Resolution Switching safe for chassis?

[cr81]

Hi  I just got my groovymame cabinet set up with all the correct resolution for my games.  I noticed when I switch into a game from mame I can hear a click from the chassis when the resolution switches.  Is switching resolutions on the fly harmul to an arcade monitor or chassis. 

[Zebidee]

Hi  I just got my groovymame cabinet set up with all the correct resolution for my games.  I noticed when I switch into a game from mame I can hear a click from the chassis when the resolution switches.  Is switching resolutions on the fly harmul to an arcade monitor or chassis.

The quick answer is no, so long as you are switching to resolutions that are also within the monitor's normal operating range. Which, for most arcade CGA/CRT monitors, centres around 15.7khz +/- around 0.5 khz (horizontal) and between 50-60hz (vertical). With CRT_emulator/Groovymame, you define these operating parameters by the monitor presets (monitor.ini) during setup. Generic 15khz default presets are already provided.

Now for a fuller answer.

The real "danger" zone for CGA (15.7khz) arcade monitors and TVs used with Groovymame is usually the PC startup and boot time, before the desktop loads and the CRTEMU drivers kick in. While booting a PC mostly outputs a default VGA signal at 31khz or higher, that your monitor/TV is not designed to display. For many displays this is a non-issue, it just means no valid picture. Some displays automatically recognise the VGA signal and avoid potential issues by just displaying it twice, thus bringing the effective frequency down to ~15.6khz (you see a doubled, vertical image)

However, for some monitors, even slightly out-of-range frequencies can, over time, cause cumulative damage to the horizontal oscillator and/or phase-locking circuitry. Which monitors, I can't say exactly. The only specific example I've heard of is with Nanao MS8 monitors, where repair technician Joey (JOMAC, Australia) reports that he often gets these monitors for the same kind of repairs, where they have been in regular use with PCs and CRT_emudriver, soft15khz, or similar software.

So if you have a Nanao MS8, or are just worried about this issue for your monitor/TV, leave the monitor OFF until the PC boots to a stable 15.7khz video output. Listen for the desktop startup sounds, wire a 555 timer onto your monitor's power, or just leave monitor off for a couple of minutes.

You can try flashing your video card BIOS with ATOM-15, which can make the boot screens display at 15.7khz, however ATOM-15 does not work with all video cards. Another way is to use a special filtering dongle (filters out video frequencies higher than about 17khz), but these are hard to find. Buttersoft makes them - AFAIK he has not made them for sale, but you could ask.

You can also disable/replace the PC bootup splash screens to minimise the issue.

[cr81]

So the click sound I hear when switching between games is nothing to worry about then?

Thats good news

Thanks

[Jontox]

Clicking sound is not usually a sign of resolution switching only but involves frequencies switching as well usually.

You shall define your setup and the way you launch games to obtain a valid answer on your consideration.