Mable
Member
I just a acquired a non working PP2 upright. Currently it is not booting and I have attached a photo of what is seen on screen (white spot is flash) and some pics of the boards. NOTE--The image seen was the same before AND after the items completed below.
What I have done so far.....
1.) Test point mod for both boards bypassing connectors for both 5 volts and ground. Adjusted voltage, tested on board to 5.15 for both boards
2.) Removed battery, cleaned battery alkali with Zep Toilet Bowl Cleaner, replaced parts in corrosion area, checked traces for damage/continuity and covered exposed traces with solder
3.) cleaned all edge connectors on video and cpu board
4.). removed all socketed chips on cpu board and cleaned legs of black corrosion with 600 grit sandpaper. checked sockets for corrosion though they all looked pretty clean....I have not removed and cleaned chips on video board
5.) Checked Sound microprocessor z80 for signs of life with a logic probe. Was getting clock signal and seemed to be functioning (ie pins were toggling)
6.). Switched the two z8002 microprocessors to see if that would cause any changes. It did not
I know the easiest thing would be to send it to someone but I don't want to give up yet if I don't have to.
I am open to suggestions on what next to look at next.
Is there a confirmed boot sequence published somewhere? I have been unable to find anything other than Ian briefly discussing it on one of his youtube videos.
I see why these things are a bitch. Thanks for any help
What I have done so far.....
1.) Test point mod for both boards bypassing connectors for both 5 volts and ground. Adjusted voltage, tested on board to 5.15 for both boards
2.) Removed battery, cleaned battery alkali with Zep Toilet Bowl Cleaner, replaced parts in corrosion area, checked traces for damage/continuity and covered exposed traces with solder
3.) cleaned all edge connectors on video and cpu board
4.). removed all socketed chips on cpu board and cleaned legs of black corrosion with 600 grit sandpaper. checked sockets for corrosion though they all looked pretty clean....I have not removed and cleaned chips on video board
5.) Checked Sound microprocessor z80 for signs of life with a logic probe. Was getting clock signal and seemed to be functioning (ie pins were toggling)
6.). Switched the two z8002 microprocessors to see if that would cause any changes. It did not
I know the easiest thing would be to send it to someone but I don't want to give up yet if I don't have to.
I am open to suggestions on what next to look at next.
Is there a confirmed boot sequence published somewhere? I have been unable to find anything other than Ian briefly discussing it on one of his youtube videos.
I see why these things are a bitch. Thanks for any help
