![](https://www.eevblog.com/forum/testgear/archive-hp-54621d-mainboard-pics/?action=dlattach;attach=1561186;image)
![](https://www.eevblog.com/forum/testgear/archive-hp-54621d-mainboard-pics/?action=dlattach;attach=1561192;image)
![](https://www.eevblog.com/forum/testgear/archive-hp-54621d-mainboard-pics/?action=dlattach;attach=1561198;image)
These three pics were taken while I was investigating a replacement CDM-7SX191 monitor. I figured I'd add them here. If I have time, I may take more pics at different angles so a component list can be built.
So, while I'm working on this, I dismantle both the CDM-7SX191 and CDM-7SF191 monitors; after comparing the two mainboards side by side til my eyes watered, I couldn't find any material difference between the two. While the layout appear different between the CDM-7SX191 and CDM-7SF191 mainboards, the component list appears the same.
Voltages at the ribbon cable also appeared comparable aside from those I expected to be different due to the VGA analog video, but I'd literally need to draw out the entire schematic for both monitors to be sure.I didn't have time or energy for that tonight, so I took one for the team and just swapped the CRT neck board over and tried it.
![](https://www.eevblog.com/forum/testgear/archive-hp-54621d-mainboard-pics/?action=dlattach;attach=1561204;image)
Franken-monitor is no joy;
it is not possible to make a CDM-7SF191 serve as a CDM-7SX191 just by swapping the CRT neck PCB. ![Tongue :P](https://www.eevblog.com/forum/Smileys/default/xtongue.gif.pagespeed.ic.J5mTe0A2NA.png)
I'll update here as I have time.
mnem
![Tweak :-/O](https://www.eevblog.com/forum/Smileys/default/smiliey_cal.gif.pagespeed.ce.yYMcAvxBJk.gif)