In my personal quest of explaining to the world how badly written were the DB Daizenshuu guides, and how they completely misunderstood Toriyama's story at every single level, it's now time to demonstrate that they couldn't understand the Cell saga timelines either.
First, Daizenshuu's take on the subject:
So... Why is this explanation on the Cell saga impossible?
Cell only travels to the past because Trunks has already killed the androids, and Trunks only finds Guero's secret lab because Cell explains it to Piccolo!!!
In other words, the "Trunks uses the shutdown cotnroler to defeat #17" history is an incoherent paradox that could never happen.
Another absurdity is that there are 2 timelines with a future Cell in the past, with 2 cell games, which implies that Trunks made it's 2nd trip to the past in at least 2 timelines... which is absurd because with that amount of time-travels that changed the story there should be 1 or 2 extra TL at the very least.
4 is the correct number in my opinion, but not those 4 and surely not with that explanation that should at least need a coulple extra TL to make any sense.
The way they reason every timeline is absolutely laughable. They ignore the events in which Toriyama insinuated the changes happened and just tried to make coherence of the few details they paid attention to without thinking twice if what they said made any sense in itself.
Here's my take on the subject. In my case, the TLs are ordered chronologically (in other words, the first TL is the original one where Goku died and the one we know most it's the 3rd one -as 2 TLs were created prior to the one we saw-).
1st TL: No Cell -> No Trunks -> Goku & Z-Warriors beat Mecha & Cold in what's implied to be a hard fight -> Goku dies -> future androids kill nearly everyone -> Trunks goes to the past -> (2nd TL created here) Trunks fights Mecha & Cold with Goku & the other Z-Warriors -> Trunks goes back to the future and kills 17 and 18 -> (3rd TL created here) Cell kills future Trunks and travels to past
2nd TL: No Cell here -> Trunks appears and fights Mecha & Cold with Goku & the other Z-Warriors -> Trunks goes back to the future (to TL1) -> Unknown 2nd TL developments without any Cell having come from the future.
3rd TL: Cell arrives (3rd TL is created by Cell's arrival prior to Trunks' own arrival) -> Trunks (same Trunks from TL1) kills Mecha & Cold just before Goku arrives (TL4 implied to be created here) -> Trunks goes back to the future -> Trunks goes back to the past without killing -or having fought, it's not specified- 17 and 18 -> Cell games -> etc.
4th TL: Identical to TL1 until Trunks travels to the past for the first time -> Trunks comes back from TL3 -> Trunks goes to TL3 again without killing 17&18 -> Trunks comes from TL3 after the Cell games -> Trunks kills future 17 and 18 -> Trunks kills Cell
In Dragon Ball, a change made in the past creates a whole new reality that reflects that change, but the original timeline doesn't disappear.
Now, since the TL we know most about is the 3rd one (which is already a consequence of multiple changes in the past), we have to concentrate on the HINTS the manga gives us about what could've gone different if anything changed.
The most obvious changes in TL3 are Trunks's appearance (if Trunks acted just an instant later than he did, Goku would've appeared with instant transmission to fight Mecha and Cold) and Goku's illness.
The 1st TL has Goku fighting Mecha & Cold without Trunks in the scene.
We know that Goku's illness was aggravatted by the stress in his body (Vegeta observed this when Goku fought against #19), and there could only be one thing that could cause Goku more stress in his body than what he did in TL3: the Kaioh Ken.
In his fight against Cold Goku probably needed the KKx20 to defeat him as his untrained SSJ wouldn't be enough, which weakened his body even more which made his heart illness affect him much before than in TL3.
Everything else relevant for the explanation is just as the manga tells us (Goku dies, the androids appear and kill nearly everyone, no senzus to help, Gohan dies, Trunks goes back etc.).
The main difference between TL1 and TL4 is that in TL1 Trunks killed the androids just after coming back from TL2, while in TL4 he waited after he came back form TL3 for a second time.
Trunks travelled to the past to observe Goku and the other z-warriors fight, and learn something that would allow him to defeat the androids (or even ask Goku to come help in the future), and the only thing that could change between 1st TL Trunks and 4th TL Trunks in his first TimeTravel is the Mecha Freezer encounter.
So Trunks fought Mecha and Cold with Goku and the z-warriors in the 2nd TL, and in that fight he learnt something that was useful to him.
