Re: Differences between 8501R1 and 8501R4

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Thu, 5 Dec 2019 12:46:51 +0100 Message-ID: <a1ed2f0a-a160-af60-d6ff-af4788bae53d_at_laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 12/5/19 12:29 PM, fhw72 wrote:
> The R4 is said to be much more reliable compared to the R1.
> However I cannot judge as my stock consists of R4 only and I never
> had a defective R1 myself.

The reason could also be the year they were made in. In 1984, HMOS-II 
was pretty new, at least at MOS and the 8501 and 8360 were about the 
start of doing HMOS-II at MOS. In 1986 they probably had the process 
figured out and stable so the 8501 made then do hold up better. After 
all, the earliest instances of the 8500 appearing in a C64 were in 1985 
and those were not known for causing problems.

In a related note... The 8500 is known in R3 and R4.

  Gerrit