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Keysight 3000T scope 1 GHz(or more) hardware upgrade mod
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Netroman:
I've just completed my mod (MSOX3024T now 1GHz) and it works great - many thanks to all envolved users from this Forum; especially Steve for additional hints and support.

If someone needs contacts, i got plenty of offers for the teledyne relays. Most where between ~40-59 US (i bought mine much too expensive and they are not very hard to get  |O).

For the really tiny parts i used a JBC NASE nano rework station - not cheap, but definitive worth the money. I did not believe that, but i'll never buy another brand anymore.

I had some problems with the user calibration, but the reasons were just wrong ordered parts. Especially the Driver "74ACT04" - MUST be an "ACT", because it is driven by Levels about 2.4 Volts and Needs to be able to work with TTL-Levels. So the "ACT" is absolute must (i had a "HCT" which has much too low power, whilst the ACT delivers up to 25 mA).

And i made absolute equal length cables for the calibration with 250mm (important: not longer than 300mm per cable), also bought hight quality tee-connectors bnc.

Though i was successful in reusing the desoldered cheaper relays, i would also suggest to buy new ones, because these should work for years without Troubles. I replaced the two ones in channel 1 whilst finding out my calibration problems.

Best regards from Austria, Josef
EE-digger:
Thanks for your report !  Now I'm stoked again to perform the mod.  I had a thought on clean shield removal.  What do you guys think about heating a single corner, sliding a piece of Kapton film under it, then on to the next 'til done?  Re-soldering should be a piece of cake but I might use NC paste to keep it neat.

Also, 74ACT is almost twice as fast as 74HCT.  Is this the cal signal?  The 74HCT rise time may have been inadequate.
TheSteve:

--- Quote from: EE-digger on June 02, 2018, 01:01:30 am ---Thanks for your report !  Now I'm stoked again to perform the mod.  I had a thought on clean shield removal.  What do you guys think about heating a single corner, sliding a piece of Kapton film under it, then on to the next 'til done?  Re-soldering should be a piece of cake but I might use NC paste to keep it neat.

Also, 74ACT is almost twice as fast as 74HCT.  Is this the cal signal?  The 74HCT rise time may have been inadequate.

--- End quote ---

Removing the shields isn't actually too bad. You can just lift them up corner by corner. The 74ACT04 drives the FET's that turn the Teledyne attenuator relays on and off.
EE-digger:
There must be some other loading on the '04 output then, that does not permit the HC04 to satisfy the Vgs.
Netroman:
@EE-digger: I broke a small piece of GND-route, because the shields do not really bend well. I suggest to spend some solder wick to remove as much as possible before you lift the corners. IMHO the corners do not lift (bend) more then 1/2 to 1 mm - that was not enough (too much solder on it and at first i did not use wick) in one case, so i ripped the route :-(

Josef
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