can weak/dead backup batteries cause circuit problems?

[coppercone2]

If you are repairing a device, a portable analyzer for instance, which has multiple backup batteries which are dead, and the device is showing a memory error,

do you think that the backup batteries could have an effect on the circuit if its hard powered from mains causing a periodic reset?

Are these batteries typically installed to allow for normal operation if dead or are there designs that can bug out if they are not there? (3V lithiums, like motherboard backups).

I usually replaced them if I planned to work on gear but I never really tried to operate without one. They are a little pricey and hard to get so i'd like to know if it is at least a plausible problem

for 80's 90's designs.

so do you ever replace batteries before you find the other problems in such old equipment because you feel that it is causing or masking a problem making it necessary to replace?.

[SilverSolder]

I have a Wavetek signal generator here, from that period, which would periodically reset...  I wasted hours probing it to figure out what the problem was.  In the end, it turns out that a low back-up battery was the problem...  due to a not-so-cleverly designed circuit around it.  - so the answer is, Yes, it can be a problem, sometimes not intentional (i.e. the designer assumed the battery was there and working, and didn't bother designing for the case where it is missing!).

[coppercone2]

yea i got a wavetek 271 also that is temperamental that I need to deal with but this is a weird portable DSA. yea I should tend to that it reminds me of wavetek in how its built (sci atlanta labs or something)

im really juicing that thing for a few dollars, that wavetek just became a priority fix. I wonder if the other wavetek big rackmount has em too.. .

[coppercone2]

any idea how to replace a renatas 250-00 power module?
I know nothing about these in circuit backups or designing them honestly. Is it just a coin cell with a different reliability? or does it have some kinda good ESR or other behavior making premium necessary?

does anyone have a old app note that tells you how to design these circuits so I know what these people are thinking when they do this?