Today I was Picking up my Holy Grail of arcademachines at Erik's place (Gravitar) but also had some time to work a bit on some machines.
Erik mentioned he had had some issues with his Galaga and that he changed a "cheap" step-down converter for a "good" one and that the issues were gone after that.
I wondered what the difference could be .......I noticed that these step-downs have a bridge on the backside that makes it possible to select input voltages like 240, 220,200 and another lower voltage I forgot.
They were set up at 240VAC and since we have 230 VAC since decades here I'd expected that to be OK.
However I measured the outgoing voltage and it was only 105Vac.....which is pretty low for a 110 Vac output. When I moved the bridge for 240 to 220 Vac, I got 115Vac on the output.
Erik's Ms.Pac's monitor had a picture that looked like a 30 year old monitor in an arcade looks like....dim, and there was some tiny but clear 50Hz flickering going on in the screen.
I moved the bridge of the step-down to 220Vac and powered the Ms.Pac back up. The picture was now brighter and the flickering was gone !
It seems like the monitor was needing a little more power !
After a bit of adjusting on the focus pot the picture was now very nice for an old monitor like that. It went from "tired" to looking "fresh".
Figured that maybe others might have to check this too....
Something that might be smart to do is to check the +5V on the game PCB after this move because this may have gone up too, depending on the PSU used in that cab.
By the way UNPLUG the step-down converter while moving over the bridge, you can touch the metal pins and you might get a shocking surprise if you do it while it's powered up.....pretty sure they don't get any European safety approvals because of this.
I also opened one up to have a look inside. of course, it's just a transformer basically. Didn't look too bad to be honest. This was a 300W specced transformer I believe....Would't try that but it was sure big enough for a single cab.
