Dragon 32 Upper RAM Fix (MK II Boards)
If any doubt take your Dragon to a professional! It is very easy to destroy your Dragon with poor soldering etc.
The video and download helps you diagnose and locate faulty 4116 chips in the upper 16K of RAM on Dragon 32 MKII boards.
The example in the video shows where a chip has a completely failed, in some instances it could just be a single bit, in a single byte, which is more difficult to locate but below is a BASIC program that can be used to help find the faulty memory location.
BASIC RAM testing program download, also checks 12K of the lower RAM.
***Before*** loading or typing in the memory testing program enter the following into BASIC:
PCLEAR 1
CLEAR 100,3999
Once the faulty memory location has been identified use the POKE and PEEK method shown in the video to find the faulty bit/chip but using the memory location identified as faulty. N.B:
Lower 16K : 0 – 16383
Upper 16K : 16384 - 32767
Thanks to Phill for QC