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Electronics => Repair => Topic started by: lanza2005 on December 23, 2021, 10:23:04 am

Title: Repair Tektronix 2467B, A5 SMD version board
Post by: lanza2005 on December 23, 2021, 10:23:04 am

I have a Tektronix 2467B, with problems on the A5 board. As usual. The open capacitors and the liquid, through the plate. After changing them, the TRACE is only visible when I move the INTENSITY knob and then disappears. Can you advise me, where to put my hand? Thank you very much and greetings.

Title: Re: Repair Tektronix 2467B, A5 SMD version board
Post by: lanza2005 on December 26, 2021, 02:30:57 pm

IMG

Title: Re: Repair Tektronix 2467B, A5 SMD version board
Post by: lanza2005 on December 26, 2021, 02:36:51 pm

The capacitors are already changed and the tracks checked. Clean the plate with 96º alcohol. Also the capacitors of the power supply. Any advice? Thank you.

Title: Re: Repair Tektronix 2467B, A5 SMD version board
Post by: Joust on February 26, 2022, 02:59:32 am

i just got a 2467b as well
Its doing almost the same thing although mine stays on for a few seconds after touching the knob to refresh screen.
i haven't opened mine at all yet but was searching for similar problems.

dont know if i have SMB board or not yet. hoping not because i have no reader to get sram data out of dallas chip.

Can anyone offer advice to Lanza?

Title: Re: Repair Tektronix 2467B, A5 SMD version board
Post by: jxjbsd on February 28, 2022, 03:58:46 am

https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/ (https://www.eevblog.com/forum/testgear/tektronix-2465b-oscilloscope-teardown/)
Go to this thread to ask questions.

Title: Re: Repair Tektronix 2467B, A5 SMD version board
Post by: grumpydoc on February 28, 2022, 08:20:35 am

The grid bias adjustment looks to be off.

Any errors on start up? Especially test 04 fails?

Your repair seems to be missing some components, notably the potentiometer used to adjust the DAC reference current (and hence output) and an associated resistor R2015

When cleaning PCBs I use a 1/2" paintbrush with the bristles trimmed down to about 7/16" (i.e. about 1cm) - something like that would do much less damage to the silkscreen than whatever was used on your PCB.

Title: Re: Repair Tektronix 2467B, A5 SMD version board
Post by: jonpaul on February 28, 2022, 11:16:28 am

Bonjour, Normally  A5 SMD cap leakage (there are may of the caps) damages nearby components and eats internal traces on the PCB. The fluid causes the copper to becone unslderable, give away i a odd smell on heated traces and joints.


Suggest  a very deep inspection, removal all affected parts. Total clean of board, check trace continuity.

If the DAC and REF ckt is not perfect,  all sorts of control oddities, as the scope is "fly by wire"

See very long threads on this in the old 2465B teardown, also excellent Groups.io TEKSCOPES, and TEKSCOPES2
ask there, many ex TEK experts.

https://groups.io/g/TekScopes/topics
https://groups.io/g/TekScopes2/topics

Bon Chance,

Jon

PS:  A5 had the notorious Dallas 1225 NVRAM with dying /dead Li batter that holds all CAL.