Red and green LED behavior on the bench (CA18DET 36F05)

[hexdmy]

Can anyone verify what the two LED's do when powering a CA18DET ecu on the bench. I have one that appears to be bad, the LED's simultaneously come on and stay on with the diagnostic potentiometer turned all the way counter clockwise. When powering the ecu with the potentiometer turned all the way clockwise, the two LED's turn on for a half second or so then go off. I would like to have an idea of what is "normal" with one of these ecus.

Thank you.

[Matt]

With potentiometer 'off' (wires disconnected) the LEDs stay on

With them shorted together we see diagnostic mode (sorry I dont have a potentiometer on my S13 ECU since I removed as part of Type 1 install)

[Matt]

Do buzz check on IC1 (socket) to IC2 (RAM)

ROW1 (top from dot)

1 - VPP (Buzz to VCC @ 28)
2 - A12
3 - A7
4 - A6
5 - A5
6 - A4
7 - A3
8 - A2
9 - A1
10 - A0
11 - D0
12 - D1
13 - D2
14 - GND

ROW2 (bottom RHS upwards)
15 - D3
16 - D4
17 - D5
18 - D6
19 - D7
20 - /CE (buzz to GND @ 14)
21 - A10
22 - /OE
23 - A11
24 - A9
25 - A8
26 - A13
27 - /PGM (connect to VCC @ 28)
28 - VCC


SRAM chip

1024*8
+------+
A7 |1 24| Vcc
A6 |2 23| A8
A5 |3 22| A9
A4 |4 21| ?
A3 |5 20| ?
A2 |6 19| A10
A1 |7 18| CE
A0 |8 17| D7
D0 |9 16| D6
D1 |10 15| D5
D2 |11 14| D4
GND|12 13| D3
+------+

? would be R/_W and probably /OE

Other marked lines D0-D7 should buzz to the socket from RAM and A0-A10 lines. GND lines too (VCC line doesnt)