Part ID not related to pedals.

[JakeFuzz]

One of the guys in my lab blew the good handheld Tektronix multimeter. I think I've tracked the problem to one burned out component that appears melted and registers a different resistance than the other two similar parts in this meter.

Here is where I am stumped. What on earth are these things? They look to me like big box capacitors but I am not quite sure. The only marking they have on them are a T inscribed in a circle on the very top, Mousers brand list that start with T's don't turn up anything on this symbol. The silkscreen acronym is SG while all the caps and resistors have the standard R and C. The only thing I can find is Stacked Gold and that doesn't seem right. I am hoping someone has come across this part or seen this brand symbol before. I swear I've seen this symbol before on an old Tungsram transistor but it couldn't be the same. Thanks!

[madbean]

Can't say for sure. I bet someone on FSB or DIYSB could identify it though.

[gtr2]

I would think you should be able to find a schematic somewhere for that.  I've got an old free Tektronix oscilloscope that needed fixed and I found a schematic without to much trouble on the web.  Tektronix documentation is impressive on their gear.

Josh

[JakeFuzz]

Can't say for sure. I bet someone on FSB or DIYSB could identify it though.

Yeah Ill try and post it over there too and see if people know what it is.

I would think you should be able to find a schematic somewhere for that.  I've got an old free Tektronix oscilloscope that needed fixed and I found a schematic without to much trouble on the web.  Tektronix documentation is impressive on their gear.

Josh

I told the guy to email Tektronix and ask for a schematic but the person says they don't have a schem (or just wont give us one) and they have cut all support for this product.     Ill continue the search online...

[gtr2]

I had to join a yahoo group to find mine. TekScopes was the group.  I do think they have other schematics on there.  I could take a look if you have the model.

Josh

[JakeFuzz]

I had to join a yahoo group to find mine. TekScopes was the group.  I do think they have other schematics on there.  I could take a look if you have the model.

Josh

That would be awesome. It is a Tektronix DMM254, looks pretty old. Thanks Josh.

[JakeFuzz]

Woah, hold on. I got into the lab and unsoldered this part form the board. The yellow thing is just a shrink on plastic cover!  

Underneath is a Taiyo AG20, a ceramic resonator and it is definitely the problem because it is all burned up. Awesome, strange i've never seen covers like this before. I am wondering if it is there to prevent the part from damaging other components on the board in case it fails. Very cool, thanks for all the help guys!

Edit: Hmm nope looks like it is something called a spark gap, used when the input voltages are too high to protect the circuit, sort of like a fuse for open circuits.

[Haberdasher]

Spark Gap, so thats what SG is.

I was scavenging parts from a couple of old CRT monitors a while back and saw some on those boards.  They were axial and looked just like glass germanium diodes but they had no readings.  Makes a little more sense now.

[gtr2]

Glad you made some headway.  I couldn't come up with anything on the meter.

Josh