Tektronix TDS Oscilloscope NVRAM Replacement

[@miguelostermann9459]

interesting video, but no functional links, where can I get these PCBs?

[@nathanfulton]

Thanks for making this video, I just got a TDS754C and I'm preparing to do some preventative maintenance/upgrades on it!

[@Me-ld8bt]

Hi, I'm planning to do the same thing. Did the replacement NVRAM from the video work? Thanks!

[@t1d100]

I love your creative solutions/upgrades. Kudos.

[@wsalden9472]

Thanks for the video, it is really helpful. I have a question I hope you can answer. I have a new-to-me TDS 744A that I want to change out both DALLAS NVRAM chips. I understand the calibration data for the scope is saved in two serial EEPROMS. I read it is also 'mirrored' in one of the NVRAM chips and the scope uses this mirror copy when it starts. If I use a generic NVRAM image will this affect the performance of my scope? Can I copy my cal data from EEPROM to NVRAM or have I completely misunderstood the process? Thanks again for your great videos. They are very well done.

[@xConundrumx]

Are the board (aside from the ebay listings, shipping is a pain for this) designs available anywhere.

[@DarianCabot]

Love it 👍 nice PCB layout. Assuming the new batteries have an expiry date, might be worth labelling them for the next tinkerer :)

[@rogerioo8933]

Hi, Is it possible to post the gerber files and the BOM for each replacement? Thank you

[@jafinch78]

Excellent work! I've totally wondered about emulating and/or copying those Dallas chips. Wow! Thanks for sharing! Hope the poster regarding the newer firmware touches bases again when the USB/GPIB adapter arrives. That will be useful. I've wondered what novel custom upgrade hacks can be made with these besides those that are already shared online?

[@jafinch78]

I just noticed seller kellyjo_13 on ebay is offering exact functional replacements. Are you planning to sell or open source offer your PCB design version?

[@francoisleveille409]

What about those Cypress chips with automatic backup to flash ? I use CY14B101LA.

[@NearFarMedia]

They could work, but they are a 3.3V part is seems, they will need to have extra parts added to the circuit to translate to and from 5V supply voltage and logic levels.

[@francoisleveille409]

@@NearFarMedia To, yes, FROM ??? NO! 3.3V is both CMOS and TTL levels compatible. I do it using 74LVC245 which are 0.15$ each or 74CBTD3861 for bi-dir signals - 0.35$ each on LCSC or JLCPCB.

[@sneugler]

As you seem to have a lot of experience dealing with these TDS 600 and 700 series, what common faults should I check for first? I have a 744A that had the electrolytics on the mainboard replaced(no visible leakage before), and it refuses to boot with all of the lights staying on. No display out on the vga port, all power supply rails test great, and no difference when any of the board are disconnected. Any information/resources for fault finding would be greatly appreciated :)

[@NearFarMedia]

Hmm. First, double check that the PCB interconnect board on the right side of the scope along where the flex cables also are is the correct way up. One end is labelled 'acquisition' and should be oriented to plug into the acquisition board. An easy one to get wrong as it can be plugged in both ways. Make sure you didn't put the memory protection switch at the front right into unprotected mode, it should be switched so the rocker is tilted towards the rear of the scope. Also, what does the 7-segment display say when you turn it on? If it shows a number, it can direct you to where the fault could be. For example, a number 8 means that the NVRAM batteries are dead and they need replacement as shown in this video (8 usually means the one that isn't the Timekeeper is bad). Under normal operation, the 7-seg display should have two segments flashing back and forth in turn (think like the lights on a train crossing).

[@notsogreat123]

Are you going to make those boards available ? Or at least the gerber files ? Thanks

[@NearFarMedia]

It turns out the controller chips I used are a bit unreliable (some may be fakes possibly?) So I can't guarantee they work. There is a guy on ebay selling a similar design using a slightly different chip that works well though.

[@notsogreat123]

I'm aware of kellyjo if that's who you mean@@NearFarMedia

[@Igor-s3l]

Привіт!Які там стоять мікросхеми.Дякую?

[@bfx8185]

One question. If you did that effort why not design board with flash chips, which don't need any batteries.

[@robertfalls5876]

The RTC must have power on the DS1486 to function.

[@FLJ1954]

Why not just replace the Dallas NVRAM et load the firmware?

[@randycarter2001]

The life of these BB chips is extended by leaving the instrument on. As long as it is running the batteries don't have to provide power. But you still have the chemical degradation that occurs with time.

[@mariomionskowski6223]

Good idee..............................

[@TrunkMonkey42]

a replacement that does not need batteries? replace all these old junk battery form factors and standardize on 18650s?

[@NearFarMedia]

18650's have too much self discharge, the coin cells will last 10 years at least.

[@jamalabdul5529]

Do you have any scope for sale

[@NearFarMedia]

Eventually I will, but if you aren't in Japan, shipping will cost hundreds of dollars....

[@mickeyschroeder8537]

Ｐ?Ｏ?Ｏ?ｍ ?