External DVI Screens are flashing on/off on iMac 27" 2020 (iMac20,1) with USB-C to DVI Adapter(s)
Hello dear world out there!
I have a flickering Apple 23" Cinema Display and a same flickering EIZO CE240W display when connected to my newly bought iMac 27". Approximately: 2 seconds external display on, 5 seconds display off, 2 seconds on, etc…
In the system preferences it all looks nice. External display is visible & detected in a stable manner.
Right now i tested the following USB-C to DVI adapter and cable with the same issue:
Adapter:
- Lindy 43243 (USB-C --> DVI-female)
- StarTech CDP2DVI (USB-C --> DVI-female)
- StarTech DKT30CDVPD (USB-C --> Multiport with DVI-female)
Cable:
- StarTech CDP2DVIMM2MB (USB-C --> DVI-male) this one only tested on the EIZO
The same cable and adapters are working without any trouble on my MacBook Pro 13" 2018, with 4 Thunderbolts.
It seems to me if the iMac Graphic Card is somehow not compatible with the chipset of the adapter/cable. I found out that all of them uses the Parade - PS171 chipset, but i don't know if this chipset is the cause.
I will try another Adapter with a different chipset, hopefully i can solve the problem.
Any other suggestions or solutions from your side?
Any help and ideas would be highly appreciated. The testing to find the one cause is so time consuming ;-(