Hi Albert,

Thank you for posting your well written write up. The clear pictures and explanations are very informative and are sure to assist many Tektronix owner’s around the world.

I am even more grateful for not having to translate anything!

I have just recently acquired my Tektronix 2465 cro after confirming the existence of such a helpful bunch of people like yourself, who are willing to share information and assist on-line with their experience and knowledge.

My scope also has the notorious Rifa caps, one of which clearly indicates failure and leakage as well as signs of a resistor’s catastrophic failure.

After opening the item, I was daunted by the prospect and potential for damaging other components. Discovering your write up has provided some encouragement for me to undertake the project challenge.

Are there any other parts that you would suggest replacing while the machine is dismantled?

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My 2465 just blew its A2C1016 capacitor and the A2R1016 resistor.
Loud bang followed by awful smell !

Thanks to your article, I will be repairing my scope instead of recycling it.

John

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Update: Programming the RAMTRON FerroMagnetic FM16w08 chips with the brandnew TL866II is simply impossible! Although they are supported in the device list the universal programmer sadly kept giving at least 24 verify errors. And also a second brandnew FM16w08 failed in the same way!
Luckily my RT809H was completely capable to program, read and verify both memory chips! But only after I upgraded the windows program to version 20210222. Because previous RT809H version only supported the FM1808 type.

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PS2: there is no need to remove any of the databuffer chips or the CPU to be able to read the data in the 4464 SRAM because if the scope is powered off there is no address or databus line conflict since at this moment the Sram will be the only functioning component in the 2465A (or the 2440 or other equally designed Tektronix) scope!

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Today 10 April '21 I was successfully able to copy the 4464 8192Bytes (8K) SRAM in my Tektronix 2465A oscilloscope that also contains all Calibration data.
I modified my 28 pin testclamp with 28 pins socket and used my TL866II as 27c64 eprom reader to extract the content of my RAM as bin copy. Simply by adding a 1N4148 diode to Vcc of the 28 pins socket this way accidentally avoiding losing the backup lithium voltage on pin 28 of the 4464 static RAM while starting to read it. And added two 100 ohm resistors to pin 27 (/PGM) and pin 26 (CE) to prevent accidentally writing instead reading the SRAM. (those wires from testclamp to the 28 pins socket can be left unconnected). But therefore you also disable the pin contact test in the TL866II program and do not need the chip ID check either. And after reading the Ram also verify it to make sure it was read correctly without errors! I already ordered 2 FM16w08 special Ferromagnetic RAMs that never lose their data even without any Lithium backup voltage present. One will be used to replace the 4464 in my 2465A scope the other will be used in my 2440 as soon I've also successfully backupped that SRAM. And because the square pins on the 16w08 to DIP adapter board are too thick for the standard IC sockets to be inserted into the scope SRAM position I also ordered 2 ZeroForce 28 pins 3M textool sockets that easily fit into the mainboard.
Update: The Tektronix 2440 SRAMS are HM62256 32KB type rams that require the special FM1808-70-PG ferro magnetic memory chips instead the FM16w08 (or the FM1608 DIP) that have 4 times more memory capacity compared to the original DS1230 32K chips often used in the 2440 memory oscilloscope. I was able to buy 2 FM1808s DIP on eBay for only US$5.89 (about 4,95 Euro). And they have a worry free retention time of 10 years without the need of any dangerous lithium backup battery. That also can leak in time! The above mentioned testclip with 28 pins socket cable can still be used after pin 26 is reattached to the testclip and its 100 ohm pull up is removed because it here is address line A13 instead of the CE pin it was on the 4464 SRAM.

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Many thanks for this fine post. Renewing a late model 2465B with bad power supply.

1/ Any tips on removal of the PSU for a novice? I have seen the teardown posts but it seems rather difficult.

2/ Some posts mention a 100 uF cap that must be exactly 100 uF, yet lytics are normally wide tolerance, your comment? Any list the exact caps you used?

3/ Besides recapping, are there any transistors or rectifiers prone to failure? Best part numbers to use?

Kind Regards,

Jon

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Thanks Justice and Albert. Sorry about the late reply but my shared internet connection at home often simply refuses to upload any of my comments. None of my 5 browsers do. So Jestine places them after I emailed them to him. And thank you Albert, I also do hope your Tek will servive for many more years to come!

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