Yes, the testing conditions ought to work.
But now that you've reminded me, I think I did jump the gun. For review:
You've tested the voltages in the system already: +5, -5, and +12V are correct.
Atari expansion shows video and audio. So the RF modulator works.
No sound or video from Frogger. This suggests that the problem comes BEFORE the video controller. ROM, RAM, CPU, or glue logic.
You could verify that the VDC is alive using the pin listings, but let's also turn attention to U6, which is just under the VDC on the right side. This maps outputs to I/O ports. VDC and sound are both I/O ports, as are the game controllers.
8 7 6 5 4 3 2 1
9 10 11 12 13 14 15 16
1 is for port read vs write. If the CPU is alive (and it probably is), then you should see this blinking.
2-3 and 6 are address bus lines and should also be blinking.
4 is the I/O request line and should be blinking.
5 is for overriding the I/O ports. It should be low.
7 selects one of the controller ports. It will be high until the program starts looking for input, then blinking. So, option screen or later (but typically not while doing a death pause or whatnot)
8 is ground, so low
9 selects the sound chip. If you have Frogger in, it ought to be blinking all the time.
10 is not connected. Should be high.
11 selects one of the controller read modes (joystick, I think... never can keep them straight without looking it up). Should be blinking if the game is polling for input. Well, technically, software can do what it wants... it could, for instance, leave the controller in one mode or the other if it doesn't care about the other input type at the moment. But the ROM routine polls both in the same call, so if the game uses it, you'll get the blinking.
12 is VDC read. For Frogger, this should be happening from the time you turn the system on. So, blinking.
13 is VDC write. Blinking.
14 is not connected and ought to be high.
15 is the other controller read mode. So discussion about 11 applies.
16 is +5V. So high.
Edited by ChildOfCv, Mon Feb 25, 2019 2:34 PM.