seaken
Veteran Member
I have an old Tandy 1400FD that has dead batteries. This was the first computer I ever purchased for myself. I think I got it about 1988? It has been sitting in it's bag unused for several years. Both the main 4-cell battery pack and the RTC backup battery are dead. I was able to get some activity from the machine after keeping it plugged in overnight. The low battery LED comes on and the floppy drives get accessed with a seek (?) and the floppy lights come on and off. But there is no LCD display and no boot from floppy.
I figured this was going to require replacing both batteries. I have the Technical manual so I followed the instructions to remove the top, power supply, and floppies. That gave me access to the RTC backup battery. I expected to see a mess with a coroded battery, as I have so many times with some old motherboards with a Varta battery. But this motherboard is very clean and I see no signs of any corosion or battery leakage. The probelm I am having is that I don't quite know how to replace the backup battery. It seems to be soldered to the motherboard. I have clean access to the positive and negative leads. But I am not sure if I can just clip it off and then splice in a new battery.
Should I pull the motherboard and unsolder it? Or can I just clip it and solder on another battery at the legs that are left over after clipping it off? There does not seem to be any "External" backup battery terminals like I have found on some of my other motherboards. On those boards I just clip off the Varta battery and use the External header for a battery pack. But now it looks like I will have to be a little more technical. And I am not very good at soldering.
What is your recommendation? Can I clip? Or should I practice soldering on an old throw-away board first and then attempt to unsolder and solder in a new battery?
And can I still get a compatible battery for this thing?
Thanks,
Seaken
Here's some pics:
![IMG_20220807_153554629.jpg IMG_20220807_153554629.jpg](https://forum.vcfed.org/data/attachments/65/65993-f33f59521d7ac424239ed0e763710c1f.jpg)
![IMG_20220807_153545788.jpg IMG_20220807_153545788.jpg](https://forum.vcfed.org/data/attachments/65/65994-39d845c92af659dc0420a7fa8c82a6b9.jpg)
![IMG_20220807_154005026.jpg IMG_20220807_154005026.jpg](https://forum.vcfed.org/data/attachments/65/65995-07a7ab5f279e06486e91393947efec16.jpg)
I figured this was going to require replacing both batteries. I have the Technical manual so I followed the instructions to remove the top, power supply, and floppies. That gave me access to the RTC backup battery. I expected to see a mess with a coroded battery, as I have so many times with some old motherboards with a Varta battery. But this motherboard is very clean and I see no signs of any corosion or battery leakage. The probelm I am having is that I don't quite know how to replace the backup battery. It seems to be soldered to the motherboard. I have clean access to the positive and negative leads. But I am not sure if I can just clip it off and then splice in a new battery.
Should I pull the motherboard and unsolder it? Or can I just clip it and solder on another battery at the legs that are left over after clipping it off? There does not seem to be any "External" backup battery terminals like I have found on some of my other motherboards. On those boards I just clip off the Varta battery and use the External header for a battery pack. But now it looks like I will have to be a little more technical. And I am not very good at soldering.
What is your recommendation? Can I clip? Or should I practice soldering on an old throw-away board first and then attempt to unsolder and solder in a new battery?
And can I still get a compatible battery for this thing?
Thanks,
Seaken
Here's some pics:
![IMG_20220807_153554629.jpg IMG_20220807_153554629.jpg](https://forum.vcfed.org/data/attachments/65/65993-f33f59521d7ac424239ed0e763710c1f.jpg)
![IMG_20220807_153545788.jpg IMG_20220807_153545788.jpg](https://forum.vcfed.org/data/attachments/65/65994-39d845c92af659dc0420a7fa8c82a6b9.jpg)
![IMG_20220807_154005026.jpg IMG_20220807_154005026.jpg](https://forum.vcfed.org/data/attachments/65/65995-07a7ab5f279e06486e91393947efec16.jpg)