On Tue, Sep 17, 2019 at 01:40 PM, Albert Otten wrote:
But I think your suggested remedy is not working. The Z-axis blanking is
itself a result of internal signal. The only logical output of the Z-axis
circuit is the GSF signal which inhibits digitizing/storage of extreme Y
values. During retrace there must be some "inhibit" signal active which
prevents digitizing/storage during retrace.
It's won't be easy I think to pinpoint the cause. I spent a few minutes
reading the Theory of Operation and looking at some diagrams, but oh boy!
I'd expect what you mention, Albert, but I have to confess that one of my 7854's was exhibiting the exact same behaviour when I first got it and I'm sure slightly adjusting one of the pots on the Z-axis pcb did the trick... Of course, I don't remember exactly which one... Z-axis had to be adjusted anyway and the problem was gone at the same time.
It'll be interesting to hear from the OP.