interface correctly.


Regards,

Derek
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Re: GBS-8220 RGB TO VGA Converter

Postby QLObi » Fri Oct 31, 2014 9:37 am

Hi Derek,
i draw my configuration on a paint picture. Hopefully not to technical.
The other picture shows the real converter as used on the Edinburgh meeting.

Detlef

ps: As already mentioned, best place for protection resistors is as close as possible to the QL. But easiest is at the pinheaders of the GBS8220. There is next to no impact to the picture.
It's also a good and safe practise to isolate with shrinking tub. For better demonstation of the resistor not done here.
Attachments
Cable.png
Drawing of connections
PC094764.JPG
GBs 8220 wired to DIN connector


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vanpeebles
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Re: GBS-8220 RGB TO VGA Converter

Postby vanpeebles » Fri Oct 31, 2014 9:41 am

Interesting how you used the pole terminals. I used the P11 connection on mine. The picture on yours was very crisp at the show :D



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