What blew out?

Can I ask you how you got the board looking so clean? I took apart a dozen or more DC-DC converters and the epoxy is everywhere. I have never seen one NOT potted. Plus the fact most of these puppies are under fifty bucks list price and closer to 30 or 40 bucks. For the time it takes to repair a converter maybe just swap it out. How did you know it went out when you hit a bump? I didn't know mine went out till a cop stopped me for no lights. Then I looked and didn't see green arrows on blinkers or yellow blinkers on scooter. Most things are cheaper on eBay but converters are higher than list for some strange reason. It looks like a slow failure and not a catastrophic major failure? One of my latest failures was major black inside including board fried.

Well I had the same failure. same resistor and cap. I replaced the resistor (best guess from looking at it once removed, not as burnt on the bottom) and the cap which was originally a 25v but could only find a 16v and it did not fix it.
I had shorted the positive lead of my fifth battery to the frame while the ignition and lights were on.
For $26 I ordered one from extreme.

My circuit board is a little different from yours. The resistor that fried was 1/2 watt the rest are 1/4 watt as in your pic, and there is room for 6 resistors in each row but 1 in each row is not installed. the values of the ones installed are the same as yours.

The lead that I shorted to the frame had a 10A fuse and neither the converter or lead fuse blew.

If I get bored I may try to troubleshoot it further, but for $26 I wasn't really motivated too.

If you have an old switching power supply laying around you can use that. laptop and lcd tv power supplies work. There is a post on here about doing this. I found an old power supply from my kids toys that put out 12v. When I hooked it up it ran on my 72v dc battery pack even though it said 100-250v on the power supply. I always thought it needed ac voltage but it doesn't. Worth a try and if you do this then upgrading to 72v or 84v won't be a problem for your dc converter.

If you have an old switching power supply laying around you can use that. laptop and lcd tv power supplies work. There is a post on here about doing this. I found an old power supply from my kids toys that put out 12v. When I hooked it up it ran on my 72v dc battery pack even though it said 100-250v on the power supply. I always thought it needed ac voltage but it doesn't. Worth a try and if you do this then upgrading to 72v or 84v won't be a problem for your dc converter.

How did you wire it? Did you hooked the input ground to the output ground and were able to get the 12v output. That is interesting. I wouldn't want an open frame supply but a sealed one that could put out 10 amps would work great. I will have to look into that if I have another failure. Was it enough power for your lights and signals? Have you tested it for any length of time as a replacement?
Thanks.

You will discover that about 99% of the time, a failure such as yours is due to multiple problems! Resistors do NOT just "self destruct" as a rule, they fail because somthing ELSE has failed, often a transistor or diode. Hitting the bump probably caused wiring to touch where it should not, blowing a transistor, which then caused an excessively high output voltage, which damaged the resistor and capacitor, so simply replacing the capacitor and resistor is not likely to repair your problem!-Bob

If you have an old switching power supply laying around you can use that. laptop and lcd tv power supplies work. There is a post on here about doing this. I found an old power supply from my kids toys that put out 12v. When I hooked it up it ran on my 72v dc battery pack even though it said 100-250v on the power supply. I always thought it needed ac voltage but it doesn't. Worth a try and if you do this then upgrading to 72v or 84v won't be a problem for your dc converter.

How did you wire it? Did you hooked the input ground to the output ground and were able to get the 12v output. That is interesting. I wouldn't want an open frame supply but a sealed one that could put out 10 amps would work great. I will have to look into that if I have another failure. Was it enough power for your lights and signals? Have you tested it for any length of time as a replacement?
Thanks.

Chk this thread out to answer some of your questions. http://visforvoltage.org/forum/7698-xm-3000-xm-3100-dc-dc-converter#comment-44419

You wire the positive pack voltage as input to the power supply the neg to neg and the power supply output to the yellow wire under dash.
Everything you need is under the dash connected to the stock dc converter. Just replace it with the computer power supply. The dell that sparc 5 using it perfect. About $30.00 on ebay. Good Luck

Just like Bob says, sounds like you had multiple problems and when you said it got Scary BRIGHT, that is when the 16 volt Capacitor let loose. That says the switched mode converter went into failure to protect low voltage side. It made full output therefore popping the cap. There are two types of converters Cuk' and PWM types being the cheapest to manufacture. If the pass transistor fails there is full voltage on output caps and instant 60 volts on 12 volt side. As for finding low cost converters I found out from sparc that even voltages as low as 50 or 60 volts can make computer power supplies still work even though it says 50-60 hertz and 100-250 volts AC. I have been using computer power supplies on my EV's for many year but it wasn't till last month I tried what Sparc did use the eBay 12 volt converter on my XM-3000 and it worked just fine. My failure was H2O in unit and I heard it fry the next day after I got stopped for no lights. Some where on the list I have color code wiring if you want to use other brands of converters. Even using a spare 12 volt battery for lights.
Rusty

You will discover that about 99% of the time, a failure such as yours is due to multiple problems! Resistors do NOT just "self destruct" as a rule, they fail because somthing ELSE has failed, often a transistor or diode. Hitting the bump probably caused wiring to touch where it should not, blowing a transistor, which then caused an excessively high output voltage, which damaged the resistor and capacitor, so simply replacing the capacitor and resistor is not likely to repair your problem!-Bob

Yeah. In this case, the failure mode seems to be to put full buss voltage on the 12V out line :( :(
However, the power transistors look physically all right, and I thought it wouldn't hurt to at least replace the bad parts to see if it regained operation. It seems, however, that there's no one on this board that has opened a still-operating converter. I popped the electronic turn signal buzzer by connecting reverse polarity, and a RadioShack replacement transistor got it back in operation in an evening.

