The MV1200 is an external scandoubler for all Amigas which takes the standard Amiga PALor NTSC output and scandoubles it for use on a PC type VGA/SVGA monitor. It supports full 24bit colour in all non 15Khz modes. High precision TTL circuit used for pixel clock generation. The MV1200 also has an optional FlickerFixer module to promote interlaced screens to non-flickering displays. The MV1200 connects to the RGB Video out on the Amiga and should only be connected when the machine is switched off.
Once you have connected the MV1200 it may be necessary to "finetune" it for best picture quality, although by default it comes fine tuned for A1200s. The MV1200 should be plugged in and the Amiga switched on for at least 5 minutes before attempting this procedure to ensure that the MV1200 has reached operating temperature. Try to have as many vertical lines on the screen as possible, or load a picture which contains many alternate black and white lines. Use a small screwdriver to move the potentiometer labelled Adjust. Please note this is a high performance multi-turn multi-precision potentiometer which can be turned about 20 times from end to end. In the middle of the range there is a distortion of the picture but if you turn it another 3 or 4 times the picture quality will increase. DO NOT forcibly turn it further when you encounter resistance. If you have problems with picture quality still, then close the jumper marked phase. This is normally open.
| LED | When on | When off |
|---|---|---|
| Bypass FF Mode | input H-Freq > 15Khz (24Khz - 31Khz) 15Khz flickerfixed (Flicker Fixer only) |
input H-Freq = 15Khz |
| JUMPER | OPEN | CLOSED |
| Enable | Adjustment Disabled | Adjustment Enabled |
| Phase | Normal Clock Used | Inverted Clock Used |
| FF-Ena | Flickerfixer Mode | Scandoubler Mode |
| 222Mod | 58221 FRAMs Fitted (FF only) | 58222 FRAMs Fitted (FF only) |
Factory Default Setting
Enabled - CLOSED
Phase - OPEN
FF Ena (inside) - OPEN if FF Fitted, otherwise CLOSED
222 Mod (inside) - OPEN if 58221 FRAMs fitted, CLOSED otherwise
XCLKEN (inside) - Reserved, must be OPEN
CCK (inside) - Reserved, must be in left position.
Notes:
In SuperHiRes mode, only every second pixel is displayed
All modes with a Horizontal frequency above 15Khz will be bypassed, but since some of these modes are also outside the VGA range, your monitor may not display them correctly.
Only 15Khz modes will be flickerfixed, other modes will be bypassed
Please ensure that the VGAOnly tool which is part of the monitor drivers, is execute prior to the monitor driver to ensure that Euro72 and Multiscan modes are fully VGA compatible.
Upgrading to a FlickerFixer
To upgrade you need two video-field memories of type OKI 518221Z-30 OR OKI 518222Z-30 in ZIP form.
Open the unit and insert the chips into the ZIP sockets, make sure the writing is facing the 23pin video connector
After fitting, gently bend them towards the 23pin connector to allow the case to close correctly
Open the FF-Ena jumper
Set the 222Mod jumper correctly, according to the FRAM type you used.
The unit draws power from the Amiga itself, so if you're A1200 for example is highly expanded, you may need a better power supply
Thanks to Gunnar Bernhardt