Replacing the RAM in the Sega Teradrive
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- Опубликовано: 29 янв 2021
- After the Teradrive began rebooting itself while sitting idle, or rebooting itself while I was trying to work on it, I decided it might be time for the machine's first repair since I've owned it.
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Beautiful machine!
is the system soldered like the pioneer laseractive cld-a100?
is it easy to repair when something not working?
In the video, you say that the module you removed and the one you replaced it with are both 2MB. It's shown that you have two modules installed, but you said that when you removed the one "bad" module, you were left with only .5MB. The unit comes with .5MB soldered to the main board, so, with a single SIMM installed, the minimum RAM you should have available is 1MB if the SIMM is functional (assuming the on-board RAM is functional as well).
In any case, I'm curious as to whether the module really is 2MB, because the maximum amount of RAM an unmodified Teradrive can use is 2.5MB (1mb+1mb+512kb) due to some of the pins for the SIMM slots not being wired to the MMC. It's possible to (physically) modify it to accept up to 8.5MB (4mb+4mb+512kb) which is something I want to do with my Model 3. In preparation, I bought some 4MB SIMMs and I've already tested them out in the system. I was hoping that I could install them now even though I would still only be able to access 1MB on each module, but the system seems to become very unstable, and I've been unsure if it was because of the capacity or if there's some other property of those particular modules that isn't compatible with the Teradrive. My understanding has led me to believe that I could use a higher capacity module with greater access speed to benefit from the access speed even without being able to access the full capacity. It must also be possible to use modules with greater access speed than the stock modules because comments made on a video by someone who has made the 8.5MB modification specifies that while the default wait state is set to 1, it's possible to set it to 0 without repercussion. Since I've found this to be untrue with stock modules, I can only guess that his 4MB modules have faster access speed.
Can you provide the spec for the 2MB module(s) you appear to be using successfully without the 8.5MB mod?
Here is a link to the video demonstrating the mod I mentioned:
ruclips.net/video/9OKX9Apyub0/видео.html
Interesting.. the 512kb on board wasn’t something I was really aware of - I’ll need to pop the cover back off and take both simms out to see what happens but I could have sworn it was a 2MB and a .5MB module that was giving me 2.5. I know the simm I put in it was 2MB
So are you screwed if the HDD dies?
I have the exact same thing on my model 2 !
The rebooting? It came back after I made this video. Try pushing the PC/MD selector switch **hard** (not hard enough to break it) to the PC side. I found out that barely moving toward the MD (left) side would cause a reboot because it was essentially kind of stuck between modes. Anytime the rebooting starts, I push that switch to the PC side a little harder and it stops.
@@ukozi ahh cool i'll also try that.
Have you tried installing an xt-ide board? Or a cpu ugrade?
@@CousinHubertRetrogaming I now use an XT-IDE with a riser board that has an additional ISA slot on it so I can still use the expansion port around back. Have not done anything with CPU upgrades.
@@ukozi oh cool! Can you copy paste a link to the riser you are using? I searched everywhere to no avail ... also what kind of 3d game were you able to run kind of on the teradrive? I found chuck yeager's air combat was barely playable with minimum details. Lucasfilm point and click games were ok!
I have a model 3 that does the same thing and can confirm ukozi's response - this seems to be related to the MD/PC switch. When the resets happen, you do indeed have to force it *hard* to the PC side to get it to stop. Leave the TD on and force the switch to PC until it starts back up in PC mode. Give it a little more force and when it seems to be stable, release *very* slowly to avoid the switch pulling back to the left. It might take a few attempts before it fully stabilizes, and moving the unit around can cause the problem to reappear. Flipping the switch to MD will definitely require you to perform this process again when you want to switch back to PC.
I eventually want to see if this is something that can be fixed by physical modification.
expansion port for a excluisve mega cd model for this? Lol
Put android on it