Voltage Advice Needed

Post by **Jeff-20** » Thu May 17, 2007 6:23 pm

I have a console (a sega cdx) with a damaged power supply. However, I have another power supply that boots up the unit. The voltage is different. It functions fine, but am I in danger of damaging the console?

Original Supply: wrote:Input: 120V AC 60Hz 23W
Output: 9.5V DC 1.5A

Replacement Supply: wrote:Input: 120V AC 60Hz 15W
Output: 10V DC 0.85A

PaulQ · Post by **PaulQ** » Thu May 17, 2007 9:30 pm

Voltage isn't as important as amperage; most devices can handle a higher than rated voltage (or even lower), but not enough current could cause damage.

Post by **Jeff-20** » Thu May 17, 2007 10:33 pm

Is this too great of a difference?

Mayhem · Post by **Mayhem** » Fri May 18, 2007 5:11 am

There should be a sticker on the unit itself stating what it needs...?

ral-clan · Post by **ral-clan** » Fri May 18, 2007 6:30 am

DigitalQuirk wrote:Voltage isn't as important as amperage; most devices can handle a higher than rated voltage (or even lower), but not enough current could cause damage.

Really? I had heard that it was more dangerous to supply more voltage than needed, whereas you can provide more amps than needed (but not less as you say) and the device will only draw those amps that it needs.

i.e. I direct you to my "sick 1541-II" thread where the faulty power supply was sending 8v on what was supposed to be a 5v line. The extra 3 volts were causing several chips to malfunction and possibly fried one.

I do recall though having used slightly "off ratings" wall wart adaptors in a pinch (like a 9.5v adaptor for a 9v device....or maybe even a 12v adaptor). This was mostly before I knew better. It worked, but perhaps some devices are more tolerant than others?

Doppleganger · Post by **Doppleganger** » Fri May 18, 2007 7:01 am

Usually most IC's will be hurt more by under-voltaging them. Think about overclocking modern CPU's... you normally increase the voltage to get the transistors to switch fastter. In turn, it runs hotter.

But the .5v difference on the power supply probably isn't a big deal, since it most likely has regulators inside the unit, anyway.

The big deal is whether .65A less of available current will damage either the unit (because the voltage will drop as the power supply cannot keep up with the current draw) or the power supply will fizzle out because it's being stressed too much, and possibly blow'd up the unit.

I'd try to find a power supply that more closely matches the original in amperage.

Post by **Jeff-20** » Fri May 18, 2007 10:29 am

What about those "Universal Power Supply"s from Radio Shack? They read:

Power Voltage DC 3, 4.5, 6, 7.5, 9, 12 V (1000 mA)

The focus on Voltage made me think that it was the most important thing. If I find an off brand replacement, I'm likely to have some difference...
...and "1000mA"? Does 1000 Milliamperes out meet my needs? Are these things frying equipment?

carlsson · Post by **carlsson** » Fri May 18, 2007 12:45 pm

It means it would give at most 1000 mA = 1A at any given voltage. Some switchable power supplies have individual amperages for each voltage. If the original power supply was capable of deliver up to 1.5A at 9.5V, you probably would want a replacement supply at 9 or 10V that is rated to supply just as much. A bit of searching the Internet may reveal if the console really draws that much power, but as ral-clan wrote, if the power supply is rated for a higher amperage it shouldn't do any damage as long as the voltage is within the right range.

Doppleganger · Post by **Doppleganger** » Fri May 18, 2007 1:59 pm

http://www.hosfelt.com

Main site...

http://www.hosfelt.com/en-us/dept_8.html

There's the page with 9.5V 1.5A power supplies.

Have at it!

They're only $5.95 each.

Doppleganger · Post by **Doppleganger** » Fri May 18, 2007 2:07 pm

Oh, and they have 9VAC 1A adapters, too... I'm thinking they'd make good PSU's for inside a custom case.

Post by **Jeff-20** » Fri May 18, 2007 2:41 pm

Doppleganger wrote:There's the page with 9.5V 1.5A power supplies. Have at it!

The only problem is that it is a Sega model 2. They have proprietary connections. I tried to splice one of the Genesis 2 cords (with the same proprietary plug) to my original supply. But the problem is not a short along the cord of the original; the problem seems to be within the "box" part of the power supply.

The chance of finding a CDX power supply alone is slim. The best I can hope for is finding a broken console with cables on ebay.

Mayhem · Post by **Mayhem** » Fri May 18, 2007 3:19 pm

Could ask on DP, someone there might have one.

PaulQ · Post by **PaulQ** » Fri May 18, 2007 7:15 pm

Jeff-20 wrote:What about those "Universal Power Supply"s from Radio Shack? They read:
Power Voltage DC 3, 4.5, 6, 7.5, 9, 12 V (1000 mA)
The focus on Voltage made me think that it was the most important thing. If I find an off brand replacement, I'm likely to have some difference...
...and "1000mA"? Does 1000 Milliamperes out meet my needs? Are these things frying equipment?

Look at it this way: Most homes have 100 amps of service. Each circuit in a home usually has a 15 amp breaker; that means that each circuit can provide up to 15 amps of power. Most devices that are plugged in only use a small fraction of that. Thus, the rated amperage of the universal power supply is the maximum that it has been tested at delivering. If your Sega CDX only draws .8 amps, then either power supply would work. However, if it draws 1 amp, the replacement power supply may not be able to provide sufficient current. Note that this would be peak amperage; that is, the maximum amount of power it would require. It is quite possible that, at boot-up, the CDX isn't pulling all the power it requires when it's operating at maximum power.

As for voltage, we all know that household current in North America is 120 volts; however, in actual fact, this fluctuates, sometimes as low as 110 volts, sometimes as high as 130 volts, with no ill effect to devices that are connected since they are usually supplied with more than enough current. Thus, as long as sufficient current is being supplied (amperage), small fluctuations in voltages shouldn't hurt (especially .5 volts).

Boray · Post by **Boray** » Sat May 19, 2007 1:20 pm

With power supplies: It's the voltage that counts. Too high voltage can damage things. The things will run hotter and the life span will be shortened. Too many amperes on the PSU doesn't matter - the PSU won't give more amps than is used by whatever is connected. But with too few amperes, the machine won't work properly. It doesn't get enough power. So in other words: The voltage should be the same or slightly under the original. The ampere should be the same or above the original.

Post by **Jeff-20** » Sat May 19, 2007 5:50 pm

Boray wrote:So in other words: The voltage should be the same or slightly under the original. The ampere should be the same or above the original.

So exactly the opposite of what I have.