MacBook Pro (mid 2012) Catalina does not sleep when the lid is closed
I just bought a second hand mid 2012 MacBook Pro which is in extremely good condition for its age. It had Catalina installed but it seemed sluggish - windows would leave trails when moved - so before I migrated my stuff from my 2012 MBP 17 with High Sierra, I thought I'd see if a clean install of Catalina would pep the MBP 15 up a bit.
I installed Catalina on a new 2TB Crucial SSD and when I rebooted, I was happy to find that the MBP 15 performed as if it was new, albeit with nothing else installed. However, I discovered that when I closed the lid, the MBP did not sleep, the Apple logo remained lit and unlike my MBP 17, whose screen sleeps when the lid is about an inch open, the screen does not sleep.
I kept it next to me as I worked on my old MBP and kept glancing at the Apple logo and after about 15 minutes, the illumination switched off so there is no problem with it sleeping, per se, but it did not wake up when I opened the lid either.
Even though I didn't expect any results as the install was clean, I zapped the PRAM and the reset SMC and given that there is no other software installed, I don't know what else I can do. I'm pretty observant and I'm sure that I would have noticed that it did not sleep before the clean install and I have found a lot of discussions online which made recommendations which I have followed and which fixed the issue for some but did not fix it for many others, at least from what I read.
One other thing, the sleep/power light does not light up when it eventually went to sleep. I think I read in one of the posts (I read so many threads, I can't remember where it was now) that there is a link (apart from the obvious) between this operation light and the sleep function.
Whilst I am pretty sure that it did sleep when the lid was closed initially, it looks as if this might be a hardware problem but I am not as familiar with the internals of the MBP 15 as am with my old 17". If anybody has any suggestion, I'd be grateful.
MacBook Pro 15″, macOS 10.15