Black Onboard Chip Lost Info or Fuse Blown?

Ok now I know this isnt computer related but it is in a sense. My friend is actually studying to pass some dental tests in America. He is from abroad but needs to pass some tests to legally run his own business in the States. He borrowed a small dental solution mixing machine as seen here from another friend at a clinic:



Source: http://www.kerrdental.com/index/kerrdental-alloys-optimix-2

It's worth about $1500... & well he plugged it in and it was working fine for about 20 minutes. Than all of a sudden he also turned on another piece of equipment that uses a fair amount of wattage at the same time, on the same power strip. Something he had never done before because he would always run appliances independently by making sure other appliances were off on the same power strip. Turns out that after turning on the second appliance, and leaving the mixer on it duffed up the mixer. Now the mixer led screen shows "XXXXXXXXXXXX" [just the letters X across]. It lights up, just doesn't show the O/S as it would normally. The machine gets power, and seems to work, but the O/S isn't showing up.

He asked for my help since I know a lot about computers. In my opinion turning two high powered devices on at the same time, on the same power strip. Probably caused a brown out dip in electrical current which wiped the O/S from the black onboard nand chip/rom chip or what have you. I referred to the manual and all it said about a non working display is to check the fuses. Mind you the screen isn't blotchy, isn't damaged to the eye, it's just not showing the operating system only the letter "X' across the whole screen.

This is what the screen would normally look like working:



I took the fuses out and they seem to be fine. They're not charred, and the wire isn't melted, or broken away/separated. It does seem as if the wires in both fuses are somewhat slanted, but they look like they're connected on each end of the fuse correctly.

The two fuses are rated 0.63A 250V for 115/120V American Standard use, and look kind of like this with the wire slanted in the middle:



As you can see the wire in the google example is slanted but still connected. The photo below is a style of fuse I have usually seen with the wire directly centered in the middle:




I took the unit appart, and it's fairly basic looking inside compared to a computer. It looks like basic calculator style parts lol [jokes]. Anyways there is no charring on the internal motherboard, capacitors look fine, and the unit powers on as I said before. I think the unit lost the O/S in during a power fluctuation. That' my opinion... I have lost the onboard rom/nand O/S off an external hard drive enclosure before. Though I was lucky enough to find it through google and flash it back to the external enclosure. Which worked! But this is a dental device and you won't find that online, nor will you find a way to connect it to a pc obviously.

So my questions are:

1. What do you think happened?

2. Could buying two new fuses make the unit work? If so what are the chances percentage wise?

3. I know little about fuses, but from my understanding if one is done for the wire would be melted, or split. Could it be semi functional yet still power the unit? I wouldn't think a semi damaged fuse would even allow power through.



Thanks


Any help for this $1500 mess would be helpful.

 

if the systems power on then it is most likey not the fuse, but get a cheap multimeter and test the fuses or it may be cheaper to just buy replacement fuses and see if that is it.
If you get a multimeter set it for continuity and place a probe on each end and if it beeps, they are good fuses, if not...

 

There are only two fuses. I didn't see any inside the actual unit. The manufacturer wants us to send it in in order to make money [$300]. They didn't even tell us to check the fuses. Which goes to show that they just want money. I Tried putting the fuses in opposite positions but it does the same thing [Ie: left one right, right one left]. Unit powers on, yet the LED screen shows the letter "XXXXXXXXXXXX" <- like that when you turn it on. The screen lights up though...

I just opened it up again to double check if there were any extra fuses on board, apart from the two that come out of the removable tray behind the machine. Well everything inside looks completely fine. I guess the brown out in electricity duffed up something somewhere. You can still input settings on the keypad and the machine still works. You just can't see what settings your pressing on the LED screen.

After you turn the machine on all it does is say "XXXXXXXXXXX" on the screen, and that goes away after about 3 seconds. The screen does stay lit up green though as I mentioned before. The unit is actually discontinued when I looked into it just now [not surprised]. The manual states a date of 1999. Darn thing was supposedly bought new and never used though. Until he used it... I have no meters to test any continuity, and such. I guess it's either use it without the screen telling you what settings your on [which
is hard to do]. Or just find another one...


Thanks again

 

It is very rare for a "fusible element" to be blown but not be apparent. Those two fuses look perfectly fine and indicate there was no "short" in your device that caused an excess amount of current (and thus heat - blowing the fuse).

Slanted fusible links are common - often done intentionally - it is just manufacturing "style".

Therefore, it would seem another device has failed - my guess, by your description of the events leading up to the failure, is the power supply, or related regulator circuits.