bfollowell Posted December 23, 2020 Share Posted December 23, 2020 DP & SP mean double-pole and single-pole. These refer to either one or two sets of contacts so that the switch will operate either one or two completely different circuits. DT & ST mean double-throw and single-throw. Single-throw switches are your standard on-off switch. Double-throw switches are of the on-off-on variety, with two different on positions. So, your standard light switch in your home would be a SPST switch. I would think a SPST switch would be what you would need for your Mega STE. That's as much as I'm willing to recommend though, as I know nothing about Megas or their cases. I don't want to recommend something that, because of the size, won't work with your case, or will require heavy case modification. Just look for SPST 120VAC switches of whatever type you look for. I'd look for something in the 2.5 to 3A current range. Quote Link to comment Share on other sites More sharing options...
guus.assmann Posted December 24, 2020 Share Posted December 24, 2020 (edited) @pixelmischief Just now I had a look at the switch. The type (building form) will do just fine. It sort of looks like the one used in the original power suppply. But you should take one that's rated for 125V-AC. This rating is mainly for the fact that the connections should not be too close. There's some rules for that. In Netherlands (230V-50Hz) the minimum distance has to be 5mm (about 0,2") This is called "creep distance" Peronally, I'd choose a double-pole switch and make sure to use a 3 lead-connection. That is with protective earth connection. BR/ Guus Edited December 24, 2020 by guus.assmann Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted December 25, 2020 Author Share Posted December 25, 2020 On 12/24/2020 at 11:17 AM, guus.assmann said: Peronally, I'd choose a double-pole switch and make sure to use a 3 lead-connection. Thanks! Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted December 28, 2020 Author Share Posted December 28, 2020 @bfollowell Can you give me a few sentences on how I should split the 6 outputs on the power supply to the larger number of input pins on the Mega STe system board? Quote Link to comment Share on other sites More sharing options...
guus.assmann Posted December 28, 2020 Share Posted December 28, 2020 (edited) Hello, Some lines? I hope the attachment will do much better. As a Chines proverb says: One picture is better than 1000 words. NB: TT and STE-pwer supplies are identical. BR/ Guus TT_Power_Wires.PDF Edited December 28, 2020 by guus.assmann NB: added Quote Link to comment Share on other sites More sharing options...
bfollowell Posted December 28, 2020 Share Posted December 28, 2020 (edited) 6 hours ago, pixelmischief said: @bfollowell Can you give me a few sentences on how I should split the 6 outputs on the power supply to the larger number of input pins on the Mega STe system board? @pixelmischief, sorry, I can't, at least at the moment. I'm at work for a 10-hour day today and today's my anniversary and the wife and I are going out to eat tonight. I can provide pictures and show you what I did for my STe, but I'm not at all familiar with the internals or the power connector pinout of a Mega STe and I don't want to steer you wrong. I'll look at the Mean Well PSU pinout to remind myself and then I'll see if I can find a Mega STe pinout online and will advise tomorrow, assuming no one pipes in before then. Edited December 28, 2020 by bfollowell Quote Link to comment Share on other sites More sharing options...
Umberto Posted December 28, 2020 Share Posted December 28, 2020 https://www.exxoshost.co.uk/atari/store2/#0032 Quote Link to comment Share on other sites More sharing options...
bfollowell Posted December 28, 2020 Share Posted December 28, 2020 You can download an Atari Mega STe PSU technical document. On the bottom left of page four is a wiring legend for all three connectors coming from the Atari Mega STe PSU. You will need to match those up with the right wires from the Mean Well PSU. You can also download a Mean Well PSU datasheet. Obviously, you will have to attach multiple wires from the various Atari connectors to the PSU leads as there are more than you have available from your PSU. According to the technical documentation, the Atari Mega STe PSU was a 65W PSU, while this one is only a 49W PSU. I'm not convinced it will provide enough power for a Mega STe, but I guess there's a chance that the original PSU was overkill for what was needed and that this one will be fine. @Umberto says he uses it with no issues and I have no reason to doubt him. I'm just going off the rating for the original PSU. Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted December 28, 2020 Share Posted December 28, 2020 If I recall my theory from many moons ago, PSU's are usually rated @75% to 80% of the normal load so for the 65W PSU it's normally running somewhere around 50W. So the 49W PSU might be running at it's max power all the time (which maybe ok for modern PSU's with adequate cooling), just thought I would say Quote Link to comment Share on other sites More sharing options...
