How many chips are on your SIMMs?

I have tried 1 MB SIMMs with 2 Chips and with 8 Chips.

I installed 2 identical of them on the card in banks 1 + 2.

There's a pretty good chance the battery in that Dallas module is dead and with lack of settings that can be retained it may malfunction like that.

So I "eliminated" the Dallas Eliminator 😉

When comparing to the datasheet the Pins 1+24 are missing on the Dallas. I assume these are bent to the top and the battery is connected there? Does it makes sense to start at this location to look for the battery?
Unfortunately there is not much to find about DS1292 or fixing its battery...

Yeah, battery is most probably right there and I would start grinding it open at that end, it shouldn't take a lot of effort to get access to the battery terminals. You will probably need to grind enough to identify the postive or negative terminal to be sure things are correct since reverse connection often causes damage.

Sorry but do not think you will find a battery off pins 1 and 24. I DL'd the 160Mb Dallas book off Archive org and it says those pins are Ground and only present on the DS1293. There is a battery in there but darn if I can figure figure out how to get to it by pins (maybe cut the whole top cover off ?). Attached the scans in case someone else wants to take a look (sorry the orig scan were small)
Good luck Predator99 !

edit: fixed bad grammar due to having a few beers ;p

I'm confused by your picture; The DS1292 was U6 which is now empty, and you've put something new in U1 and circled it when talking about the pincount of the DS1292?

Thanks for your replies!

I already attached the datasheet under my initial post, thanks for searching again anyway 😉 Its confusing as in the datasheet the DS1292 has 24 pins. But my specimen has only 22 pins.
I understand both the 1292 and the 1293 have 24 pins according to the datasheet.

Picture: Look again 😉 The IC with the circle is the desoldered DS1292 with pins showing up 😁

Ah it's a dead bug. I wondered why the legs looked strange.

Because there's a plastic case epoxy'd around the chip.

I have to admit not the nicest work I did here 🙁

I was right the baterry is connected to Pins 1+24. But there was no Charge left at all so I had to dig further to see where is + and -.

The battery is not labeled but I assume its (+) on the top and 3V....

I really like these Dallas Chips....

Good cut job ! On all the Dallas I frankensteined, the battery - is also grounded and they are 3v. Using a good DVM measure Ohms from pin 12 (chip GND) to the battery and you should be able to verify which part of the batt is the - side.

Wait...chip ground is (-) ?

I assumed the top side of the battery is (+). But the top side of the battery is connected to Pin 1. And there is a connection between Pin 1 and Pin 12 (GND).

That mean the top side of the Battery is the (-) side..?!

I also verified Pin 12 (GND) assigment is correct as the corresponding mounting hole is connected to ISA-GND (green).

Battery top connects to Pin 1:

Predator99 wrote on 2020-03-08, 15:22:

Wait...chip ground is (-) ?
I assumed the top side of the battery is (+). But the top side of the battery is connected to Pin 1. And there is a connection between Pin 1 and Pin 12 (GND).

That mean the top side of the Battery is the (-) side..?!

Yes ! Just like the DS1287, the batt - is on top and does go to ground, like in this picture

OK THANKS..! You prevented me from making a big mistake...it was totally clear for me that (+) is on the top like it is on a CR2032.

You could put a small signal diode in series with the new batteries + as a first test. I did with a DS1587 (which are impossible to find), test worked and removed the diode, now has battery wired direct to it.

Hmm, dont have a diode...

This is going to be my test setup - any objections? 😉

Thanks again!

Looks good to me ! I used the diode as a micro 50mA fuse but a 100 ohm resistor would limit the current too. Think I was being a bit over careful and over thinking things when I did that 😁