maxtherabbit wrote on 2025-08-01, 13:29:

get a KSGER T12 for $75

hands down the best entry level iron

Yes, I can concur.

The key is that the heating element is in the tip, not part of the soldering iron. The soldering iron is just reallly a power supply and regulator for the tip.

All the magic happens in those T12 tips. They are fantastic.

I am sure the very most modern and most expensive soldering irons are even better, but the KSGER T12 with cheap ebay tips has gotten through every job I've needed it to.

My friend and I used a proper iron to clean up the socket and then reheat some of the joints, but it seems like the motherboard did not survive this butchery. No post, no beeps, complete silence, but the CPU does heat up. I think at this point a motherboard replacement is in order, with a replaceable battery this time...

multiplebaboons wrote on 2025-08-12, 04:46:

My friend and I used a proper iron to clean up the socket and then reheat some of the joints, but it seems like the motherboard did not survive this butchery. No post, no beeps, complete silence, but the CPU does heat up. I think at this point a motherboard replacement is in order, with a replaceable battery this time...

First, if you removed the processor from the socket, make sure it is firmly inserted. It happened multiple times to me that I didn't properly insert a processor into a ZIF socket (that's the type with the lever), resulting in a completely dead system.

At your troubleshooting experience, giving up on that board is likely the best choice to not waste any more time on it. On the other hand, the damage is most likely fixable by an electronics engineer experienced with PC motherboards in less than an hour. You only touched a very specific area of the board (where the DS12887 is located), so the location of the fault is quite well known. It's either a torn trace or a short (especially likely at the locations where your desoldering attempts damaged the coating called "solder mask"). While the signals at the DS12887 are not high speed signals, it is usual to have the DS12887, the BIOS and the keyboard controller on the same 8 bit data bus, which is routed through the DS12887 location. You see data traces (for the pins AD0..AD7) arriving on one side of the board and leaving on the other side. Removing a chip with an insufficiently strong soldering iron may easily cause pads or traces on the top side to be torn from the board, interrupting the lines. So I guess the no-boot issue you are facing is a damaged data line making the BIOS inaccessible. Perhaps you can use a continuity tester to verify that the 8 data lines arrive and leave the RTC location properly.

Nah, I didn't remove the CPU, only the RAM. One major issue is that I don't see very well in general and I think there are several shorts there. I ordered a headband magnifier just to take a look, but the bottom line is that I have never done this kind of stuff before and I should have listened to the few people here who suggested opening/drilling into the RTC chip without desoldering it... would still be butchery with a potentially damaged ISA slot (except mechanical damage), but overall those comments were on point.

I received a very generous offer from a member to mail it to them and get it fixed, but I am not even sure I am comfortable accepting this kind of effort -- even if the person is doing it for fun. Maybe if someone in town could do this, I'd at least buy them dinner.

As I said in my other thread, the board fully came back to life as soon as I got rid of a short. No issues that I was able to notice - and the RTC mod works. Highly educational on top of the sheer embarrassment, and thanks everyone for all the advice!