First of all I would like to apologies for posting in the wrong thread. I started in the ""Horror Room" Symptoms of Bad CIs" thread but I couldn't proove it was a faulty IC somewhere so I created this new thread.
For those who starts reading this thread form there here's my problem. When D4/D5 sockets are fully populated with shift registers (I'm using the TO-99 package MM1404AH and they seems to be working) my terminal section starts to delete all the characters from screen resulting in a very fast screen scrolling up. If I put a 0.1uF capacitor between D4a pin 4 (-5V) and D5 pin 8 (GND) screen stops scrolling up but the clear screen won't clean the cursor shift register. I also have a ram issue, when all 16 sockets are populated the high nibble of every byte is corrupted (in reading it outputs "D" or "F" only).
If only bank X is populated (0000-1000) ram works but it loose data.
I also had a spacing issue on screen that I was able to solve today, the 0.001uF was broken and replacing it solved that problem. I also changed the 27k resistor with a 22k resistor and I made myself sure to have a 47pF capacitor near the 74123 (B3). The value of this capacitor is exactly 47.5pF (read with my tester) but still no luck. I asked a friend to help me measuring this capacitor in case my tester is not good and the capacitor has a different value. The electrolitic capacitors I'm using are 2 x 2200uF by Vishay and a 4700uF capacitor in place of the 5300uF one. I tested ripples with my oscilloscope and they seems ok. As dram chips I'm using 16 x TMS4116 by Texas Instruments. I suspect some problems with my -5V line because it seems to activate the fake cursor killer circuit, anyway I've done a test and since I'm using an smd replacement for the LM323k I lowered the output voltage from 5.00V to 4.81V and shift registers seems to be more stable. Do you think this could be caused by a too weak trasformer or do I "solved" something by lowering the voltages?