Umberto Posted December 28, 2020 Share Posted December 28, 2020 I have it installed in a Mega ST. If its a MSTE with a HDD solution like CosmosEX or a ultra satan(no mechanical drive) it will work just fine. -5v is still needed but can be added easily Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted December 29, 2020 Author Share Posted December 29, 2020 @bfollowell Actually, my question is much more embarassingly simple. In cases where I need to connect multiple inputs on the system board to a single output on the power supply, can I just split them out? Should I chain them to the same wire? Do I need to add some component that protects against reverse flow? Yeah, I'm that green. Quote Link to comment Share on other sites More sharing options...
bfollowell Posted December 30, 2020 Share Posted December 30, 2020 4 hours ago, pixelmischief said: @bfollowell Actually, my question is much more embarassingly simple. In cases where I need to connect multiple inputs on the system board to a single output on the power supply, can I just split them out? Should I chain them to the same wire? Do I need to add some component that protects against reverse flow? Yeah, I'm that green. If the PSU has a +5VDV output on one wire, and you need that for three different wires going into your computer, just wire them all to the same +5VDC wire coming out of your PSU. The same goes for +12VDC. If you need -5 or -12VDC, just wire them in reverse to reverse the polarity. Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted December 30, 2020 Author Share Posted December 30, 2020 8 hours ago, bfollowell said: If you need -5 or -12VDC, just wire them in reverse to reverse the polarity. What do you mean, "wire them in reverse"? Quote Link to comment Share on other sites More sharing options...
ParanoidLittleMan Posted December 30, 2020 Share Posted December 30, 2020 You can not get - voltages by 'wire them in reverse' . GND is common and not separated for diverse voltages. 1 Quote Link to comment Share on other sites More sharing options...
bfollowell Posted December 30, 2020 Share Posted December 30, 2020 2 hours ago, ParanoidLittleMan said: You can not get - voltages by 'wire them in reverse' . GND is common and not separated for diverse voltages. You're exactly right. I was coming back to correct myself when, luckily, I saw you'd already commented. I was definitely having a "I've been at work far too long" moment. The more I think about it, according to the Mega STe PSU document that I found, the Mega STe requires +5VDC and -5VDC, as well as +12VDC and -12VDC. The Mean Well RPD-60A PSU that I linked to only provides +5VDC and +12VDC; no negative voltages at all. I linked to the wrong PSU. Also, the one that @Umberto linked to doesn't provide all the required voltages either. Regardless of which model of RPT-60 you pick, from what I can see, they each only provide 3 voltage rails and, according to the Mega STe PSU document I found, the Mega STe needs 4 separate power rails. I know Uberto said he uses it with his machine, but I really don't see how. Umberto, can you elaborate how you use the Mean Well RPT-60B for your Mega without a -5VDC rail? What am I missing? Thanks. Quote Link to comment Share on other sites More sharing options...
bfollowell Posted December 31, 2020 Share Posted December 31, 2020 Until Umberto clears things up and lets us know how he's running without the -5VDC provided by the original Atari Mega STe PSU, I'm forced to recommend one of these two models, both of which provide all four required DC voltage rails with the correct amount of current. The Mean Well RQ-85B and the Mean Well RQ-125B. They're $37 and $41 respectively. The RQ-125B provides a little more current for the extra $4 and, if it were me, I'd probably go with that one just to cover my bases for any future upgrades and add-ons I might be considering. Not being all that familiar with the Mega STe, I have no idea how these models compare to the original in relation to physical size or whether or not they'll fit. I was just looking at strictly meeting the power requirements. Quote Link to comment Share on other sites More sharing options...
