HP-41 Speed Upgrade

[MeindertKuipers]

Back in the good old time I was such a friend and did various upgrades, speed and module doubling, or building a module inside the HP41. It was a capacitor that was added, and a magnetic reed switch to switch back to the original speed (for card reader operations mainly).
The instructions are somewhere in the (archived) PPC Journals, so you need to look at the indexes.
Today I would not attempt this anymore and I only take an HP41 apart if I really need to do that because of the fragile screw posts. Simply too much risk. If you want a fast HP41 better invest in a DM41X or HP41CL.