Software Support > Automated Projects
Setting up Mame / Mala with rotating CRT (Mrotate4)
Ropi Jo:
A little update on progress......
And another weekend has flown by. Managed to grab 2 hours to get the auto degaus almost to the point of 'ready to test'.
I've got 2 x 2 pin 9ohm ptc. I'm hitting one of them with a 2 second supply at the end of each rotate. Next rotate hits the other one. I'm hoping 2 seconds is enough for the degaus without getting the ptc so hot it takes so long to cool that it won't be ready when needed again. Alternating them will help, as will the cooling fans that run directly onto both ptc. There's also a manual push button degaus through the original ptc that will also have a 2 second timer (not yet fitted).
The original PTC (3 pin) (not necassarily the correct ptc although it did work) was 23ohm, with the coils at 30ohm, so initial resistance of 53ohm. With UK mains voltage that gives me an initial current of approx 4.5A
I put the 2 x 9ohm ptc in series with a 15ohm wirewound, so 24ohm plus the 30ohm coils.
Testing the current through a 30ohm wirewound , using an analogue clamp meter, the action appears to be very similar through all 3 circuits.
I hope this will work and then I can get onto the serial board and Mrotate.
DaOld Man:
--- Quote from: Ropi Jo on August 16, 2020, 06:39:35 pm ---A little update on progress......
And another weekend has flown by. Managed to grab 2 hours to get the auto degaus almost to the point of 'ready to test'.
I've got 2 x 2 pin 9ohm ptc. I'm hitting one of them with a 2 second supply at the end of each rotate. Next rotate hits the other one. I'm hoping 2 seconds is enough for the degaus without getting the ptc so hot it takes so long to cool that it won't be ready when needed again. Alternating them will help, as will the cooling fans that run directly onto both ptc. There's also a manual push button degaus through the original ptc that will also have a 2 second timer (not yet fitted).
The original PTC (3 pin) (not necassarily the correct ptc although it did work) was 23ohm, with the coils at 30ohm, so initial resistance of 53ohm. With UK mains voltage that gives me an initial current of approx 4.5A
I put the 2 x 9ohm ptc in series with a 15ohm wirewound, so 24ohm plus the 30ohm coils.
Testing the current through a 30ohm wirewound , using an analogue clamp meter, the action appears to be very similar through all 3 circuits.
I hope this will work and then I can get onto the serial board and Mrotate.
--- End quote ---
Sounds good. Just remember the serial port is good for only around 10 milliamps (not sure about that, but I know its pretty low). Also, dont forget that the pin goes to around negative 12 volts to ground when "Off", so you may need blocking diodes to keep the negative voltage from your drive circuit. Wouldn't want to fry anything. Its around positive 5 vdc to ground when "On".
Ropi Jo:
--- Quote from: DaOld Man on August 16, 2020, 07:11:20 pm ---Sounds good. Just remember the serial port is good for only around 10 milliamps (not sure about that, but I know its pretty low). Also, dont forget that the pin goes to around negative 12 volts to ground when "Off", so you may need blocking diodes to keep the negative voltage from your drive circuit. Wouldn't want to fry anything. Its around positive 5 vdc to ground when "On".
--- End quote ---
The good news is that the auto degaus works perfectly. Much better than I expected (or even hoped) with my 9ohm ptcs salvaged from an old chassis (which I think was my old 36" widescreen Matchline).
Turned the timers down to just 1 second so they are ready to degaus again within 30 seconds.
Next is mRotate with the serial board I grabbed a while back. I'll have to have a few re-reads of all the info the old man has put on here and wind the key on the old brain a little more.
DaOld Man:
Good show!
Ropi Jo:
Hi Old Man.
Started with mrotate today, and as expected my IT skills (or lack of them) is letting me down badly.
I installed the serial card no problem, and downloaded mrotate4.
Then I'm lost.
I put it on the desk top and double clicked the exe.
It told me there was no ini file and I need to go to setup.
I went to set up and looked at the test panel.
When I closed the test panel it told me mscomm32.ocx was missing or screwed.
I d/l that and stuck it in the same folder as mrotate.exe.
Managed to create an ini (not sure I know how though), but still no idea what I am doing.
Can you give me a simple step by step please? I am totally lost.
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