You are misinterpreting the test on F-14. Each sound made from that test either uses the CVSD OR the DAC, not both simultaneously. The CVSD plays speech and sound samples. The DAC plays electronic sound effects.
No Speech (CVSD) but working sound effects (DAC) from the MPU section means only 3 possible bad parts.
CVSD at U3
1458 Op amp at U4
10 uf cap at C15
I supposed the 1 uf cap at C9 could go bad too but I have never seen it.
I have had to replace at least 10+ CVSD's over 15+ years so they do go bad.
If you aren't getting the DAC or the CVSD to work then it can be way more likely issues.
3 wire cable missing between sound board and cpu board
Bad 1458 Op amp at U5
Bad RAM on CPU sound section U23
Bad CPU at CPU sound section U24
Bad ROM's at U21, U22
Pinbot is a slightly annoying game to diagnose sound issues from because there were multiple variations on where the speech comes from depending on the build.
I have seen most pinbots with speech generated only on the Cpu board. I have seen 2 with speech generated on both boards and I have seen one that was completely missing the CVSD with several resistors in a socket at that spot and all speech generated on the background board. Some games have only U4 on the background sound board and some have U4 and U19. Sounds like yours should be a conventional Pinbot since it only has U4
Most games from system 11-11B had the speech generated only on the MPU sound section. Elvira definitely has the speech generated on both boards (Drac on one and Elvira on the other), and all 11C games only have the speech generated on the background sound board.