Nizo 801 Macro - faulty aperture??

[Mike Herdman]

Hi,

I bought my Nizo 801 Macro from a reputable website maybe around a year ago. I have not had a heaps of use out of it but have recently noticed that the aperture needle does not move, everything else is completely functional. The needle will not move with or without a cartridge and does not move with the aperture dial set to manual or auto, not even with the test button. It has had the complete light meter battery conversion to AA Batteries (No longer use the old light meter batteries).

I wish to do some troubleshooting myself but I am unsure where to start. Debris stopping the needle from moving? Galvanometer worn out? or maybe an issue with the battery conversion/conductivity?

Any help would be appreciated. Thanks.