My bet, he learnt about the senzu beans: In Trunks' future, senzu beans disappeared years before Trunks even started to think about time travelling and it's very plausible that Trunks personally never saw one of them in action.
In the 3rd TL there's no fight against Mecha and Cold (both are killed instantly by Trunks) so no one used them and Trunks left after leaving the message to Goku, but in the 2nd TL that fight could've been as hard as the one that happened in the 1st TL, so it's only logical to think that the senzu beans were used, and upon seeing them, Trunks decied to bring some and fight the androids of TL1.
Another thing to remember: future androids were weaker than the present ones. Trunks was able to fight both of them without being clearly outmatched and probably lost to them because of their unlimited energy:
As to why future androids when different than the present ones, the most fitting explanation is that in the fight against Cold & Mecha the earth was damaged, affecting Guero's lab. That would explain why he didn't have time to create #19 and turn himself into a robot and he had to send #17 and #18 instead (who killed him before leaving the lab).
Now, for the differences between TL2 and TL3, we know that what provoqued them was the arrival of Cell and it had to be something very small, since Trunks decided to act in TL3 just at the moment Goku was going to teleport in front of Freezer. We don't know what Cell could've done in his Larva-state before burying itself on the ground to hibernate (probably feed himself) or maybe the sole presence of the TimeMachine in that TL triggered a very indirect change that made Trunks (or even Freezer & his father) act different in TL3 than they did in TL2.
Trunks kills Mecha & Cold before they could even put up a fight and so no senzus are needed, Trunks doesn't learn how useful they can be against the androids and he only leaves the message and goes back to the future, recharges his timeMachine and travels back to TL3 (and there the story continues as seen in the manga) creating TL4 in the process.
Finally, when Trunks comes back to what he thinks is TL1 (but in reality is already TL4, since in TL1 he fought against the androids) he kills them and Cell.
Of course, besides what's implied directly some of the gaps require a bit of imagination (mostly Cell's influence on TL3, but since the change between TL2 and TL3 is implied to be the smallest -it was just an instant what made Goku wait instead of teleport- anything is valid to explain it), but Daizenshuus explanation was made by someone that clearly hadn't understood the manga.
Regards!
First, Daizenshuu's take on the subject:
So... Why is this explanation on the Cell saga impossible?
Cell only travels to the past because Trunks has already killed the androids, and Trunks only finds Guero's secret lab because Cell explains it to Piccolo!!!
In other words, the "Trunks uses the shutdown cotnroler to defeat #17" history is an incoherent paradox that could never happen.
Another absurdity is that there are 2 timelines with a future Cell in the past, with 2 cell games, which implies that Trunks made it's 2nd trip to the past in at least 2 timelines... which is absurd because with that amount of time-travels that changed the story there should be 1 or 2 extra TL at the very least.
4 is the correct number in my opinion, but not those 4 and surely not with that explanation that should at least need a coulple extra TL to make any sense.
The way they reason every timeline is absolutely laughable. They ignore the events in which Toriyama insinuated the changes happened and just tried to make coherence of the few details they paid attention to without thinking twice if what they said made any sense in itself.
Here's my take on the subject. In my case, the TLs are ordered chronologically (in other words, the first TL is the original one where Goku died and the one we know most it's the 3rd one -as 2 TLs were created prior to the one we saw-).
1st TL: No Cell -> No Trunks -> Goku & Z-Warriors beat Mecha & Cold in what's implied to be a hard fight -> Goku dies -> future androids kill nearly everyone -> Trunks goes to the past -> (2nd TL created here) Trunks fights Mecha & Cold with Goku & the other Z-Warriors -> Trunks goes back to the future and kills 17 and 18 -> (3rd TL created here) Cell kills future Trunks and travels to past
2nd TL: No Cell here -> Trunks appears and fights Mecha & Cold with Goku & the other Z-Warriors -> Trunks goes back to the future (to TL1) -> Unknown 2nd TL developments without any Cell having come from the future.
3rd TL: Cell arrives (3rd TL is created by Cell's arrival prior to Trunks' own arrival) -> Trunks (same Trunks from TL1) kills Mecha & Cold just before Goku arrives (TL4 implied to be created here) -> Trunks goes back to the future -> Trunks goes back to the past without killing -or having fought, it's not specified- 17 and 18 -> Cell games -> etc.
