The Soviet Army used every tank type they had left to invade Manchuria at the end of WW2, including BT's and old KV's. Was it only the KV-1S that was used, or were the older ones including the Models 1941 and 1942 as well?

It wouldn't be much of a stretch to think so.
Steven Zaloga's New Vanguard #17, KV-1 &2 Heavy Tanks 1941-45, has a colour plate of a KV-1S that was still in use during the Battle of Berlin.
Considering how poorly armed and armoured Japanese tanks were, I wouldn't be suprised if the Soviets decided to use any old "Eastern Front Campaigners" that they still had on hand to invade Manchuria.
Obsolete by 1945 standards, even a T-34/76 or KV-1 would be able to blow the s**t out of any tankettes or Type 95's and Type 97's they encountered.
Even if they had some of their newer Type 1's, 2's and 3's in Manchuria, the Japanese would still have had little chance against the T-34/85's and M4A2's that the Russians were also using.
Heaven help the Japanese tank crew that ever encountered an IS-2 Stalin.
Cheers

jjumbo

Ahahahah o god i can imagine it now.
what a walk over that would of been.
But can some one tell me did they even really invade manchuria?
Or where they just ready to invade just when the Japanese decided they had had enough?

Not sure what you're asking. The Soviets did indeed invade Manchuria with an Army Group ("Front" in Soviet terminology) and the Japanese Kwangtung Army they faced was the biggest force the Japanese had outside the home islands. This campaign doesn't get much attention, probably because it happened so close to the end of the war. Historians argue about what was more decisive in getting the Japanese to surrender - the two atomic bombs or the Soviet declaration of war. The Japanese did NOT want to be occupied by the Soviets!

Stalin had promised the US and Britain that the Soviet Union would enter the war against Japan three months after the end of the war in Europe, and they did so, rolling into Manchuria and northern Korea. The older light tanks like the BT-7 and T-26 had probably been there since before the war, but the other equipment had been brought in from Europe on the Trans-Siberian railway. There were still a few KV-1S tanks in service in 1945, but there don't seem to have been any of the older, heavier KV-1 variants, so I would doubt any would have participated in the Manchurian campaign. On the other hand, M4A2 Shermans, including some with HVSS and 76 mm gun, did participate.