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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: djkoelkast on July 31, 2013, 12:46:58 PM

Title: Amiga to GB-8200/8220 through RGBHV?
Post by: djkoelkast on July 31, 2013, 12:46:58 PM: I had to have a cable lying around that I never used. It was DB23 to DB9. Took it apart and hooked it onto the GB-8200 converter with R G B, Composite Sync and GND.
Problem was: white speckles all over the place when there was a black screen, losing sync every now and then, resulting in shaking image.
So I tried something else: hooking up the Amiga through the RGBHV (VGA port) port of th GB-8200. Redid the cable R / G / B / HSync / VSync / GND, but it doesn't work, the Amiga doesn't even boot, so clearly there's something wrong.
Any hints on this?

I've used pins 3, 4, 5, 11, 12 and GND 16, 17 & 18
On the VGA side I've used pins 1, 2, 3, 13 & 14 + GND.
Title: Re: Amiga to GB-8200/8220 through RGBHV?
Post by: amiman99 on July 31, 2013, 04:17:18 PM: It doesn't work, the VGA input is only 31khz. See the spec page.

Input signal
CGA/EGA
14.5kHz - 16.5kHz
23.5kHz - 25.5kHz
30.5kHz - 32.5kHz
Auto scan
P3 or P11 or P10
RGBHV
30.5kHz - 32.5kHz
Auto scan
P10 or P11
VGA
30.5kHz - 32.5kHz
Auto scan
P10 or P11
Ypbpr
480p,576p,720p,1080p
Auto scan
P2
Ycbcr
480i,576i,720i,1080i
Auto scan
P2

edit: copy/paste didn't work to well.
Title: Re: Amiga to GB-8200/8220 through RGBHV?
Post by: djkoelkast on July 31, 2013, 04:34:25 PM: Too bad, mine came without any instructions or spec sheet, so I didn't know.
Isn't there a way to use HSync & VSync for a better sync on this thing through the RGBS port?
Or should I just put HSync in stead of Composite Sync to the connector? The connector that was supplied with the board had some pins not connected, GND(2) and VSync have no cable attached to them. Others do. RGBS has the HSync, which was connected to the Composite Sync of the Amiga (according to a pinout I found online).
So would connecting HSync in stead be a better option?
Title: Re: Amiga to GB-8200/8220 through RGBHV?
Post by: amiman99 on July 31, 2013, 04:59:34 PM: I used these settings and pin outs below with good results:

HPOS 56
VPOS 16
HSIZE 48
VSIZE 55
CLAMP ST 97
CLAMP SD 00

or

HPOS 50
VPOS 14
HSIZE 50
VSIZE 56
CLAMP ST 97
CLAMP SD 00

These settings work in
PAL and NTSC.
Good luck.

The converter is labeled pretty good
All pins are on Amiga side:

PIN 3 RED
PIN 4 GREEN
PIN 5 BLUE
PIN 10 CSYNC
PIN 19 GND

Edit: one more thing, if things don't work, press the "Auto" button, to find the signal.
Title: Re: Amiga to GB-8200/8220 through RGBHV?
Post by: djkoelkast on July 31, 2013, 05:06:53 PM: It did work, but I had horrible sync and even worse white specks in the image when black. I'll try this tonight, thanks!