Decided to record some thermal videos of my A1 bed and the bed cable (under recall) to see what’s going on. Interesting note that the bed had some wide variations (51C - 57C avg but as high as 67). Also noted the cable appears to be fine (~17C). …and yes, I am aware of the recall. 
Recorded using an InfiRay P2 Pro
Neat, considering the temperature shifts dont seem to align with the heating coil that much i’d guess youre seeing a big shift from the parts fan cooling off the top surface (can be tested by just printing somewhere else on the bed and see if the cooler zone follow suit. and i’m not sure how the pebbled plate affects thermal imaging either…
I assume the slight hot spot on the cable coming out of the bed is due to emissions from the bed and it being “out of focus”.
That’s a good point… I may do another video where I just turn on bed heating only (no print job/fan) and see if those inconsistencies change. Not sure what hot spot you are referring to re the cable?
i know the cable runs a bit further under the bed so it picking up residual heat from the heating is no surprise either.
I measured the temperature of the table set to 80 degrees and the temperature deviations were significant, 73-90. Now I know why the prints on one side of the table were able to peel off. Only the temperature around the center of the table was correct
Here’s another video set to heat @ 50C without printing to remove influencing factors such as tool fan etc. Recording purposely cut to start at 1 min mark. To note that the screen/software indicated it was done (at the start of this video) heating to 50C even though this suggests otherwise (likely because of the thermistor location).
Note: not trying to bash BL here. Just wanted to record process to help inform potential future issues. I have had a few situations where small PLA prints broke away from the bed while printing.
Ya people often suggest “pre-heating” table for 10 minutes before printing to give it time for temperature to diffuse more uniformly.
I wonder how it’s looks, if you test again after 6-8 minutes
Yeah. It gets better given the A1 goes through some routines before printing which are usually 5 mins or so, so temps would be more uniform (like in the first video I posted with it printing). I’m not concerned, just made for good justification for the expense of the InfiRay camera I told myself I needed to buy! 
Question, are you running it on 110V or 240V? asking because the coil doesnt seem to be outputting that much heat in the central part of the loop, indicating that its resistance might be a bit to high for the current to reach the center of it (albeit i’m not entirely sure of the inner works of heating coils). Could also be an effect of poor themistor positioning as well tho.
What’s your emissivity set to?
110V… Also to note, the PEI plate was in place.
The cable won’t show anything until the insulation wears away from flexing and it shorts. Then it will be very bright.
Not really. As soon as a few strands inside the cable break current handling capability of that section lower. As a result that sexual warm up and why I doubt he has is emissivity set right he’ll still be able to see a temperature difference in that part of the cable
Yes, I forgot about that. I need to get one of those gadgets. Excellent point.
Naughty naughty cables - there might even be inappropriate see-through insulation involved! 
There is a material called CeraTex that I’ve been looking at adding into the heat coil area, It should be able to hold the heat in better in those void areas. It’s electrically non conductive and very thin. There is a lot of areas underneath that are not insulated so you have heat leakage from the bottom. I’ve used different materials on my Ender 3’s and heat bed temps are very stable now.
They sell it on Amazon CeraTex 3170 Ceramic Fiber Paper