I managed to acquire a Wallstreet Powerbook on eBay with a Sonnet 500MHz cpu upgrade. It came installed in an original Wallstreet and I decided to try it in the PDQ revision model. Everything I could find said that the sonnet cpu upgrades would work in either motherboard but when I test it the screen remains blank. I have tried several other cpu modules, from the original model with the same result 233MHz no cache, 250MHz, & 292MHz. With a 266MHZ daughter card from a PDQ model the computer starts as normal. I thought perhaps the problem had something to do with the different bus speeds, 83MHz for the 250 & 292, but both the 233MHz and the Sonnet 500Mhz modules have 66 Mhz bus like the PDQ module. After the computer completes startup I can hear the clicking of the OS9 interface when I press the trackpad button but no video. This suggests to me that everything other than the video is working OK. I have tried resetting the power manager and the PRAM with no change.
The reason for all this trouble is that I have observed the upgraded video in the PDQ model is noticeably superior running the OS X Jaguar user interface, such as when moving windows around on the screen.
Was there a sonnet upgrade that only works in the original Wallstreet?
Thanks for any suggestions