CCR1016 / Temperature sensor defect?

Hardware MikroTik hardware general
1

We have two (old) Mikrotik CCR1016-12Gs in the same rack, one above the other. One has been showing an increased CPU and motherboard temperature of >85°/70° for a few days. The fan spins at almost 8000 rpm. But CPU is almost at <10%, memory <500Mbit from 2G, firewall and interfaces are hardly loaded.
We have now unscrewed the router. It didn’t feel particularly hot. The air coming out the back is also just warm, not hot. The second router has a temperature of 52°/40°.
Another difference is that the router with the supposedly high CPU temperature has about 21 volts, the other one has about 24V
Is it possible that the temperature sensor in one CCR is defective? What can we do?

CCR1- high temperature:

#  NAME             VALUE  TYPE
0  voltage          20.7   V   
1  temperature      73     C   
2  cpu-temperature  85     C   
3  current          0.7    A   
4  fan1-speed       7827   RPM 
5  fan2-speed       0      RPM

CCR2 - OK

#  NAME             VALUE  TYPE
0  voltage          23.7   V   
1  temperature      42     C   
2  cpu-temperature  52     C   
3  current          0.9    A   
4  fan1-speed       3494   RPM 
5  fan2-speed       0      RPM
2

21V sounds like faulty PSU or significant fault on board overloading PSU. Both would cause increased consumption and heating. Better get it repaired until something blows out. Since fans spin up to compensate it wont feel hot to touch until it’s catastrophic.

3

There have been previous reports on this forum about CCRs with similar symptoms. All have been resolved by replacing capacitors in PSU and/or main board, which showed signs of failing (bulged ends). When doing it, make sure that replacement capacitors match capacity of original ones (too big difference in either direction will cause problems) and match or exceed the rest of ratings (voltage, temperature).