Products > Test Equipment
Test Equipment Anonymous (TEA) group therapy thread
DC1MC:
OK everybody, not one but TWO :wtf: shameless shilling:
1) Due to some interest in the last AR488 GPIB buffered interface I have somehow three persons asking for it :scared:, so I had to order another set of PCB to make everybody happy, that means that 8 are still available either as blanco PCB, or assembled and tested and for the reason that JLPCB works during the Chinese New Year holiday the order will reach me early next week :clap:, so if you still don't have a GPIB adapter for your TEA and not flush with money to get Prologix or NI, now is the moment to pounce if you're in DE, or around.
2) The more important for me, I'm planning to do an improved Arduino Nano compatible board, plus something that is now not coalesced yet completely, I have created a thread here:
https://www.eevblog.com/forum/projects/improved-performance-5v-arduino-nanomega-compatible/
Kindly please read and give me your opinion or even contribute a bit.
Cheers,
DC1MC
Vince:
TEK 7603 restoration
--- Quote from: TERRA Operative on February 01, 2023, 11:32:05 pm ---
See if this mod is installed and try it if not.. Apparently it reduces the fuzzyness which is a GHz range oscillation. It might help a little.
Shouldn't need much more than a bit of copper or brass strap.
https://w140.com/tekwiki/images/0/0e/7603mod36005.pdf
--- End quote ---
Thanks !
So Tek was aware of the problem... yet they put that scope on the market anyway :palm:
The guys in the marketing dept must have told management : " We have a narrow window to launch these new 7000 series of scope , it's NOW and not in 3 months ".
... "You can always improve it later, but it needs to go public NOW ".
Oh dear..
That board is easy to access from the side of the chassis, once you remove a large access door, so I had a go at it.
So I added a strap, well two, because the one shown in the Tek illustration is super wide, don't have that.
Best I could come up with in a hurry was to find a use for my 35 year old 15 meter roll of 3mm wide tinned solder wick !
Too coarse to work on your average electronic board, and too much of a thermal mass for my 50W iron to heat it up quickly.
So I put two pieces of braid in //, each insulated with heatshrink tubing. Blue tubing of course, because.. it's a Tek ! ;D
I don't know, I felt in the mood of using some colour..
Given how old that braid is, needless to say solder doesn't stick to it any more... but if you heat it up long enough and use enough of ym long expired 30cc syringe of flux... you can bring it back from the dead...
So the result ? Well, scope still works and no smoke, so that's a good start. I would need to male a side by side comparison to be objective.. Which is not possible of course.
So I have to go with my memory here, of what it was like before I put the straps in place. I would say it's better. Hardly "Tektronix sharp", but better enough that I think it exists and is not a placebo effect. So I will take that... thanks Terra for the link.
I also noticed that the display at power up does not move and up erratically any more... well it might come back later who knows, but for now I don't see an ounce of it any longer, so I will take that as well ! 8) We will see in the longer run.
Maybe the various connectors just needed to be reseated / cycled..
--- Quote from: TERRA Operative on February 01, 2023, 11:32:05 pm ---Also replace more caps! :P
--- End quote ---
I found 4 electrolytic caps on that board. No alu ones, but 4 dipped tantalums, the old variety with colour bands and dots on them. All the same value it looks like, though I don't know what value that is... need to google how to decode the markings. So I could replace those I guess.
--- Quote from: TERRA Operative on February 01, 2023, 11:32:05 pm ---And check for drifted high value carbon composite resistors in HV circuits and replace as needed (I replace almost all carbon composite resistors with metal film by default these days, besides those in HF signal path where some care is required).
--- End quote ---
Will look at the HV section later on, but I fear it might not be feasible as access looks to be... impossible. I mean I can't even SEE where the HV stuff is located in that chassis ! :o That's definitely not promising to me...
23H45.... :=\
tautech:
--- Quote from: Vince on February 02, 2023, 10:46:34 pm ---
I found 4 electrolytic caps on that board. No alu ones, but 4 dipped tantalums, the old variety with colour bands and dots on them. All the same value it looks like, though I don't know what value that is... need to google how to decode the markings. So I could replace those I guess.
--- End quote ---
:-//
Don't you have the service manual with the BOM ?
Brown, Black, Green should be 10uF....measure one.
Vince:
No it should be 1uF not 10 ! ;D
Schematic confirms it, all 1uF to decouple the 4 rails that power that board : +/- 50V and +/-15V.
tautech:
--- Quote from: Vince on February 02, 2023, 11:13:30 pm ---No it should be 1uF not 10 ! ;D
Schematic confirms it, all 1uF to decouple the 4 rails that power that board : +/- 50V and +/-15V.
--- End quote ---
:-+
Just be sure to derate them all with 50V tants. Quick rule of thumb for tants is to at least double the rail rating for the cap itself.
You might remember some older Tek stuff used 15V tants on 12V rails which was a really common failure point and our old buddy bd139 made lots of coin buying particular old Teks with this common fault.....like a 5 min fix.
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