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.

Best advice would be to remove the ribbon cable from the sound board to the cpu board. Then go into the sound test though the diagnostic menu and see if the game makes any sounds. If it makes some sound effects but no speech then it's the 3 likely components on the mpu board. If if makes no sound at all then it's the slightly harder repair on the MPU board. Double check your work by reattaching the ribbon cable and rerunning the tests. If this is a standard build pinbot the music will be all that is generated on the background sound board through the ribbon cable (and that can be tested in the music test) and all game play sound effects and speech will be generated on the MPU board.

order of likelihood for the no speech but sound effect result
1458 Op amp at U4
CVSD at U3
10 uf cap at C15
but the cvsd is the most $ and hardest to find part so swap that last.

order of likelihood for the no speech and no sound effect result

Bad 1458 Op amp at U5
Bad RAM on CPU sound section U23
Bad ROM's at U21, U22
Bad CPU at CPU sound section U24
3 wire cable missing between sound board and cpu board

I have plenty of old posts on system 11 sound generation but here is the skinny

Depending on which version MPU and which version sound board there are up to 6 different sources of sound.

On the MPU board
Speech from 55536 CVSD
Sounds from 1408 DAC
(these are both removed on system 11C but are used on 100% of the time on system 11, 11A and 11B games except for that one weird pinbot I found)

On the background sound board

Sounds from 1408 DAC (pretty sure it's always populated) not sure if it's always used. (this is the only sound line on High speed and Grand Lizard background sound boards)
2 sound lines from the Yamaha Synthesizer chips these start from Road Kings all the way through 11C)
Speech from 55536 CVSD (not populated on most games, but always there on system 11C, pinbot is the first sound board that has a location for it)

The fully populated system 11 sound board is essentially the same as the first gen WPC pre-DCS sound board in terms of how the sounds are make (same CVSD, DAC and yamaha chips) it just used a different amp and different way to talk to the MPU board.

Strange. 00-07 are supposed to test the speech AND the sound effects. Both are generated on the MPU board. the speech from the 55536 and associated components and the electronic sound effects from the DAC (1808?? I forget the part number the moment). Can anyone else confirm that 00-07 is more than just speech samples or sampled sounds versus electronic sound effects?

If the MPU driven sound effects are working then the CPU, RAM, ROM's etc should be OK and you are just looking at the 3 speech only components, (1458 op-amp, 10 uf cap, 55536 chip)

06 is definitely speech. He says "tilt" 07 might be a sampled sound and thus speech . 00-05 sound like sound effects.

yep, the 55536 produces sampled sounds; so speech, animal sounds, explosions, etc.. op amp and 10 uf cap first, then the 55536 if it still doesn't work.

can you post pics of your sound board and the sound/speech section on your MPU. Pinbot was delivered in at least 3 variations for the sound/speech/music set-up

yeah, that's the most common standard configuration (speech on MPU, no speech on the background board, CVSD at U18 is not populated).

One other easy test is to jumper the sound effects/speech from the MPU to the MPU amp without the background sound board connected.

remove J116 from the MPU then pull the connector of the sound board that goes to the volume knob and connect it onto J116. this will make the audio signals from the MPU generated sounds bypass being mixed into the background board. With this done we can see which of the sound effects are coming from the DAC on the MPU board and which are coming from the DAC on the background sound board.

My thinking here is that if you aren't getting any of the sounds from test 00-07 then what sound effects that the game is making are in fact coming from the DAC on the background sound board. If NOTHING is being generated on the MPU sound section then you still have the other op amp, the RAM, the eproms and the CPU chip that might be bad (usually in that order)

Here is a pic of the weirdest set-up in a pin-bot. No CVSD on the MPU board and a speech chip on the background sound board. I've also seen it set-up with speech on BOTH of the boards (verified that it indeed generated from both spots)
https://pinside.com/pinball/forum/topic/pinbot-u19-speech-chip-whats-it-for#post-2296540

Go ahead and do that too. Likely those sound effects will be as faint as the music. If so then the entire sound section on your MPU board is NOT working, not just the speech. So it's likely one of the following on the MPU board sound section (in order of likelihood from my experience);

the other 1458 op amp, the RAM, the eproms and the CPU chip that might be bad

You have TWO DAC'S in the game that generate electronic sound effects.

Read up on some of my old threads on system 11 sound to get the full story. Short story is this.

System 11 generates up to 6 different sound lines. Very few games will have all 6 (EATPM is one). These 6 outputs are;

2 different speech sound outputs from 55536 CVSD's. 1 on MPU 1 on background sound board
2 different sound effect outputs from 1408 DAC's. 1 on MPU 1 on background sound board
2 syntheziser sound outputs from 2 yamaha chips. Both on background sound board.

Your Pinbot has 5 outputs. The only one missing from the above list is the background board speech.

When you disconnected the background soundboard generated audio you can still hear it faintly because the audio amp is picking it up through the ground plane. What you are hearing faintly are the 3 (out of 4 possible) sound lines from background sound board.

Usually you can swap the CPU chip's on the MPU board (both 6802 or 6808 chips). If the sound CPU is bad then likely the game won't boot when in the main CPU slot.

Sound eproms U21 and U22 can be at fault and are an easy swap in. U19 AFAIK doesn't do anything at all. Someone else on pinside ordered one and put it in and nothing was different. Wonder it if moves some of the sounds/speech from the MPU to the background sound.

My experience shows that usually a fully dead MPU sound section is the RAM.

Double check all the rework you did, especially the sockets.

As to the static/intermittent issues:
The music and backgroundboard sound effects never goes to the MPU board. It's goes out to the volume knob and back and then goes to the speakers. I don't recall you doing any work on the background sound board through all this testing. Check the volume knob and the wire connectors going to it and to the speakers.

To the missing speech there isnt much left to check. If you have known working processor, RAM, ROM's, op amps and new correctly oriented caps it should be working. Where this sound gets mixed on the background sound board would also cause all sound to fail if that op-amp was dead. Maybe a dumb one but did you check the wiring on the 4 pin connector between the MPU and sound board (red/white/black wire J115 I believe). If this is damaged or missing no sounds will transfer from the MPU to the final amps on the background sound board.