Umberto Posted December 31, 2020 Share Posted December 31, 2020 https://www.amazon.com/Positive-Negative-Voltage-Boost-Buck-Converter/dp/B07SJ4ZXYQ/ref=asc_df_B07SJ4ZXYQ/?tag=hyprod-20&linkCode=df0&hvadid=475741834053&hvpos=&hvnetw=g&hvrand=2655686133481039203&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033519&hvtargid=pla-1032401992282&psc=1 Buck converter will give your -5v rail from the 12v rail. Like I said in post 35, I have one installed in a Mage ST not a MSTE. Mage ST only has a 5v and 12v rails. https://www.digikey.com/en/products/detail/mean-well-usa-inc/RQ-85B/7706154?s=N4IgTCBcDaIEoEUC0AOArAIRAXQL5A Your right this would be a better choice. The other one you listed is to long to fit in a Mega STE Quote Link to comment Share on other sites More sharing options...
bfollowell Posted December 31, 2020 Share Posted December 31, 2020 (edited) 19 minutes ago, Umberto said: Like I said in post 35, I have one installed in a Mage ST not a MSTE. Mage ST only has a 5v and 12v rails. Ahhh, now I see where I was getting mixed up. I mistakenly thought you said you had that one in a MSTE. Thanks for clarifying that for me. That little buck converter is a pretty neat little device too, though I think I'd prefer to stick with one PSU. Still, it might come in handy for some projects. Edited December 31, 2020 by bfollowell Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted January 16, 2021 Author Share Posted January 16, 2021 I'm getting around to hooking this power supply up and am confused by a difference between the actual power connector on the system board and the schematic. In particular, the schematic has +5v on a pin that is absent on the board (marked by a red arrow). What am I missing? Quote Link to comment Share on other sites More sharing options...
guus.assmann Posted January 16, 2021 Share Posted January 16, 2021 Hello pixelmischief, You're missing the pin, obviously. :-) Now seriously, it seems likely that the pin is missing for a reason. It may have been a reversing safeguard. To be sure, you'd need to verify with the original power supply. If it has no wire on that position it's clear. Does it look like the pin is broken of? Can't see that on the picture. If there's a piece of pin left, check for continuity between the pin-part and the last 3 pins of the connector. I'm writing this, without having a look in a Mega STE. I do have one, but it's quite some work to get it and open it up. Maybe Frank Lucas has one available that's also opened up and still complete. BR/ Guus Assmann Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted January 16, 2021 Author Share Posted January 16, 2021 The pin is missing on mine and it doesn't look like a break. Also, I have seen several pictures online that have it missing. I'm not connecting live power to anything until I am sure. Quote Link to comment Share on other sites More sharing options...
bfollowell Posted January 16, 2021 Share Posted January 16, 2021 I know you said that it doesn't look like the pin is broken off. Is there any metal there at all, where you can cvheck for continuity between pins 2 and 10, 11 & 12 like @guus.assmann suggested? If not, maybe you can check from the back of the motherboard to those three points. Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted January 16, 2021 Author Share Posted January 16, 2021 No metals, and no connection. Below is a picture from the bottom of the board and it doesn't appear to even have a trace to the pin. Quote Link to comment Share on other sites More sharing options...
pixelmischief Posted January 16, 2021 Author Share Posted January 16, 2021 Also, any idea what I should do with the PWRGOOD signal? Quote Link to comment Share on other sites More sharing options...
snarkdluG Posted January 16, 2021 Share Posted January 16, 2021 1 hour ago, pixelmischief said: Also, any idea what I should do with the PWRGOOD signal? https://en.wikipedia.org/wiki/Power_good_signal Quote Link to comment Share on other sites More sharing options...
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