Tektronix TDS210 teardown and BNC replacement

[bd139]

It’s a forum quoting fail.

[mnementh]

Hmm, something is going awry here I'm being credited with quotes that I never made, nobody ever credits me with anything useful, like money in the bank 

It’s a forum quoting fail.

fixed.

mnem

[Specmaster]

Thats a pretty full bag of them..........run..........take cover............

[mnementh]

Thats a pretty full bag of them..........run..........take cover............

That is actually my real life kit that I use; 90% of my calls are easily handled with what's in that bag. For other calls I add my cordless drill/impact bag and/or my networking bag.

Maybe one client in a hundred notices the little tag... I just waggle my finger and make a sly grin & "shush" gesture when they do. 


mnem
It doesn't eat much... 

[Specmaster]

Don't look now but I feel that paint brush may have expired and needs urgent attention or maybe replacing 

[mnementh]

Don't look now but I feel that paint brush may have expired and needs urgent attention or maybe replacing 

Naaah... that's the one I use for all my grunge work; it always looks like hell until it gets so filthy I can't clean it. You can't see the 2" natural bristle paintbrush under it that I use for dusting after I knock all the nasty stuff loose with that 3/$1 one.


mnem
The right tool for the job.

[bd139]

Quick note. Recap list for the supply.

Only for supply labelled SW422 by Ault Korea. Nice liitle power supply. Really good quality bit of kit.

Code: [Select]

C= capacitance (uF)
V= voltage (Volts)
T= Temperature (oC)
D= case diameter (mm)
P= Pitch (mm)
B= Brand
S= Series
Z= purpose

C3          -> C=68   V=450 T=105 D=22 P=10 B=Nippon S=KMG Z="primary filter"
C6          -> C=22   V=35  T=105 D=5  P=5  B=Nippon S=SXE Z="primary SMPS controller filter"
C10         -> C=2.2  V=50  T=105 D=5  P=5  B=Nippon S=SXE Z="secondary TL431 feedback decoupling"
C11,C12,C13 -> C=2200 V=6.3 T=105 D=12 P=5  B=Nippon S=SXE Z="secondary filter"
C14         -> C=2200 V=6.3 T=105 D=10 P=5  B=ELNA   S=RSH Z="secondary filter"
C15         -> C=470  V=6.3 T=105 D=10 P=5  B=Nippon S=SXE Z="secondary filter"
C16         -> C=22   V=35  T=105 D=5  P=5  B=Nippon S=SXE Z="secondary decoupling"
C17         -> C=4.7  V=50  T=105 D=5  P=5  B=Nippon S=SXE Z="secondary decoupling"
C21         -> C=47   V=16  T=105 D=5  P=5  B=Nippon S=SXE Z="secondary HV osc decoupling"

Notes:
- Nippon KMG 200mA ripple current specified
- Nippon SXE/ELNA RSH are low ESR


[Specmaster]

Does this mean that you're doing a fully recap of the PSU on the 210 then? Mine (when it arrives) is older than yours so I suspect I ought to consider re-capping that as well. It seems impossible that the 210 has been around for 21 years but that what the data suggests?

[bd139]

I’m replacing the secondary filter caps only. There’s a little bit of noise on low mV settings. Primary and ancillary caps are all probably fine.

210 has indeed been around for 21 years. Mine is 18 years old looking at the date codes.

[Specmaster]

Will the Rigols etc be around that long and still be working like new?

[bd139]

I doubt it. See: https://www.eevblog.com/forum/testgear/rigol-red-screen-of-death/

[Gyro]

Will the Rigols etc be around that long and still be working like new?

I doubt it. See: https://www.eevblog.com/forum/testgear/rigol-red-screen-of-death/

There is (or was) a difference between minimizing production cost with a professional industrial environment target market, and minimizing production cost full stop.

[bd139]

Exactly that.

[bitseeker]

I doubt it. See: https://www.eevblog.com/forum/testgear/rigol-red-screen-of-death/

Interesting. Bad flash memory.

[bd139]

Yep. It’s also BGA packaged so BER straight away.

Also one TDS210 encoder cost more than all the encoders on a DS1054Z

[bitseeker]

Oof! BGA. Not a repair for the hobbyist.

[tautech]

I’m replacing the secondary filter caps only. There’s a little bit of noise on low mV settings. Primary and ancillary caps are all probably fine.

Please take before and after recap pics.

[bd139]

I shall indeed. SOP here.  Probably nothing will change but will be interesting either way 

[tautech]

I shall indeed. SOP here.  Probably nothing will change but will be interesting either way 

Yeah, just a little sanity check for you. 
Do measure the old caps too for ESR and uF.

[Specmaster]

That should be interesting....

[tautech]

That should be interesting....

If PSU rail ripple are still within spec I expect nothing will change.....traces will still show some noise on mV/div settings. It's a DSO and you can't get away from that.

[Specmaster]

I can with my Fluke 3390B, just dial up a high number for the averaging, smooth as a babies bum 

[bd139]

Yes I expect noise at lower signal levels.

However I don't expect a roughly 15KHz signal

You can change the persistence and the averaging on these scopes. That does indeed make the noise go away mathematically.

[Specmaster]

Straight DSO



Averaging switched on

[tautech]

Yes I expect noise at lower signal levels.

However I don't expect a roughly 15KHz signal

Is the PSU switcher frequency 15 KHz ? Seems a bit low but not outside the realms of possibility.

You can change the persistence and the averaging on these scopes. That does indeed make the noise go away mathematically.

More modern DSO's have even more tools to clean up traces however when when talking about displayed noise we should only compare apples with apples and only use normal input settings.
Sometimes that's impossible for low mV/div settings as many DSO's go into 20 MHz BW limit mode automatically to reduce displayed noise.