HELP: ID this capacitor!

[teej]

I've come into possession of an old ECG DM-76 multimeter. The insulation on the test leads were hard as a rock and the battery was dated January 1998, so I know this thing hasn't been used in almost 20 years. I ordered a set of Fluke leads,  put a new battery in and the fuse tested OK, so I turned it on and got nothing. I opened the back panel and upon inspecting the components, I noticed the two large ceramic capacitors look like they exploded at some point. They read...

E
103P
SHC

I took the 103P to mean that they're 0.01uf with 100% tolerance, but I'm unsure about the "E" or the "SHC." Right now, I've got two of these in my Mouser shopping cart -- http://www.mouser.com/Search/ProductDetail.aspx?R=C323C103MCR5TAvirtualkey64600000virtualkey80-C323C103MCR -- but I'm not certain that they're what I need to get this DMM working again.

[Govmnt_Lacky]

I took the 103P to mean that they're 0.01uf with 100% tolerance...

100% tolerance?? Does that mean that it can vary from 0 to 0.02uF? 

The other letters on it are probably company logos and stamping codes.

[teej]

I took the 103P to mean that they're 0.01uf with 100% tolerance...

100% tolerance?? Does that mean that it can vary from 0 to 0.02uF? 

The other letters on it are probably company logos and stamping codes.

According to this source (http://wiki.xtronics.com/index.php/Capacitor_Codes), P means +100% and -0%

[italianguy63]

If the caps are indeed "exploded" as they look.  It probably took a huge overvoltage.  Probably a bit more wrong than a few bad caps... MC

[teej]

If the caps are indeed "exploded" as they look.  It probably took a huge overvoltage.  Probably a bit more wrong than a few bad caps... MC

I may just toss it then. If it was just a matter of a few components and test leads, I was hoping for a free DMM to replace my little Radio Shack one. Oh well.

[italianguy63]

Those caps are only a few cents each... no hurt in trying...

[KazooMan]

I'm not certain about the caps having "exploded" from just the one picture.  Those large diameter ceramic caps are really thin and bending them around the leads results in the covering material cracking just like in the picture.  They may actually be just fine.

Still, as was mentioned, they are cheaper than dirt.  Replace them and see where you stand.

If you do get the meter up and running again I would recommend comparing the readout with a known good meter before trusting the calibration.

[teej]

I'm not certain about the caps having "exploded" from just the one picture.  Those large diameter ceramic caps are really thin and bending them around the leads results in the covering material cracking just like in the picture.  They may actually be just fine.

Still, as was mentioned, they are cheaper than dirt.  Replace them and see where you stand.

If you do get the meter up and running again I would recommend comparing the readout with a known good meter before trusting the calibration.

See, that's what I was thinking, that they were bent and not exploded. I would think that if the DMM were overvolted, the fuse would have blown. I also forgot to mention that the screen doesn't display anything but the chip inside gets rather warm to the touch so I know it's getting power.

Would the caps I linked to work in this? They're MLCCs with the same capacitance and rated at 500v with 20% tolerance.

http://www.mouser.com/Search/ProductDetail.aspx?R=C323C103MCR5TAvirtualkey64600000virtualkey80-C323C103MCR

[gjcamann]

There's isn't anything magic about those cap values with 100%tolerance, i'd put in something close that you have on hand.

Even if it's a 1uF poly, or even leave them out all together and see if it works at all.

Just mind the voltage rating of the new caps and don't use the meter with anything over that.

[bool]

It's just a flux capacitor...

[greaser_au]

It's just a flux capacitor...

careful with the PCB cleaner, then...

david

[duck_arse]

I'd say the chip getting warm was a more likely stopper than the ceramics with the disturbed leads.

I have a meter, a goldstar, except for the case colours, looks identical. also dead, after measuring something on a laser tube. and that 1998 battery? sounds just about right for one o my fuzz boxes.

[Hatredman]

IT'S NOT A CAPACITOR!

http://en.m.wikipedia.org/wiki/Varistor

[bool]

they do look a bit like a varistor, but I ithink I see a cap "C-something" designator on the silkscreen and also a cap symbol "-||-" there as well ...

But yeah I have surely seen a couple of smaller varistors looking suspiciously similar to a hi-voltage ceramic cap. Crossed my mind a couple of times to use them as a "mojo" cap.

So, my diagnose still stays ... "it's a Flux capacitor"!


(reference: http://backtothefuture.wikia.com/wiki/Flux_capacitor )

[teej]

IT'S NOT A CAPACITOR!

http://en.m.wikipedia.org/wiki/Varistor

It is. The PCB is labelled with the "-||-" symbol for each and "C15" for the one in the foreground and "C1" for the one in the background.

[duck_arse]

I'm pretty sure my old goldstar has the circuit diagram included. I meant to remember (that's the key word, meant) to dive under the bed and fish it out of all the dust and fluff, see whether any similarities or not.

tomorrow.

[teej]

I popped a pair of 0.1uf (104 J) poly film caps in place of the 0.01uf (103 P) ceramic caps that were broken. I got the same results -- nothing on the display, chip got really warm and nothing else -- so I decided to send this DMM to the great tool kit in the sky. Actually, it's in my junk drawer (for now), but I kinda wish I hadn't bought those Fluke test leads now.

[duck_arse]

I got my old  meter out to compare. they are exactley the same, in as much as they both don't work. otherwise, they are completely different.

mine has digits, and counting and beeping, but the display ignores the input terminals. much peering through mag. glass under the display shows some metallic splatter of a wima 100nF. further investigations required.

you could hack a "this looks good and cheap" tester thing into your case, maybe.