Author Topic: TEKTRONIX TDS220  (Read 8579 times)

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Online tautech

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Re: TEKTRONIX TDS220
« Reply #50 on: December 21, 2017, 09:10:13 pm »
Christmas came a bit earlier than usual this year!  ;D ;D

All seems to be OK apart from one pixel in the lower right corner: neither always ON or OFF, just ... grey.
Can you spot it? Near the "CH1" from the trigger settings. No big deal of course!

 :-+
Cool, good fix.

Now two things to check with these models.
BNC input sockets break away from the mainboard PCB. They are not overly robust so be gentle with them.
There also was a factory recall for these scopes as early units could blow the ground trace between mains ground and the input BNC shells. Check there's conductivity between mains ground and the input shells. It's a safety issue.
If you check the Tek website there's a list of the SN#'s affected and if your unit has been fixed after the recall.
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Offline tacpaf69

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Re: TEKTRONIX TDS220
« Reply #51 on: December 21, 2017, 09:34:00 pm »
BNC input sockets break away from the mainboard PCB. They are not overly robust so be gentle with them.
Checked. Indeed, I've see other users doing different kind of operations to make theses BNCs a bit more solid.
On my scope, CH1 BNC was slightly loose, I simply re-soldered the joints with brand new solder. And while I was there, I also re-soldered BNCs for CH2 and TRIG.

There also was a factory recall for these scopes as early units could blow the ground trace between mains ground and the input BNC shells. Check there's conductivity between mains ground and the input shells. It's a safety issue.
If you check the Tek website there's a list of the SN#'s affected and if your unit has been fixed after the recall.
Sadly, one of the previous owner removed the Tektro tag from the back of the unit, where the SN was stamped.
As far as I understood, there's been a safety continuity from each BNC to earth on each and every single TDS 2x0 scope. But the problem from the earlier models was that this connection was ensured by a tiny track on the PCB that could easily get destroyed after a first misuse of the scope. And indeed, the BNC could then become a hazard in this case.
As far as I understood from a video I saw on Youtube about this issue (*), the "new" models have a metal tab added on the PCB. This little tab would create a contact from the big track on the PCB (where all BNCs are connected) up to the screen chassis, and then back to main earth.

I tested continuity from BNCs to main earth on my scope: all good!

(*)
« Last Edit: December 21, 2017, 09:41:02 pm by tacpaf69 »
 

Online tautech

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Re: TEKTRONIX TDS220
« Reply #52 on: December 21, 2017, 09:47:20 pm »
BNC input sockets break away from the mainboard PCB. They are not overly robust so be gentle with them.
Checked. Indeed, I've see other users doing different kind of operations to make theses BNCs a bit more solid.
On my scope, CH1 BNC was slightly loose, I simply re-soldered the joints with brand new solder. And while I was there, I also re-soldered BNCs for CH2 and TRIG.

There also was a factory recall for these scopes as early units could blow the ground trace between mains ground and the input BNC shells. Check there's conductivity between mains ground and the input shells. It's a safety issue.
If you check the Tek website there's a list of the SN#'s affected and if your unit has been fixed after the recall.
Sadly, one of the previous owner removed the Tektro tag from the back of the unit, where the SN was stamped.
As far as I understood, there's been a safety continuity from each BNC to earth on each and every single TDS 2x0 scope. But the problem from the earlier models was that this connection was ensured by a tiny track on the PCB that could easily get destroyed after a first misuse of the scope. And indeed, the BNC could then become a hazard in this case.
As far as I understood from a video I saw on Youtube about this issue (*), the "new" models have a metal tab added on the PCB. This little tab would create a contact from the big track on the PCB (where all BNCs are connected) up to the screen chassis, and then back to main earth.

I tested continuity from BNCs to main earth on my scope: all good!

Cool, you're all sorted then.  :-+

One I had the TH PCB pins on the BNC sockets were broken so I had to find replacements, again they were only two pin sockets so I scraped some of the PCB ground trace coating off and added a copper strap going up and over to make the BNC inputs as robust as possible.
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Offline Cubdriver

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Re: TEKTRONIX TDS220
« Reply #53 on: December 22, 2017, 04:56:40 pm »
Wow.  This turned out to be quite the thread!   :popcorn:

tacpaf69, I just wanted to say congratulations on your persistence and I'm pleased to see that you were able to get the 'unopened' scope back up and running.  Nice work!  :-+

-Pat
If it jams, force it.  If it breaks, you needed a new one anyway...
 
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Offline vishaldotgupta

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Re: TEKTRONIX TDS220
« Reply #54 on: January 08, 2020, 05:15:33 am »
Hi

i have couple of ADG322B chips ( 2 unused, and 2 pulled out but working) and few repaired displays for this scope

the displays had dark polarizers which were replaced, and are working ok.  Though not like new but still acceptable

Anyone interested, kindly let me know
 


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