Hi!

I have the exact same problem but on an early 1084, it uses same flyback as your monitor.

Did you find a solution for it?

JanOlausson wrote on 2023-03-18, 07:09:

Hi!

I have the exact same problem but on an early 1084, it uses same flyback as your monitor.

Did you find a solution for it?

No unfortunately , after some digging it turns out HR Diemen the company that makes replacement flybacks goofed the design.
Someone on youtube that I messaged had the same issue and tried it with a few different same model monitors but they all had the same issue with the HR 6489 replacement flybacks.

In the end I sold the monitor and another to a friend who wanted the tubes for a vector monitor project and used the proceeds from that to buy a CM8833 Mk2
which has the newer flyback and generally tends to be reliable.

Its a shame cause I prefer the looks of the older 1081 , 1084 series but unless you get a 1084S or newer there just aren't any functional replacement parts.

Thank you so much for the reply. I switched back to the old Flyback and everything works. The reasonI switched it to begin with was a high pitched noice.
It's really a shame that the replacement didn't work as this means these older monitors will die out.
I will also buy myself a CM8833 Mk2 like you did.

Ah, that high pitched noise. That’s something that don’t miss about my old 1084. It felt like it was giving me brain tumors after extended periods of use.

Those vertical waves from from flyback inductance not matching the original, and this causes some ringing between it and the yoke and other deflection components. This is normally supressed with a tuned network in the deflection circuit, mucking with it on your own isn't really straightforward.