I fried my ESR Micro 3.1 ...

[lkvee]

... by placing leads on a CapXon capacitor inside a Viewsonic VG2021m.

Four other capacitors were bulging. I put the leads on the one CapXon that wasn't bulging (1000uF 25V).

I saw sparks.

I yanked the batteries and let it sit for a while, but I still fail to get any readings from known-to-be-good capacitors. Capacitance is always zero and there's no ESR readings (all dashes).

I put in an order with "Russian Mike" for another one.

I don't think there's any hope for my meter, and I'm posting here just to be sure.

Ugh.

[ipman]

Re: I fried my ESR Micro 3.1 ...

If my memory serves me well, there are two back-to-back diodes at the input.
Check them, one of them maybe shorted.

[lkvee]

Re: I fried my ESR Micro 3.1 ...

Here are two pictures. I hope they confirm what you'd like to investigate further. I've just been told my order won't be fulfilled/sent until the beginning of September, too.

[seanc]

Re: I fried my ESR Micro 3.1 ...

Those two black rectangles to the left of the cables are probably the diodes ipman was referring to. Are they shorted?

[ipman]

Re: I fried my ESR Micro 3.1 ...

Never seen this one in particular, but most ESR meters have two back-to-back diodes at the input for protection against charged caps.
seanc indicated the two SMD diodes at left, and most probably he's right. Check them for shorts.
You can even remove them, but this will leave you without protection and at the next mistake ... you will need a new one for sure. And considering that Michael is not delivering anymore these devices ... take care of what you have.

[lkvee]

Re: I fried my ESR Micro 3.1 ...

I'm trying to test the diodes with a Cen-Tech meter from Harbor Freight (Item 92020).

Manual's here and I followed the directions for diode test:
http://www.cyberpoet.net/ebay/centech.html

I'm not sure if I'm using the meter correctly. I got voltage drops of about the same magnitude REGARDLESS of polarity of the leads. The numbers hovered about high-500's to low-600's.

[Krankshaft]

Re: I fried my ESR Micro 3.1 ...

If you get a voltage drop in both directions the diode is shorted.

You may have to desolder them from the circuit to test them.

See these micro meters are all nice and cool until you have to perform repairs . I'll keep my through hole version thanks .

I hope you have some SMD soldering experience.

[lkvee]

Re: I fried my ESR Micro 3.1 ...

I've been planning to do some surface-mount soldering, but it was actually for a 208-pin QFP on a TV instead of my ESR Micro.

I guess I should be buying some soldering paste as well as the diodes from ... DigiKey and Mouser?

[Krankshaft]

Re: I fried my ESR Micro 3.1 ...

Never used soldering paste extensively just tweezers. The 3-6 month shelf life turned me off early on. I just use a well tip for QFPs and drag it across the pins.

To remove flow some extra solder on each end of the component. Then melt one side pull it up gently with tweezers just enough for it to clear the solder on the pad. Grab the component then melt the other side and it will lift off.

Clear the pads with wick or a solder sucker.

Apply solder to one pad put the device on top press against it with the tweezers melt the solder it drops onto the pad then solder the other end.

[lkvee]

Re: I fried my ESR Micro 3.1 ...

The Curious Inventor video comes to my mind. Thanks for mentioning shelf-life for solder paste. I still think I may need it for surface-mounted capacitors, but that's yet another TV project.

Nice to know you're in NJ, too. I'm in Morris County.

[severach]

Re: I fried my ESR Micro 3.1 ...

For back to back diodes the same voltage drop in both directions is what we expect. Near 0.500v in both directions means neither the diodes nor any parallel device is shorted. If the diodes are shorted there's no need to remove them from the circuit. They will read shorted in both directions. The diodes would need to be removed to determine whether they are shorted or something else.

I recommend some SMD practice on smaller devices before tackling a 208 QFP.

[lkvee]

Re: I fried my ESR Micro 3.1 ...

I was looking forward to some surface-mounted work!

What else should I examine? I'm still getting zero for capacitance and non-readings for ESR. Looks like the logic chip's OK. I even tried putting capacitor leads directly on the board (where the probe wires are connected), but I'm not sure if I made a good-enough connection.

[ipman]

Re: I fried my ESR Micro 3.1 ...

Weird. If the cap was charged, these back-to-back diodes had to discharge the cap. Any voltage drop exceeding the diode forward drop voltage should have opened one of the diodes and short the cap leads, protecting the rest of the ESR meter.
But your readings show that diodes are good. To be sure, remove them and measure them individually.
If you want to try, put that capacitor at the diodes terminals or afther, even better: remove the diodes and measure without them.

[tron]

Re: I fried my ESR Micro 3.1 ...

http://www.radiodevices.info/repair.htm

[PCBONEZ]

Re: I fried my ESR Micro 3.1 ...

You must remove back-to-back diodes to check them.
Diodes do short.
You have to have a high one way -and- a low the other way to know they are good.
Can't check both with another diode in reverse parallel.
.

[goodpsusearch]

Re: I fried my ESR Micro 3.1 ...

Did you try to recalibrate it?

[popeye]

Re: I fried my ESR Micro 3.1 ...

I was looking forward to some surface-mounted work!

What else should I examine? I'm still getting zero for capacitance and non-readings for ESR. Looks like the logic chip's OK. I even tried putting capacitor leads directly on the board (where the probe wires are connected), but I'm not sure if I made a good-enough connection.

My advise is look to the post 2 down from your one from tron!!!

[lkvee]

Re: I fried my ESR Micro 3.1 ...

Turns out my 1 Ohm resistor was open. It did its job very well as a fuse, and now I must replace it. The only other number I ne to follow is "0805".

Still having trouble finding which particular item to buy from DigiKey or Mouser. Many of these line items require a minimum purchase of 5000 units, but I may need to go that way.

[brethin]

Re: I fried my ESR Micro 3.1 ...

Please tell me you didn't just say you may need to buy 5000 units just to get a 1 ohm resistor.

[ipman]

Re: I fried my ESR Micro 3.1 ...

Look for that resistor on a dead motherboard. You can be lucky and find one.