New findings and solutions for the R5 overheating situationand and an easy solution that works and unveils a bit about the internal construction of the R5. First we have 2 major sources of heat generation, the processor chip, where we believe an FPGA is used and the CFexpress card. When you record without the CFexpress card using an external recorder, then one source of heat generation is eliminated. Canon cannot know the exact temperature of the CFexpress card. To my knowledge the cards do not have an inbuilt temp sensor and Cannon does not sense the temperature at the casing. But, Canon must make sure that they do not overheat and damage the CFexpress cards. This is one reason I believe that they estimate the temperature by a SW algorithm. The second heat source, the processor cannot be eliminated, but may be the heat can be better disposed, for example through the metal base plate. I did this with many products I developed.
Now the real problem Canon created is the relax time after shutdown. This is also SW algorithm defined and not related to measured temperature.
Now you need to cool the camera and the card. Later we need to tell the SW not to remember the previous recording to avoid the length cool down time. Here are my findings:
You can create easy air flow through the camera. There are 3 openings that can be used:
1. The sensor compartment after removing the lens.
2. The card compartment which allows open air flow inside the electronics compartment.
3. The battery compartment, that is also not air tight and allows air flow to the electronics compartment.
All three compartments allow air flow to each other. This allows to cool the interior of the R5 very efficiently. I just need to open the card or battery slot and preferably remove the lens with the shutter open. I blew through the card slot and could feel the hot air coming out of the lens opening. After a very short time the air is not recognizable hot anymore. As long as the temperature difference between the components and the air is big, the cooling effect is high.
Solution:
Now, the real trick based on the sticky tape approach from J.Marcus. The mechanism is the following: When you switch the camera off, you only create a signal that the camera uses to stop operation. We call this an interrupt, which triggers a shutdown routine in the firmware. This routine is executed by the processor, which needs at that time still power. The shutdown routine saves all relevant configuration data at that time into a C-MOS ram chip, probably combined with the real time clock chip. A part of this savings is the overheat status calculated based on the camera use/recording time. The the camera goes to sleep mode.
When you switch it on, or close the card or battery door the CPU is woken up again. You see this when the red LED is blinking. If you use the power switch the camera reloads the values stored before.
But, if you remove power abrupt, then the shutdown routine cannot be executed. The saving of the status data does not happen, instead the data from the last regular shutdown are still in the C-MOS ram saved.
How can you remove power abrupt?
Remove the battery without deactivating the door closed switch. Some manipulation required.
Open the battery compartment is you use a grip. There is also a switch, but it is very easy to manipulate. A 1x1 mm paper piece of a business card does the job.
Open the cable connection to an external dummy battery (wall power or large external battery pack). You don't need to hack the switch if you use this, but you need an external power source. You can use this with or without grip.
Important is that you remove the power that way before the overheating appears. Cannon seems to store a timestamp in combination with an overheating bit and a thermal shutdown bit.
What I do for recording. I configure the camera first, the switch it off to save my setup, switch it on again and start recording.
Wait just before the overheating warning shows up and remove power abrupt before the overheat warning finally shows up. You need to control the time by yourself.
Cool it or not, restore your power source and you can continue recording.
See the photos how easy it is and how small the paper is when I use it with a grip.
This little effort allows you and me to use the R5 as intended. Tell Canon if you see them.
66
2 comments
Like
Comment