4th TL: Identical to TL1 until Trunks travels to the past for the first time -> Trunks comes back from TL3 -> Trunks goes to TL3 again without killing 17&18 -> Trunks comes from TL3 after the Cell games -> Trunks kills future 17 and 18 -> Trunks kills Cell
In Dragon Ball, a change made in the past creates a whole new reality that reflects that change, but the original timeline doesn't disappear.
Now, since the TL we know most about is the 3rd one (which is already a consequence of multiple changes in the past), we have to concentrate on the HINTS the manga gives us about what could've gone different if anything changed.
The most obvious changes in TL3 are Trunks's appearance (if Trunks acted just an instant later than he did, Goku would've appeared with instant transmission to fight Mecha and Cold) and Goku's illness.
The 1st TL has Goku fighting Mecha & Cold without Trunks in the scene.
We know that Goku's illness was aggravatted by the stress in his body (Vegeta observed this when Goku fought against #19), and there could only be one thing that could cause Goku more stress in his body than what he did in TL3: the Kaioh Ken.
In his fight against Cold Goku probably needed the KKx20 to defeat him as his untrained SSJ wouldn't be enough, which weakened his body even more which made his heart illness affect him much before than in TL3.
Everything else relevant for the explanation is just as the manga tells us (Goku dies, the androids appear and kill nearly everyone, no senzus to help, Gohan dies, Trunks goes back etc.).
The main difference between TL1 and TL4 is that in TL1 Trunks killed the androids just after coming back from TL2, while in TL4 he waited after he came back form TL3 for a second time.
Trunks travelled to the past to observe Goku and the other z-warriors fight, and learn something that would allow him to defeat the androids (or even ask Goku to come help in the future), and the only thing that could change between 1st TL Trunks and 4th TL Trunks in his first TimeTravel is the Mecha Freezer encounter.
So Trunks fought Mecha and Cold with Goku and the z-warriors in the 2nd TL, and in that fight he learnt something that was useful to him.
My bet, he learnt about the senzu beans: In Trunks' future, senzu beans disappeared years before Trunks even started to think about time travelling and it's very plausible that Trunks personally never saw one of them in action.
In the 3rd TL there's no fight against Mecha and Cold (both are killed instantly by Trunks) so no one used them and Trunks left after leaving the message to Goku, but in the 2nd TL that fight could've been as hard as the one that happened in the 1st TL, so it's only logical to think that the senzu beans were used, and upon seeing them, Trunks decied to bring some and fight the androids of TL1.
Another thing to remember: future androids were weaker than the present ones. Trunks was able to fight both of them without being clearly outmatched and probably lost to them because of their unlimited energy:
Trunks: They weren't as outrageously strong as this... Even I could fight them fairly well...
As to why future androids when different than the present ones, the most fitting explanation is that in the fight against Cold & Mecha the earth was damaged, affecting Guero's lab. That would explain why he didn't have time to create #19 and turn himself into a robot and he had to send #17 and #18 instead (who killed him before leaving the lab).
Now, for the differences between TL2 and TL3, we know that what provoqued them was the arrival of Cell and it had to be something very small, since Trunks decided to act in TL3 just at the moment Goku was going to teleport in front of Freezer. We don't know what Cell could've done in his Larva-state before burying itself on the ground to hibernate (probably feed himself) or maybe the sole presence of the TimeMachine in that TL triggered a very indirect change that made Trunks (or even Freezer & his father) act different in TL3 than they did in TL2.
Trunks kills Mecha & Cold before they could even put up a fight and so no senzus are needed, Trunks doesn't learn how useful they can be against the androids and he only leaves the message and goes back to the future, recharges his timeMachine and travels back to TL3 (and there the story continues as seen in the manga) creating TL4 in the process.
Finally, when Trunks comes back to what he thinks is TL1 (but in reality is already TL4, since in TL1 he fought against the androids) he kills them and Cell.
Of course, besides what's implied directly some of the gaps require a bit of imagination (mostly Cell's influence on TL3, but since the change between TL2 and TL3 is implied to be the smallest -it was just an instant what made Goku wait instead of teleport- anything is valid to explain it), but Daizenshuus explanation was made by someone that clearly hadn't understood the manga.
Regards!