My scanner power supply is broken!!!

[allthatwhichis]

Long story short, I was messin around, adding a power switch to my projector and grounded the 120V a time or two, or three... This caused my scanners not to work. I have found a burn resistor on my +/-24V PSU. From a color code decoder web site I am fairly certain it is a 6.8 OHM 1/4W 5%.

I found 100 of them on eBay for $1.00... but I'd like to find one local.. I have been looking at dead electronics in my house and can't seem to find one. Where is a good place to get these? Radio Shack didn't have them... Is it something a brilliant geinus like myself can change? Will Skycrafters have them and should I try and get a whole new power supply there while picking a few dozen of these up? Assuming I can slip away from work tomorrow.

[FourDee]

I don't mean to be pessimistic, but there may be more stuff broken than just one resistor. ( have you checked the fuse? carefully examined the whole board? )

If you manage to find all the faulty parts and replace them, you should be ok

[survey]

Hi allthatwichis, a 6,8 ohm resistor with 1/4w looks like some kind of surge protection. You can found them on many electronic circuits, have you a computer power supply around?
It could be also a sensing resistor that fails when the circuit it is feeding comsumes a lot more than usual.
But please note as FourDee says maybe you have more components broken, open circuit or even short.

[dave]

Aaron,

Ill get a spare PSU to Adam with the scanners I will be sending in the next couple of weeks Easy

[allthatwhichis]

Thanks guys.

I have done a "fairly" complete inspection of the board. The only visual fault I can find is the "blackened" resistor. I will try to swap this out and see if that fixes it, if not, I will just look for another power supply. I have found the same supply online for about $100. None on eBay though...

I have also checked all that dead electrical devices I can find and cannot find that specific resistor. I have only opened one computer PSU, but I have 3 or 4 sitting around. I will open them up to check when I get off work tonight.

[allthatwhichis]

Aaron,

Ill get a spare PSU to Adam with the scanners I will be sending in the next couple of weeks Easy

You're the man dave! I am not sure a new scanpro PSU will solve my issue. One of the scanpro's died before FLEM 2. We swapped it out with a DT40 but had to use the power supply dreambeamz gave me for the G120s. I still have the scanpro power supply, but I do not think it will power the DT40. My memory is foggy, but for somereason it wouldn't work with the DT40... That is why we... I say
"we", , DZ wired it... That is why we used the +/- 24 volt PSU for the G120s. I know there is a special name for the PSU, switching... differential... dual output? but you know me. I forget. I plan to go by Skycrafts today to see if they have a PSU and some of the resistors.

[DZ]

SkyCraft has a nice selection of supplies, but they have an amazing supply of resistors. Most of the smaller ones are sorted in little bags up near the registers. I strongly suspect that there will be more damage than just the resistor. I'd just get another supply, or build one if SC doesn't have what your looking for. Linear supplies are so very simple to build and SC will have every part you need for one. Damn, it was so nice when I lived just a few blocks from them!

[buffo]

Dave;

Now that's customer service!

Aaron;

The DT-40's run off a 24 volt power supply. I think the Scan-pro's run off an 18 volt power supply.?. Dave can confirm this. Not sure what the DT-40 would do if you ran it at the lower voltage; probably would be fine though. Still, this means that you were running the one Scan-pro galvo you had at *higher* than it's normal voltage, yes?

DZ;

You worked on his projector at FLEM Mark II, right? Do you remember if there was a voltage difference between the two scanner power supplies? Do you think there would be a problem running the DT-40 amp off the Scan-Pro power supply?

Adam