That looks like a standard audio transformer to me, i don't know what from as my background was industrial electronics.
It would be used to isolate the audio signal between 2 different circuits.

Why do you think the DV74HC132AN will not be the same as the 74132 you need ?
It can handle up to 7v supply and you have 4.8v supply in the scope.
If the chip can handle the voltage and signal then it should be ok.
Hopefully someone who knows for sure can jump in with an answer for you.

The LM358 dual opamps will come in useful in many projects, you could use one to buffer the sinewave output of the ICL8038 signal generator IC that you got there.
The ICL8038 has square, triangle and sinewave outputs and will make some great signal generators for you to build.

Well F F F F Freak me out.
I wonder if there are any Bass amps in there, with 1000 watts D class powered speakers it would be great if there are several Bass models included.

Light bulb on top sounds like a photo transistor of some sort.
The 4 lead SK3006 is a Germanium transistor that has an extra leg for the metal cap on top as far as I know, and the SK3004 is also a Germanium transistor.
Some Germanium transistors are becoming expensive since they are no longer available and are very coveted for Fuzz pedals.

You should test all the Germaniums individually and record the findings.
https://www.radiomuseum.org/tubes/tube_sk3006.html

Datasheet is too big to upload here so here is the link:
http://bitsavers.trailing-edge.com/components/rca/SPG-202Z_RCA_SK_Series_Replacement_Guide_1981.pdf

Look at page 26 for the SK3004 and SK3006

Quote from: saturated on October 14, 2023, 10:25:03 PMI also learned that wires have two ends.  meaning all the while I knew to stay away from the wires on the end of the CRT.
I should have known that the ends of those wires are in the top middle of the following photo.

You will quickly learn to be careful if you touch those "hot" wires, but don't worry, it only hurts till you pass out.
You just need to worry about waking up after you pass out, it's not guaranteed.

The first thing you should do is make sure the speaker is not connected to that output as it will most likely destroy it.
The next thing after that is a bit beyond me at the moment.
Best of luck with it.

Here is a later service manual :

That potentiometer is meant to rotate fully around, it is made that way.
That one has no inbuilt stops on the shaft.

Did you put a knob on the shaft before you tried it ?
Some of the older ones might need a bit more force to turn the last bit so it activates the switch.

That part number is given as a substitute part for a Peavey Studio Pro 40 in this article:
https://www.ssguitar.com/index.php?topic=1593.0
I have no idea if it is accurate or not

I am not sure if this is the same or if you can get it but its available in Italy.
https://www.folliemusicali.com/prodotto/fender-outlet-0057799000-pcb-udsp-micro-dsp-for-deluxe-90/

USA:
https://reverb.com/item/67584695-fender-dsp-board-with-processors-2002

If you think the fault is in U4 then see if you can get a new chip and have someone copy the program from the 100 amp into the new chip, it is only an Eprom.

Here is the link to the other site pa911 mentioned :https://music-electronics-forum.com/forum/amplification/guitar-amps/maintenance-troubleshooting-repair/986153-fender-acoustasonic-30-dsp-with-very-audible-hiss

I can't help but someone might be able to.

And the schematic: You cannot view this attachment.

If nothing else comes out of it, the experience you are getting out of this is priceless in the long run.
Keep it up.

Edit: And most likely cheaper then spending your time in the local bar as well.

I tried to clean up the pictures, I don't know if it is better or worse.
Also some data sheets.

I think it would be a very big step to try to understand "Logic IC's" from the start.
There are several websites to learn from, and also many books and information on the NET that can guide you on the subject. Texas Instruments have some good info but it might get complicated very fast.
I would start here : https://learn.sparkfun.com/tutorials/digital-logic/all

The first picture shows you have a +4.8v supply that goes to 4 IC's (IC-301 to IC-304)
Pin 14 on the IC's is the positive voltage supply pin (Marked VCC)
Pin 7 on the IC's is the negative voltage supply pin (Marked GND)

In schematics VCC is often the marking for the positive supply, GND is the ground or 0V supply and finally VDD is often the negative supply.

So basically it just shows you have +4.8 volts to pin 14 on those chips and 0 volts on pin 7.

The second drawing you did is of IC303 (SN7472), it is a block diagram of its function, that IC is a "AND GATED J-K MASTER-SLAVE FLIP-FLOPS WITH CLEAR AND RESET".
What that means is that that is the very deep end of the pool for you where headaches lurk, you can try to understand it by reading up on it, I do and it gives me a headache even thinking about it.

All of those logic IC's have modules in them, and the modules are drawn with different symbols that indicates what they do, if you deal with them often its easy to follow but its been to long ago for me to try.

You might not be able to get the exact replacement part for all those IC's but there are many other chips that can do the same function with slightly different part numbers.

I found this page with lots of info on other model oscilloscopes, but not your one.
It is possible they might have very similar schematics or even the same.
Have a look :
https://www.vintage-radio.info/heathkit/index.htm

and just as I was going to press "post" I found these photos:

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It's best to open the pictures in a new window, or download the link when on the small pictures.

Heathkit Cross Reference:
You cannot view this attachment.

Whats the model of the Scope ?