DC into AC power supply - how?

[Skybird]

Does anyone know how to turn a DC-power supply into an AC-unit ? I need to replace the small PS for a very old chess computer of mine, but not only that I need to manually change plugs, i also need to find a workaround for these PSUs being DC for the most (Germany). Someone was claiming on a chess site that the trick is easy to do, but he left before telling me how to do it. We are talking about small plug-devices, 8.5-9V, 1500mA.

[XabbaRus]

Not without a serious piece of kit. Just asked my electrical engineer.

To actually turn the AC to DC adaptor that comes with your chess computer isn't possible.

Though maybe someone will show me I'm wrong.

[Skybird]

Is a device totally non-functional when it needs AC, but gets DC? I simply do not know this kind of stuff. I can attach a wire and isolate it, if needed, and know in principle what A and V means, and that I need to keep an eye on these values when buying a power supply unit. But that is where my knowledge essentially is ending.

[StdDev]

Turning AC (alternating current) into DC (direct current) is fairly easy.. turning DC into AC is a major PITA!
I can assure you that it will be easier (and most likely cheaper in the long run) to find the right king of PS somewhere on the internet.

Do you know exactly what the power requirements are for this device?

As far as an AC device being totally non-functional when supplied with DC .. it depends on the device.. some simple things like some computer speakers will actually work with DC when AC is specified. The best way to test is to try.. as long as you get the Voltage correct and the amps fairly close.. otherwise you will let all the magic smoke out of the electrical components inside the device! :know:

[Skybird]

Hm, since some minutes, I do not need one device, but two. :(First is for a Fidelity Chess Challenger Voice (1979)It demands 8.5V AC (9V still doing well) and 1100 mA (1000 still working well), and alternate current. It is likely that I solved this thing by finding an AC device that matches these values, I just need to cut the wires and attach the old 2-pin-plug to it, isolate it, and hope it works.Second is more tricky, a Fidelity Chess Challenger Sensory Champion (1982). It wants to be feeded with 8.5V (9V) AC and 1500mA. such a device I am seaaching for on the web, ebay, chess computer sites. So far in vain.Will try if the first power unit also works for the Champion, despite the lesser Amperes. I also did not manage to get positive replies from electronic stores if their are adapaters for thes terriubly old connectors. The computers have fixed wires ending in two-pin-connectors, 1mm thick, 4 mm separate, however, the CC Voice has not two poins, but one pin is replaced by one small "square". These plugs I haven'T seen since went to school, and younger salesmen in the electronics sections of warehouses even do not know what I am talking of. Collecting old chess computers is nice - as long as nothing brakes down...

[SUBMAN1]

Hm, since some minutes, I do not need one device, but two. :(First is for a Fidelity Chess Challenger Voice (1979)It demands 8.5V AC (9V still doing well) and 1100 mA (1000 still working well), and alternate current. It is likely that I solved this thing by finding an AC device that matches these values, I just need to cut the wires and attach the old 2-pin-plug to it, isolate it, and hope it works.Second is more tricky, a Fidelity Chess Challenger Sensory Champion (1982). It wants to be feeded with 8.5V (9V) AC and 1500mA. such a device I am seaaching for on the web, ebay, chess computer sites. So far in vain.Will try if the first power unit also works for the Champion, despite the lesser Amperes. I also did not manage to get positive replies from electronic stores if their are adapaters for thes terriubly old connectors. The computers have fixed wires ending in two-pin-connectors, 1mm thick, 4 mm separate, however, the CC Voice has not two poins, but one pin is replaced by one small "square". These plugs I haven'T seen since went to school, and younger salesmen in the electronics sections of warehouses even do not know what I am talking of. Collecting old chess computers is nice - as long as nothing brakes down...
Hmm. I think I just threw away a Fidelity Chess Challenger from 1982 - comes in a golden brown box with yellowish beige and brown squares for the chess board, and the red LED display to call out moves. Had 2 of them - both had issues when they got hot to the point where the computer screwed up and forgot where its own peices were. All of them had this issue.

-S

PS. You best bet is a DC to AC car adapter. Only problem is, those things are bulky.

PPS. Play your game fast because the heat problem will screw you up.

[Skybird]

Don't worry, I know my babies! Heat has been a problem with the fidelity models until the introduction of - hm, let'S say the Sensory8/9-model line. Many pieces fell victim to this problem. I use to position them on 1cm high mini"feet", for that reason, and no textile-covered table. The problem has been at least as great with many Novag- and SciSys-models. Remember , these are the Challengers! Treat them with respect. :) the later arriving Mephistos never had probolems with heat, as to my best knowledge (excluding the high-tuned tournament-machines).

