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I have a burned diode with no markings any direction? Answered

This analog multi-meter has a bad diode I cannot identify. Can anybody help?



2 months ago

This person has asked if anyone knows how to identify this diode.

NOT how to go out and buy a whole new device.

Some people fail to help when all they can offer is to buy new and throw away. Need more free thinkers in this world.

Those resistors nearby the diode are precision resistors, and i will BET some of them are fried also! The meter is TOAST. it is not worth repairing. If you go to harbor freight tools, they sell a DANDY little digital voltmeter for FOUR dollars! With the DIGITAL meter, you can make mistakes like measuring VOLTAGES when the meter is set for OHMS! you cant do that EVER.... not even for ONE SECOND using an analog meter. thats very likely what happened to your meter. Unfortunately, it is also very likely that the METER MOVEMENT (pointer mechanism) is burned out also. you can check that by using a GOOD meter set to the OHMS function. touch probes to the meter movement terminals...and see if meter needle deflects at all. if it doesn't, the meter movement is also toasted. FRAMISTAN...

Why not take a trip to your local electronics components store and see what they say? I imagine it's going to be rated at the highest voltage that your multi-meter is designed to take. Other than that, I'm quite at a loss. btw a new multimeter costs just a few quid - seriously - would you want to spend on a diode where safety has already been compromised? (ie other componenets may also have been burned but you cannot see it). It's a sad reflection on our throw-away society, but I'd rather do that than expose myself to any needless risk.

Replace the meter, scavenge the old one for parts? The meter itself (the dial) is likely still good...

have you noticed above the sears logo it says "fuse and diode protection" pmsl! maybe you can just take it back to sears as it is and ask for a replacement? or try www3.sears.com and www.sears.com


8 years ago

Looks like a plain old diode to me. Try a 1n4007 in there.

You must have checked 110 with the ohms setting on. You must not still have the manual do you? It probably has a diagram in the back, but they don't usually identify parts very well. Use those two diodes next to where the burned one was. It might be the same type. Go to RS and buy several different kinds. Try them in the circuit and see if you get lucky. Are there any other numbers? I couldn't find anything using the number on the front. You can get manuals from Sears for almost everything they ever sold.

At a guess, from looking at your pictures, it's another one like the two just below it on the PCB. Note the bit of yellow "goo" atop the missing diode's graphic on the PCB. It almost appears that the diode's marking came off onto the PCB when it failed.

It almost looks like a fuse...but there's a replaceable fuse already in the unit. really peculiar. Can you highlight on the unit where it came out of? I'm guessing the 'burnt looking section with no component in the 2 holes'.

It appears to be the area at the upper right hand corner of the PCB

I also notice the pcb is heavily (and usefully) marked with component values (look near the resistors) - what markings are near where the diode used to be?