RobertCX
Second RCA CDP18S020 up and running
I've now restored my second RCA CDP18S020 board, and have configured it to work with my RCA CDP18S021 Microterminal. This board was actually in better condition that the other one, with less cut tracks and a cleaner prototyping area. The only real issue was the sticky goop on the middle of the prototyping area, which was an absolute b*gger to remove, and this has left some minor abrasions on the PCB surface (as can be seen in the photo).
I've sourced a nice vintage NOS ceramic CDP1802D CPU, which complements the banks of ceramic RAM chips and matches the small CDP1824 utility RAM in style. One row of main RAM is empty because it only came with 24 ceramic devices, and the remaining plastic devices have been fitted to my other board - I am unlikely to need more than 3K if I'm just typing in programs via the Microterminal! The only rather "boring" LSI component is the UT5 monitor ROM (CDPR522), which though of original RCA vintage, came in a bland black plastic package instead of the nice ceramic ones you often see.
After restoring the board, I temporarily fitted the UT4 monitor, and uploaded all my RAM test routines. After these checked out, I then switched it to use the UT5 ROM and Microterminal. The RUN U button was already missing, and I also removed the RUN P button, as this should be done when using the Microterminal; this has its own RU and RP buttons to perform the same functions.
This is the "museum exhibit", while the other board is my working version, as it is more useful running UT4. I have been waiting to get one of these boards for a long time, and I now have two, plus the unbuilt kit and two Microterminals!
Second RCA CDP18S020 up and running
I've now restored my second RCA CDP18S020 board, and have configured it to work with my RCA CDP18S021 Microterminal. This board was actually in better condition that the other one, with less cut tracks and a cleaner prototyping area. The only real issue was the sticky goop on the middle of the prototyping area, which was an absolute b*gger to remove, and this has left some minor abrasions on the PCB surface (as can be seen in the photo).
I've sourced a nice vintage NOS ceramic CDP1802D CPU, which complements the banks of ceramic RAM chips and matches the small CDP1824 utility RAM in style. One row of main RAM is empty because it only came with 24 ceramic devices, and the remaining plastic devices have been fitted to my other board - I am unlikely to need more than 3K if I'm just typing in programs via the Microterminal! The only rather "boring" LSI component is the UT5 monitor ROM (CDPR522), which though of original RCA vintage, came in a bland black plastic package instead of the nice ceramic ones you often see.
After restoring the board, I temporarily fitted the UT4 monitor, and uploaded all my RAM test routines. After these checked out, I then switched it to use the UT5 ROM and Microterminal. The RUN U button was already missing, and I also removed the RUN P button, as this should be done when using the Microterminal; this has its own RU and RP buttons to perform the same functions.
This is the "museum exhibit", while the other board is my working version, as it is more useful running UT4. I have been waiting to get one of these boards for a long time, and I now have two, plus the unbuilt kit and two Microterminals!