New Astro City Power Supply Queries
Posted: January 30th, 2019, 1:22 am
Hey folks,
I'm about to start a refurb on a project NAC I picked up. It's dead - really dead. So I'm going completely from the start with it, gut the lot.. start again.
So with that in mind, while I work on it.. I'm mindful of what may have stopped things working for a previous owner. It's Japanese spec 100V 50/60Hz in.
Question #1 - Mains Earth!
So I have a lovely step-down and my Astro wired in mains cable with the Japanese 2-pin plug goes into that. All fine.
Inside the cab I notice all the earth points are joined to the earth screw at the back of the mains panel, where in Asia manuals it normally states the operator should connect to a stake in the ground. But.. every Astro I've seen running on a step-down here in the UK, doesn't have that earth connected.
Does nobody run an Astro that's properly earthed while on a step down? (I'm aware that Euro / Hong Kong 240v models have the earth in the 3-pin mains cable)
Question #2 - PSU refurb!
So I'm looking at this pleasant mass of tentacles rolling around lovingly in the base of this cab: At some point the stock Sega 400-5198-01X PSU block failed and a previous owner has ripped out the guts and wired in a switcher. I'll give that a test in isolation and make sure it's not outputting anything crazy, but I see the mains (100v in this case) is fed directly to the harness connectors without any isolation or protection.
Is it right that say the monitor and top light area are run direct from the mains with no ISO transformer at all? Or would the 400-5198-01X normally have had a small 100v / 100v transformer within it?
Question #3 - Sega PSU audio 'amp'
While searching for info on the question above, I found a handy diagram someone had made of how to wire a switcher up to the Sega PSU pcb, so that'll help me check and test things: My final question relates to the audio pot at the front. For sure I know this model of PSU only supported mono from the JAMMA harness, but... would there have been any amplification going on in the 400-5198-01X PSU block, or is that just a phat pot to lower the amplified volume from the PCB amp effectively? Does this mean if I turned the cab volume down to nothing (max resistance) and the PCB amp to max volume, the game PCB sound amp might go 'pop'?
I'll probably do an internal 12v stereo audio amp mod to this cab anyway, but given the original internals have been gutted doesn't provide me with many answers!
Cheers!
I'm about to start a refurb on a project NAC I picked up. It's dead - really dead. So I'm going completely from the start with it, gut the lot.. start again.
So with that in mind, while I work on it.. I'm mindful of what may have stopped things working for a previous owner. It's Japanese spec 100V 50/60Hz in.
Question #1 - Mains Earth!
So I have a lovely step-down and my Astro wired in mains cable with the Japanese 2-pin plug goes into that. All fine.
Inside the cab I notice all the earth points are joined to the earth screw at the back of the mains panel, where in Asia manuals it normally states the operator should connect to a stake in the ground. But.. every Astro I've seen running on a step-down here in the UK, doesn't have that earth connected.
Does nobody run an Astro that's properly earthed while on a step down? (I'm aware that Euro / Hong Kong 240v models have the earth in the 3-pin mains cable)
Question #2 - PSU refurb!
So I'm looking at this pleasant mass of tentacles rolling around lovingly in the base of this cab: At some point the stock Sega 400-5198-01X PSU block failed and a previous owner has ripped out the guts and wired in a switcher. I'll give that a test in isolation and make sure it's not outputting anything crazy, but I see the mains (100v in this case) is fed directly to the harness connectors without any isolation or protection.
Is it right that say the monitor and top light area are run direct from the mains with no ISO transformer at all? Or would the 400-5198-01X normally have had a small 100v / 100v transformer within it?
Question #3 - Sega PSU audio 'amp'
While searching for info on the question above, I found a handy diagram someone had made of how to wire a switcher up to the Sega PSU pcb, so that'll help me check and test things: My final question relates to the audio pot at the front. For sure I know this model of PSU only supported mono from the JAMMA harness, but... would there have been any amplification going on in the 400-5198-01X PSU block, or is that just a phat pot to lower the amplified volume from the PCB amp effectively? Does this mean if I turned the cab volume down to nothing (max resistance) and the PCB amp to max volume, the game PCB sound amp might go 'pop'?
I'll probably do an internal 12v stereo audio amp mod to this cab anyway, but given the original internals have been gutted doesn't provide me with many answers!
Cheers!