[SUBMAN1]

See - the real issue is - I was such a bad ass chess player, it overheated trying to beat me and failed. That is the real story!:p

[Skybird]

Play with me, then. I make you freeze in no time. :cool:

[SUBMAN1]

Play with me, then. I make you freeze in no time. :cool:

Ouch!

[VipertheSniper]

Ever tried with an old Märklin transformator? I know it's not an ideal solution, but for example my dad made an old turntable which, wasn't intended for current feed from the plug in the wall, but from the amplifier most likely, work with that. What I don't know is if the transformator is regulating the voltage or the amps tho... I also have no idea what how much amps it puts out... the sign on the transformator says 10 W but I guess that's the power drain from the plug in the wall.

[tycho102]

Inverters turn DC into AC. These are extremely common. What is uncommon is "clean" sine-wave AC power. It's cheaper to build step-wave bridge circuits for high-current purposes. Step waves require a bunch of switching regulators, whereas sine-wave requires splitting your signal into three phases (meaning three times the wiring and circuits).

Rectifiers turn AC into DC. These are probably more common than you might imagine. Your computer's PSU is a rectifier. All those little power dongles for your Ipod, radio, Xbox, and laptop are rectifiers. Again the main problem is "clean" power -- in this case it is the "ripple" inside the "DC" voltage.

In terms of the ease of conversion, they are both equally easy. A sine-wave inverter will cost more than a 1mv ripple rectifier, simply because of the extra circuitry and materials involved.



@Skybird--

It's strange that you would be needing 9v AC for a computer (even if it's a chess computer). I would imagine that you actually just need the right rectifier. If the rectifier is hard-wired into the unit and you're trying to run it from your car, well then, yeah -- I could understand the need for an inverter if it was a 220v output like the rest of Europe's AC. In the States, 12vDC-to-120vAC inverters are cheap to find. A 75w inverter (http://www.donrowe.com/inverters/inverters.html) costs $16, and would certainly power that thing.

Heh. You could probably buy a good 220v to 120v "converter" for $20, and use it like that. Highly inefficient, of course, but it would work.

[Skybird]

That's maybe because these computers are not contemporary, but old, I mean: really old: 1979, and 1981! anyhow, thanks guys, but the porblem is solved. I found an electrician in Dusseldorf who as a hobby has specialised in repairing such old chess computers, he also can build such power suppliers, and with the right connectors already attached. 60 euros for both, inclusive shipping, that is a fair price, considering that the original PSUs twenty years ago usually were sold for 100 D-Mark (50 euros) per piece.Seeing a chess computer without PSU is like seeing a baby without it's milk bottle :( It makes my heart cry...

[SUBMAN1]

Inverters turn DC into AC. These are extremely common. What is uncommon is "clean" sine-wave AC power. It's cheaper to build step-wave bridge circuits for high-current purposes. Step waves require a bunch of switching regulators, whereas sine-wave requires splitting your signal into three phases (meaning three times the wiring and circuits).

Rectifiers turn AC into DC. These are probably more common than you might imagine. Your computer's PSU is a rectifier. All those little power dongles for your Ipod, radio, Xbox, and laptop are rectifiers. Again the main problem is "clean" power -- in this case it is the "ripple" inside the "DC" voltage.

In terms of the ease of conversion, they are both equally easy. A sine-wave inverter will cost more than a 1mv ripple rectifier, simply because of the extra circuitry and materials involved.



@Skybird--

It's strange that you would be needing 9v AC for a computer (even if it's a chess computer). I would imagine that you actually just need the right rectifier. If the rectifier is hard-wired into the unit and you're trying to run it from your car, well then, yeah -- I could understand the need for an inverter if it was a 220v output like the rest of Europe's AC. In the States, 12vDC-to-120vAC inverters are cheap to find. A 75w inverter (http://www.donrowe.com/inverters/inverters.html) costs $16, and would certainly power that thing.

Heh. You could probably buy a good 220v to 120v "converter" for $20, and use it like that. Highly inefficient, of course, but it would work.

He is not smoking something - I think those old Fidelity jobs were AC. Definitely not a common thing now, but was more common back in 1982.

-S

[Wim Libaers]

But if they need AC (sine wave I assume) of the same frequency as mains power (I did not see frequency specified), you could just use a transformer with matching specifications.

[SUBMAN1]

That's maybe because these computers are not contemporary, but old, I mean: really old: 1979, and 1981! anyhow, thanks guys, but the porblem is solved. I found an electrician in Dusseldorf who as a hobby has specialised in repairing such old chess computers, he also can build such power suppliers, and with the right connectors already attached. 60 euros for both, inclusive shipping, that is a fair price, considering that the original PSUs twenty years ago usually were sold for 100 D-Mark (50 euros) per piece.Seeing a chess computer without PSU is like seeing a baby without it's milk bottle :( It makes my heart cry...

You will get a better PSU too - the old ones broke and quit working after some time.