I actually got one of these last year, exact same model, minus the dock. I posted about my adventures with it in this thread:

Toshiba Tecra 720CDT = Great DOS Gaming Laptop

I'm not a fan of laptops, but it's a really neat little system. I still have it though I haven't done much with it.

Well, shit:

the cells are standard 26650's but it's a moot point. When ripping the battery pack apart, i got a bit angry and ripped the flexible circuit board inside that did monitoring, load balancing etc. So much for just wanting to replace the cells and get the pack working.

I don't know who made that double sided tape, but that stuff was STRONG.

Careful application of heat sometimes help release the tape. I say careful because of the Li cells.

Wow, thanks for the warning pictures. I'd thought about doing this myself, now I know what to expect. If you had to tear into another one, how would you do it to avoid damage?

Ozzuneoj wrote:

Wow, thanks for the warning pictures. I'd thought about doing this myself, now I know what to expect. If you had to tear into another one, how would you do it to avoid damage?

gdjacobs wrote:

Careful application of heat sometimes help release the tape. I say careful because of the Li cells.

Seems legit.

well, 4 cells were leaking so it's not a terrible loss. I'm just disappointed in myself. I have no real interest in the machine. I just wanted to get it working nice for someone else, but its not really sellable without a battery pack and buying a new pack is $30. ( i looked on epay) THEN I would likely have to recondition that pack with new cells at $5 a pop, so another $30 on a system I wouldn't be able to sell for that much. I still have the shell, and its in good condition.

I'm like 50% confident I can kludge it back together.

I just put several layers of electrical tape over the battery contacts so I could leave the battery in place without it causing trouble. Mine came with the AC adapter though. It is tempting to get the battery rebuilt, but like you said, it isn't the most valuable machine ever... Plus it isn't that portable, so having it plugged in doesn't make much difference.

Ozzuneoj wrote:

Wow, thanks for the warning pictures. I'd thought about doing this myself, now I know what to expect. If you had to tear into another one, how would you do it to avoid damage?

looking deeper into it. Warm one side with a hair dryer. The side WITHOUT the 2 bottom terminals. Pry it apart. Clips will break. once the top is off, desolder the flexible connectors (4). Cut the cells apart. once apart remove them one by one until you find the one with the taped on temp sensor. I think it's one of the two middle cells Mine was on cell #4. The cells should just pop out then. You won't even need to mess with the circuit board. Take the time to check the diodes (between 2&3 and 4&5) and the temp fuse between 5&6. Cell #1 is the far left cell, away from the terminals. At least how I see it.

Is there some cheap way to get 26650 cells? Like, cheap new laptop batteries that have 6 26650s and are easy to get into? $30 is hard to swallow when there are plenty of new replacement laptop batteries out there that cost less than a third of that.

Is it possible to use 18650 batteries in place of 26650s without the thing trying to overcharge itself and catching on fire? It'd be way way cheaper to replace them with those and the modern technology inside newer 18650s would offset the lower capacity.

probably. but then you have to stuff the pack with something else. imho, id rather just use 26650 cells. less chance of cheap Chinese fakes.

luckybob wrote:

probably. but then you have to stuff the pack with something else. imho, id rather just use 26650 cells. less chance of cheap Chinese fakes.

I saw a video recently of someone using a fully charged cell to resurrect old 18650 cells that had discharged too much for their charger to work. I wonder if simply using another lithium cell with a sufficient charge could be used to bring back the cells in one of these old batteries... assuming it hasn't corroded or leaked yet.

I'm still looking around to see if any somewhat common batteries are still produced with 26650s that could be harvested as cheap replacements, but I haven't found anything.

at least with my cells, 4 of them show signs of leaking, so buying 6 is the only path forward.

95% chance I'm just going to toss the cells and sell the system as-is.

What a nice laptop you got there, let me know when you get around to selling it, I could surely use a laptop like that since I've been trying to get my hands on a DOS-compatible TFT laptop for years now.

Probably in the next week. I still need to fully test things like the pcmcia slots, the onboard scsi, etc. I'll probably format it back to windows 95. Just keep an eye on ebay.