I think taking the 1975 approach with a JW is...weak. Was it wrong (and false prophetic) of them? Absolutely. But technically the didn't actually say "Armageddon will come by 1975". The elluded to it. The did everything BUT say it. But the fact remains, they didn't say it WOULD happen.
In front of me is the book God's Eternal Purpose Now Triumphing for Man's Good (1974 WTB&TS) In the front of this book my wife has written the date August 1974 and the assembly she recieved the book at I presume. Inside there are several other dates relating to when it was studied at the meeting I assume. Starting in December 1974 and the last date is May 1975.
On page 131 in paragraph 5 it states,
"The first half or 'evening' period of God's seventh creative 'day' was now closing, 3,500 years from the creation of Adam and Eve. The morning of this creative 'day' was due to begin at 526 B.C.E."
This was under the heading, "Morning of the seventh Creative day begins 526 B.C.E."
Earlier in the book on Page 51 there is a subheading "Evening of the Seventh Creative Day begins 4026 B.C.E."
From these statements I would conclude that the seventh creative day was 7000 years in length and started in 4026 BCE. Maybe I reading it wrong but I don't think so as this is what I understood at the time that we believed the creative days to be 7000 years long.
On Page 53 the book says "At the beginning of this 'seventh day' almost six thousand years ago God 'proceeded to bless the seventh day and make it sacred.'"
As it says it was almost 6000 years into the seventh creative day. Which I believe would be exactly 6000 years in in October of 1975.
The last chapter of the book is "Making the Seventh Creative 'Day' Sacred" page 187.
on page 189 talking about Satan the Devil it reads,
"For six thousand years he and his seed have been allowed to continue their effort to make it seem to be a cursed day unsacred... During the thousand years that the Great Serpent and his demon seed are abyssed, Jehovah will reverse all the wickedness."
This thousand years of the Devil being abyssed was yet to come but before the end of the 7000 year seventh creative day.
On the following Page 190 it says,
"...God's seventh creative day will end up blessed, sacred, sanctified. Jehovah having blessed that day six thousand years ago..."
On page 186 it says "With all his earthly seed destroyed at Har-Magedon," it then asks the question "Are the original serpent and his invisible demonic seed to be left on the loose in the vicinity of our earth down to which they have been ousted from heaven? No!"
"By removing the Serpent and his demons from the nieghborhood of the earth and hurling them into the abyss and sealing them up there, bound as with chains for the next thousand years. Revelation 20:1-3 pictures this, not as a part of the war at Har-magedon, but as a follow up of that war."
So from this book released in 1974 and I believe studied in 1975 it showed that 4026 was the start of the 7th creative day it would end up sacred and blessed with the devil abyssed after Armageddon for the last one thousand years of the 7th creative day.
The first 6000 years of the 7th creative day would end in 1975 the last one thousand years being the abyssing of the Devil after Armagedon during the thousand year reign of Christ.
Unless I've misunderstood something I think they were teaching that Har-magedon would occur in 1975