TDS 744A - Does it have a battery or NVRAM chip that needs to be replaced?

[AndersJ]

There have been lengthy discussions in this forum concerning
battery and/or NVRAM replacement in older Tektronix scopes.

Does anyone know if this is an issue for the TDS 744A?

[vaualbus]

All the nvram fail after 10 years so should bevxhanged. Luckly i think maxim have this nvram in free sample.

[AndersJ]

Please let me clarify my question.

Does anyone know if the TDS 744A uses:
* Discrete batteries for RAM content backup?
* RAM chips with built in batteries?
* Other batteries that need to be replaced?

In other words: Does the scope have batteries in any form?

[Andy Watson]

Service manual (page 1-12) says "Yes".

Data is maintained by small lithium-thionyl-chloride batteries internal to the memory ICs.

http://w140.com/tekwiki/wiki/TDS744

[ArcticGeek]

Yes, the TDS744A definitely depends on 2 batteries to hold configuration data and waveform data.

There is a DS1486 RTC part that has an internal battery - this holds the configuration data such as options and current state of the signal pass compensation.  There is also and NVRAM part that has an internal battery that holds the waveforms that you save to the reference waveforms.

These batteries are not replaceable though, they are internal to the encapsulated part.

Does that answer your question?

[AndersJ]

Yes, that is a clear and concise answer.
Thank you.

[nctnico]

Yes, that is a clear and concise answer.
Thank you.

From my own experience these batteries last much longer than their specified lifetime. Remember there is also a temperature range so if the scope has been sitting at room temperature the battery life will be much longer.

Secondly: several people have been able to mill the package open and replace the battery.