It is possible to "upgrade" a 6632B System DC Power Supply to a 66332A Dynamic Measurement DC Source.
WARNING: By following this process, the unit will lose its calibration and has to be recalibrated!
Their hardware is identical, but the 66332A has an enhanced feature set for measuring transients and saving up to 4096 samples. The digital board, which you can see in this previous post, has 3 programmable devices on it, the main firmware ROM, a Xilinx PROM and a PAL.
But fortunately the only difference seems to be the main firmware in the U205 ROM which is a 2Mbit OTP-EPROM, in my case an ST M27C202-70K6. I have built a small PLCC44 to DIP40 adapter board to use it with my TL866II programmer, because the supplied adapter is not pin-compatible.
So I was able to dump the 6632B A01.04 Firmware and burned the 66332A A01.03 firmware from this eevblog post to an old (1989!) AMD AM27C2048-200.
After turning it on, it showed error 1, which is related to the changed checksum of the ROM. This can be resolved by entering the "secret" menu pressing the 0 and 9 key at the same time and selecting "EEINIT 66332".
You can find the complete calibration and performance verification procedure in the service manual. After calibration you have a full working 66332A.
If I have some time, I will do some in-depth testing and post the results here.
Links
Service Manual: keysight.com