I am worried that the short caused by the bump DIDN'T occur inside the DC-DC, and that whatever I put in to replace it will get the same treatment once it's back on the road. It appears that the 12V and 48V busses are not isolated. I'm thinking of reviewing the wiring harness to see if it is possible to set up an isolated 12V system.

Mark

I would test the voltrage on your red 10amp fuse line along the bottom of the bike. It looks to be the coming from the dc converter as an output on the wiring diagram but when I tested it with a volt meter it had the full 72v of the battery pack. That would make it the input to the dc converter. If it shorted on the frame of the bike it might explain the dc converter shorting out.

Make CERTAIN that the BATTERIES are securely bolted down, and terminals insulated from contacting the frame,etc. when riding over rough surfaces, or their movement is likely to cause problems! Use heavy guage, good quality wiring, arranged to prevent mechanical stress or pinching and shorting. It is possible that something related to the batteries moved when you hit the bump, damaging your converter because of the intermittent short.--Bob

That's helpful. The ground path seems to be isolated from the frame, but under "high gee" conditions like a bump things may also be otherwise.

BTW, they got back to me the next day!

Mark,
The part you will want falls under part XB508-246 $26.
Feel free to give me a call to order.
Thank you,
Jonathan
402-603-4445 ext 202

They are on "banker's hours" for their phone service (10 to 3?), but I'll order the real thing tomorrow.

Yes Mon-Thur. but Jonathan did get the part right out to me. Less time then time quoted. I have had to wait over two months for a part, and yet other parts are here in a week. I have waited over a week for an American car part, a car in mass production. So to expect a Chinese part to be on you doorstep on demand is unrealistic. I have canceled orders with Extreme when I can get a part sooner (tire/tube) as I needed these parts as of today. But if we bad mouth and lose our only local source of parts, where are we then?
Most people that order these scooters do not have a clue as to how to maintain or service them.. I have seen a blown fuse put a scooter away until the batteries were dead, due to not charging ( because fuse was blown) Not that the batteries were bad before being allowed to sit for a year discharged. That Is why info on this forum can be so helpful. Such as keep your batteries charged whether riding, working or not.
(soapbox mode on)
With 5000 + miles on my 600, I am very pleased. It has held up to my expectations. It is a great way to get around town.
EVT is the way to go
(soapbox mode off)

What happen to the controller phase wires in the picture. How did they short out? They look like their is corrision.

ummmm isn't a red red black something more like 22 ohms?

Red, Red, Black IS the color-code for 22 ohms. Red=2, Black=times 0, brown=times10, red= times 100, orange=times1000, yellow=times 10,000 Green=times 100,000 and blue=times 1,000,000----------Last color in group of 3 is the multiplier(tells how many ZEROS to add), first two colors are digits to be multiplied.-black=1, brown=1, red=2, orange=3, yellow=4, green=5, blue=6, violet=7, gray=8, white=9--(Multiplier colors of GOLD or SILVER are used for resistors that are LESS than 10 ohms. Multiply by 0.1 for gold-(value is 1/10th) and multiply by 0.01 for silver (value is 1/100th) If there is a fourth band, it indicates the accuracy or precision of the resistor, with silver indicating +/- 10%, and gold indicates +/- 5% This is the standard resistor color code.--Bob Curry
PS:It is likely that whatever connected to that resistor may have been damaged.

duh Bob -- I hope who thought it was a 100 ohm reads both your post and mine.

You wire the positive pack voltage as input to the power supply the neg to neg and the power supply output to the yellow wire under dash.
Everything you need is under the dash connected to the stock dc converter. Just replace it with the computer power supply. The dell that sparc 5 using it perfect. About $30.00 on ebay. Good Luck

I'm trying to replace the dc-dc converter on my xm-3100 with the same dell sparc 5 power supply. Do you have any pictures of this wired up? I'm not sure I follow when you say neg to neg. I have three wires going to the existing dc-dc, positive 60v (nominal) from the battery pack, neg, and +12v. So, I would wire the battery pack positive to the input of the power supply, 12v+ to the 12v out on the power supply. What to do with the negative wire? Thanks in advance for any help.

Been awhile since I looked at this post. I don,t have pictures but what I was saying is the battery voltage is your input voltage to power supply. The black Negative is ground and the output is the output. Use a voltmeter to test all wires first. Then wire them as old dc converter was. I hope this helps.

Thanks for the reply. I can't seem to get it to work. I can measure 12v on the output of the power supply when plugged into the wall so I know it's functioning. However, when I wire the positive and neg wires to the power supply input I do not get anything from the output. Testing pos and neg wires with the multimeter yields +65v. Am I missing something?

Make sure you are using a switching power supply. If you are and it still doesn't work you should try a different power supply. Some will work with 65volts dc and some will not. Is it the same identical power supply sparc5 is using?

Yes, I believe it is the same power supply - a Dell DA-2.

What optiplex model is the power supply for. The one used for sparc5 conversion was sx280. There are several optiplex model power supply that are all DA-2 models.

Look at this site to see what I mean.

http://www.discountelectronics.com/index.php?l=product_list&c=5128

I hope this helps.

It is the same model used for the SX280, part# D3860. I'll give it another try today.

Update:
It did not work, I applied a load (12v light bulb) to the power supply. It works on AC power. When I connect the neutral (green bike wire) and +65v (yellow bike wire) I get nothing. Perhaps I am missing something. Can someone tell me exactly where to wire the neutral and +65v wires from the bike to the power supply (i.e. to each prong on the power cord or something else)? I may just give up and order another DC-DC converter.

When you test the yellow wire with the volt meter you get 65v correct? What wire are you using to ground the voltmeter? Whatever that color wire is that should be your ground wire. The 65v wire should be your power wire. If that isn't working then I am at a loss. You could send message directly to spark5 since he has gotten this to work in the past. Let me know if this helps.