I documented the changes to the Color Classic Analog Board to allow the board to operate at 640x480 without the transformer trace cut mod!
Here are the CORRECT changes, this allows for full width without any distortions.
CL9: Change from 3.3uF to 2.2uF 160V
CL10: Change from 3.3uF to 1.8uF 160V
DL21 and DL22 get removed and replaced with single 18V Zener at DL21. BZX85C18
RL62 Changes from 47Ohm to 100Ohm
RP61 gets 7.5K 3Watt resistor added.
J104 jumper gets removed and replaced with a 10 ohm resistor, 2 Watt.
RL70 changes from 33K to 22K.
RL54 changes from 33Ohms to 15Ohms
RP8 Changes from 15K to 33K
RP23 Changes from 22K to 33K
RF14 Changes from 236K to 216K 1% Precision resistor.
J78 moves to J79. (SMD)
RP6 changes from 4.52K to 5.11K (SMD)
I have yet to try these modifications on my CC board, HOWEVER these changes were performed on a DVT board by one of the head engineers, and the board is working properly at 640x480 without any distortions or width problems.
These were the ONLY changes found between the two boards. Also, DL21/22 does NOT overheat on the DVT board either with these changes, the changes never made it into production on the CC, but have on the LC5XX+
When i complete the restoration on the DVT board, I will post photos of a stock, and DVT. you will clearly see the changes.
Edited by techknight, 29 November 2015 - 02:38 PM.