Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
mnementh:
--- Quote from: BravoV on May 31, 2018, 08:24:07 am ---
--- Quote from: bd139 on May 31, 2018, 08:14:34 am ---Just a point on the EMI filters on these. The little silver box actually contains 2/3 RIFA X2 capacitors and a common mode choke usually. RIFAs are pretty bad on their own but when you put them inside a pipe bomb, interesting things happen. We had one much newer than that in a SAN power supply and it blew its load all over the inside of the unit. I have a photo somewhere in the office I will dig out but it was a right mess.
--- End quote ---
Please do, it will be a good reference for motivational photo. ;D
--- End quote ---
Or at least a good storyboard frame for an episode of "Robot Chicken"... :-DD
--- Quote from: bd139 on May 31, 2018, 09:53:09 am ---Doesn't mean it's not going to blow up :(
I had another vendor's one blow up in a Philips scope. Hissed like an angry snake. Fortunately it was burning in with the case open on the table so I got to shut the power down before it went.
They are replace on sight "if older than 20 years" disposable parts really. We're way beyond the design life.
Might be worth checking temperature of it after an hour or so. That's a good indicator. They don't run hot unless there's something wrong with them.
--- End quote ---
Interesting... the filter circuit in that video appears to be a common mode choke and some caps as a 6dB low-pass filter; guessing by that one around 0-300Hz or so is typical?
It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.
But on the flip side, this might be an opportunity to easily upgrade to a multistage model with better EMI and even added RFI filtering; when these 'scopes were made, the 1GHz + background noise that permeates any even marginally developed geolocation simply did not exist.
Thanks for shining a light on this mostly-overlooked aspect of our addiction! :-+
mnem
Mornings are not for the weak.
tggzzz:
--- Quote from: mnementh on May 31, 2018, 01:20:15 pm ---It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.
--- End quote ---
It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.
Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter :)
mnementh:
--- Quote from: tautech on May 31, 2018, 09:58:54 am ---
--- Quote from: med6753 on May 31, 2018, 09:49:16 am ---I am confident that the EMI filter in the 2465 is not made by Schaffner.
--- End quote ---
Seems so as the mains filtering is on another PCB.
Shown here:
https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/msg425034/#msg425034
--- End quote ---
The 24xx family used both with and without, just like the 22xx family. But you knew that. ;) Here's a pic of another 2465B (Above left) from the same thread that DOES have an IEC Socket EMI filter. It still has the same filtering circuit in the A2 DC-DC board. The 2230 has a separate EMI filter board, but mine (above right) also has the IEC EMI filter; I've seen photos of other 22xx scopes with just a plain IEC socket.
mnem
*Back out into the suck*
mnementh:
--- Quote from: BravoV on May 31, 2018, 01:10:20 pm ---
2.5GHz thingie, not my fault, blame Berni. :palm:
--- End quote ---
Don't take this the wrong way, but...
SCHWANNNGGGG!!!
mnem
Morning wood is the BEST kind. :-DD
mnementh:
--- Quote from: tggzzz on May 31, 2018, 01:27:00 pm ---
--- Quote from: mnementh on May 31, 2018, 01:20:15 pm ---It appears there are about a zillion different models available in any given form factor (looking at the Schaffner site which has lots of reference packets to educate yourself with); We could have some headaches if we don't select carefully.
--- End quote ---
It becomes interesting when you want to replace the input filter in a 1982 Solartron 7081 8 digit voltmeter - because it also contains a fuse and a rather complex voltage selector.
Fortunately Schaffner still make the same type (+1 Schaffner!), so the only pain is that it cost about half the price of the voltmeter :)
--- End quote ---
Yeah, that's where it becomes worth the arseache to disassemble the damn thing and repair it, I'd think.
With all due respect to the 7081, I am quite thankful to be able to cling to THIS side of the voltnuttery line. :phew:
mnem
But it is SUCH a slippery slope... :-DD
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version