- The LaST Upgrade -

PART 12 - Falcon 030 DS12887A NVRAM RTC replacement

October 21, 2013 - Last updated March 17, 2023


The exxos low profile RTC module is a replacement for the failing Dallas RTC modules in the Falcon computers. It offers all the functionality of the original with the bonus of having a removable battery. The low profile version is smaller than previous gen exxos RTC modules and marginally smaller than the original Dallas RTC.

The module is fitted into the low profile socket and is the same height as the original Dallas module.

Fitting is simple. You need the low profile socket and the exxos low profile RTC module

You must use a sharp knife and cut the middle bar away from the socket. Do not use cutters as they will widen the socket as you cut often breaking the socket!

You must glue some card or preferably plastic on the underside of the metal shielding above the RTC module if refitting else if it touches the top of the battery, it will short it out!


Useful software links.

Xcontrol pack by exxos

Other RTC software NOTE not all software is compatible with the new module!


Headers do not look soldered properly ?
Some people have expressed concern about the headers not being soldered in correctly. This is by design. In the images above, you can see the solder "bumps" on top of the module are causing the battery holder not to lay flat to the PCB (production modules are not like that!) . As such, there is little solder on top of the headers. These are via holes and I assure you, there has been ample solder flowed "inside" the hole and was done under extreme magnification. Of course all modules are tested before dispatch.

Can I solder the module directly into the motherboard ?
I don't recommend it. It is technically possible but the pins will not protrude totally though the motherboard and the module may not lay flat. As a lot of people damage tracks unsoldering the old Dallas chip, it is beneficial to have a socket there.

My Falcon does not boot with the new module ?
Did your Falcon boot before ? Normally people have damaged tracks while un-soldering the old Dallas module, in which case your Falcon needs professional diagnostics and repair.
Secondly. If the floppy light is flashing extremely fast for a second, then stops for a second, then flashes fast again, then the Falcon is failing to talk to the RTC module. Again normally track damage, or battery not fitted. Also check the RTC software page on how to reset the RTC module on power up.

Can I use a different socket ?
I do not recommend it. Other sockets will be different dimensions and may not be good enough quality for a reliable contact. The sockets in the store are recommended. If you use a different socket, then you are on your own if your Falcon doesn't boot with it. It will also make the module a lot taller and the metal shielding probably won't fit back.

Time / Date settings are not saving ?
Check you are using the correct RTC software such as the Xcontrol pack by exxos which is tested working.
Check you do not have a flat battery (or it's shorting to the top shielding)
Check you do not have track damage to the RTC.

Time / date saving but not changing / advancing ?
Check you are using the correct RTC software such as the Xcontrol pack by exxos which is tested working. Reset the RTC module with software in the RTC software link. Remove the battery for 60 seconds and refit it and try again. Some RTC software disables the internal oscillator, causing time clock to advance.

Can you fit it for me ?
Short answer no. I get asked every couple of days to do such work and I just do not have time to run the store and do repairs / upgrades.

I screwed it up, can you fix it all for me ?
See the above question. Plus diagnostics and repair can take many hours to do. The cost of the work likely will total 100's if I take on the work. I suggest asking on the forum for people who may be able to help.

What battery do I need ?

Can't you supply the battery ?
No. Batteries need special handling and paperwork which just isn't worth the trouble for a 50p item. Plus some countries are refusing packages with batteries. So in order to save everyone headaches, I do not ship batteries.



My Falcon like many others has had a NVRAM fail for the past few years due to the internal battery going flat. In some cases it can prevent your Falcon from powering up, but more often than not, it simply looses the time and date. There is a boot floppy which I will upload later in this page which will reset the NVRAM in case that your falcon will not turn on due to bad NVRAM or corrupt settings.

First of all we need a replacement NVRAM. The old NV RAM in my falcon was a ST MK48T87B-24 TIMEKEEPER RAM. Which was to be replaced by a Dallas 887A NVRAM. The new Dallas chip is compatible but does have a few pins "missing" on the chip. These pins are N/C on the ST chip so it is of little importance. If you are unable to find the Dallas chip it can be found in my webstore. The chip is easy to change , though of course you need to have some basic soldering skills in order not to damage the Falcon PCB.

Above image shows the older ST NVRAM.

I recommend as the Falcon PCB has "Though VIA's" and is delicate to say the least, that a sharp pair of side cutters be used to cut the pins from the old NVRAM and then unsolder the pins left in the PCB.

Pin 12 ( far right pin on NVRAM in image) is the GND connection to the NVRAM chip, and was a pain to remove. There must be a huge copper area connected to the pin preventing the pin from unsoldering from the hole. I eventually got the pin removed. After using a high wattage soldering iron for some time.

I would suggest if this pin is hard to remove, then just cut half the pin off the NVRAM chip, and solder the NVRAM chip to the pin which is still in place on the PCB. This way the pin would not have to be removed and there is less risk of causing PCB damage.

With all the pins now removed, clean up the remaining solder from the pins and clean the PCB area, top and bottom, with IPA cleaner or similar. Use only a soft brush as to hard a brush may damage the solder pads.
Solder in the new Dallas NVRAM DS12887A , and do a final clean around the chip and make 100% sure everything is soldered correctly and nothing is shorting out. As pointed out before, the Dallas chip has a few "missing pins" but those pins are not used so its of little importance.

So time to boot up the Falcon. Initially the time and date all showed zeros. I changed the time in the normal Control Panel and double checked the settings were being saved. By default the date format was in USA mode, so it is important to change this to UK format otherwise the NVRAM will not save the settings correctly.

So now I have a happy NVRAM once again, see you all in another 10 years ;-)


These programs have been sent to me by Esa Sorsa which should allow editing settings of the NVRAM.