I pulled out of storage this weekend my old Pentium 166MX PC and unsurprisingly the real time clock had died. Thankfully the RTC is socketed! The fitted RTC is VT82887. Looking at datasheets I believe a DS12887A is a suitable replacement. I've also seen pictures on the internet with ODIN 12c887a. Can someone confirm a DS12887A is suitable?
BTW, curiously the motherboard (Soyo 5VA) has marked on the motherboard, next to the RTC chip, a space for a coin cell holder. I tried to see is the pads for the holder are connected to the RTC chip, but no they are not.
RTC VT82887 Replacement
RTC VT82887 Replacement
Richard B
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Acorn Electrons issue 4 and 6, MRB, Plus 1 x2, Plus 3, AP6 x2, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi Co-processor, GoSDC MBE.
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Re: RTC VT82887 Replacement
The other option you might like to consider - given that new RTCs in that style are quite expensive and will die again after a few years - is drilling into your current RTC and attaching a replaceable battery to it. It looks like someone's done that in this photo of the board you've got. Worth a try if you're planning on replacing it anyway...
Re: RTC VT82887 Replacement
I have seen it, and others doing the same thing with their RTCs. Weighing up the options. Thought I'd get a replacement just in case I messed up doing this mod. There are also options like this available https://www.ebay.com/itm/304462338410, but the price with shipping from the USA (to Greece) makes it more expensive than buying a replacement.atsampson wrote: ↑Mon Dec 18, 2023 5:26 pm The other option you might like to consider - given that new RTCs in that style are quite expensive and will die again after a few years - is drilling into your current RTC and attaching a replaceable battery to it. It looks like someone's done that in this photo of the board you've got. Worth a try if you're planning on replacing it anyway...
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1 x2, Plus 3, AP6 x2, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi Co-processor, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi Co-processor and Gotek.
Acorn Electrons issue 4 and 6, MRB, Plus 1 x2, Plus 3, AP6 x2, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi Co-processor, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi Co-processor and Gotek.
Re: RTC VT82887 Replacement
Bought a nwX287 https://github.com/necroware/nwX287 off eBay (from Spain, 18 Euros including postage), and it works!
It appears that DS12887a cannot replace a VIA VT82887. It always gives you a CMOS checksum error in my Soyo SY-5VA motherboard.
It appears that DS12887a cannot replace a VIA VT82887. It always gives you a CMOS checksum error in my Soyo SY-5VA motherboard.
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1 x2, Plus 3, AP6 x2, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi Co-processor, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi Co-processor and Gotek.
Acorn Electrons issue 4 and 6, MRB, Plus 1 x2, Plus 3, AP6 x2, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi Co-processor, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi Co-processor and Gotek.