Posts by jeffpc@mastodon.radio
(DIR) Post #AS0TWm89fx0CnNvI4u by jeffpc@mastodon.radio
2023-01-25T15:47:29Z
0 likes, 0 repeats
I have a #Ryobi #battery that refuses to charge. After many months of ignoring the problem and not using this battery, I decided to open it up and see what’s inside.There are 5 security screws, one of which is hidden by a plastic plug. The plug is made of hard plastic, so I managed to mangle it enough while trying to pry it out that I won’t bother reinstalling it when I’m done. #electronics
(DIR) Post #AS0TWmqT1CRp0oeg9A by jeffpc@mastodon.radio
2023-01-25T15:55:29Z
0 likes, 0 repeats
After removing the 5 screws, the shell can be removed. The inside is rather complex even though Ryobi is very much on the budget side of the power tool spectrum.On the bottom, there are 5 18650 Li-Ion cells connected in series. The board on top seems to regulate charging and prevents over-discharge.
(DIR) Post #AS0TWnauEXavKqNlWy by jeffpc@mastodon.radio
2023-01-25T16:01:50Z
0 likes, 0 repeats
I poked around with a multimeter, and I concluded that one of the cells died. It measures 0.2V. The other four are at 3.1-3.2V, which isn’t great but makes sense given that this battery has been sitting for a while.Removing a cell looks easy, but I haven’t done it since (1) I don’t have a replacement and (2) I need to befriend someone with a spot welder to reconnect the cell.I’ve heard somewhere that these cells are some kind of high current variant, which seems reasonable.
(DIR) Post #AS0TWoHRgNcdSmHjpw by jeffpc@mastodon.radio
2023-01-25T16:10:59Z
0 likes, 0 repeats
I could, in theory, solder the cells, but I’m not thrilled about putting that much heat into them. So, I’m shelving this project for now.Looking around the board for fun, I spotted two unpopulated connectors. The first looks very much like a debug UART. The second like I2C or SPI. I probed the UART header, but there was no data on it. (Which makes sense - you don’t want to use up the stored energy dumping out debug info while idle.)
(DIR) Post #AS0U9i4kgYdXVstevA by jeffpc@mastodon.radio
2023-01-25T16:19:27Z
0 likes, 0 repeats
@zleap Based on what I’ve read, it looks like the welds are easy enough to break. My concern is with connecting the new cell - it needs a quality connection which is easy to do with a soldering iron, but that transfers a lot of heat.I have a Hakko FX-888D and I can adjust the temp over a wide range, so that shouldn’t be a problem.
(DIR) Post #AXkv5e1OymOhhH32hs by jeffpc@mastodon.radio
2023-07-14T14:28:12Z
0 likes, 1 repeats
My first PCB is being manufactured! I really hope I didn't screw it up too badly :) #electronics
(DIR) Post #AkpGCUcoTV7nXGz9sG by jeffpc@mastodon.radio
2024-08-10T13:41:45Z
1 likes, 1 repeats
Weird. I have some #FreeBSD jails that are using VNET to get access to the LAN. At least as far as I can tell, some TCP packets sent to it exceed the MTU by quite a bit.Everything on the server is set up with a 1500 byte MTU but I see TCP packets with 2896 bytes in the packet trace. The jail doesn't ack them, and ~0.3 seconds later the first 1448 bytes get re-transmitted.After a few 1448-byte packets, the remote end tries another 2896 which causes a 0.3s hiccup,... yielding about 16kB/s 👎
(DIR) Post #AkpGCbzP5uM2NMbnYe by jeffpc@mastodon.radio
2024-08-10T13:47:43Z
0 likes, 0 repeats
The host got upgraded to 14.1 last night, but I occasionally saw this on 14.0. I just finally dug into it today :)This happens even with a freshly installed jail.
(DIR) Post #ArsDbMYyvLRSMb1040 by jeffpc@mastodon.radio
2025-03-08T21:31:19Z
0 likes, 0 repeats
@koakuma I’m going based on fuzzy memory of other architectures here. Some architectures include various flavor flags elsewhere in the ELF (maybe in notes?). This flavor is used by some ABIs for “this binary uses foo-type instructions” that the linker-loader can use. IIRC objdump can use those as well to tweak disassembly output. It’s been about 9 years since I thought about this, so I may be wrong.I’d compare *all* of the ELF contents.