// 2024-09-18 // by Elder0010
This machine belonged to the Raoul’s loot. The Commodore 710 belongs to the CBM-II family, and is definitely a strange computer. It is based upon the MOS 6509 cpu, which is a MOS 6502 with bankswitching features. It can address up to 1MB (!!) RAM. The whole CBM-II set of computers has been retired from market soon after their debut, and the software ecosystem has been somewhat mantained by the user groups in the past, and by the estimators nowadays. CBM-IIs are the only Commodore 8-bit machines with an RS-232 port instead of the standard user port. Luckily, Raoul didn’t lose the keyboard - it’s very common to find CBM-II of the 700 series without one. I wonder how it could be possible to lose a 2kg HUGE keyboard with this frequency, though.
Repairing this computer has been quite a challenge! At first I had to take it apart for visual inspection and cleaning. There was one broken screw in the monitor back cover, but I managed to remove it. The plastics of the early PET/CBM II are undestructible, it’s quite common to find one in pristine conditions. The monitor was perfectly working, but the power supply and the main board had a plethora of issues that needed a lot of investigation to be found!
The RIFA filters have been immediately replaced. All the capacitors of the secondary reported an invalid ESR value, so I had to replace them as well. I finally turned on the power supply with some test load (3/4 IDE HDD that I use for testing purposes) to discover that one of the output voltages was wrong and to make it worse I had 0V output at random power ups.
The 6581 SID was burning hot, so it has been immediately removed. This is the only machine with a soldered SID.
