This old Beauty was sent for repair and refurbish by retro protect, suffering from a high bank RAM Fault.
The system was completely ...stripped and all plastics soaked in disinfectant and then thoroughly washed with warm soapy water removing most of the yellowing (nicotine ?).
The Ram fault was down to a missing CAS signal to the upper bank DRAMS courtesy of a 74LS257 which was replaced, sadly a good few RAMS had died.
I removed all the 8 hi bank RAMS, cleaned the board and fitted low profile DIL sockets replacing the surviving RAMS and supplying new 4164 chips as required.
Using a Commodore C128 Diagnostic cartridge all RAM now tests good.
Note - the Chips highlighted Bad are simply because the Test Looms have not been fitted to the system thus loopback tests fail.
All PCB's were thoroughly cleaned as well as the 1571 Mechanics.
System rebuilt as shown in the pictures.
Serviced the 1571 Drive and checked the Alignment was true, heads cleaned.
And another beauty lives to play another day
The system was completely ...stripped and all plastics soaked in disinfectant and then thoroughly washed with warm soapy water removing most of the yellowing (nicotine ?).
The Ram fault was down to a missing CAS signal to the upper bank DRAMS courtesy of a 74LS257 which was replaced, sadly a good few RAMS had died.
I removed all the 8 hi bank RAMS, cleaned the board and fitted low profile DIL sockets replacing the surviving RAMS and supplying new 4164 chips as required.
Using a Commodore C128 Diagnostic cartridge all RAM now tests good.
Note - the Chips highlighted Bad are simply because the Test Looms have not been fitted to the system thus loopback tests fail.
All PCB's were thoroughly cleaned as well as the 1571 Mechanics.
System rebuilt as shown in the pictures.
Serviced the 1571 Drive and checked the Alignment was true, heads cleaned.
And another beauty lives to play another day
