- The LaST Upgrade -

PART 12 - Falcon 030 NVRAM replacement

Chris Swinson - October 21, 2013

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, 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.

nvrcf030.zip
l_config.zip
rtc_chk.zip

 

 

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