Did you check your cables using other pedals

I’m not sure I follow are you saying with your 4 track fuzz disconnected you still get a squeal

You should get audio at pin 1 it being the output, you do sometimes need to mess around to get good contact with your probe

Is your guitar fitted with humbuckers or high output pickups

Sounds like it could be something to do with your power supply the only way to know for sure is to either get a 9v regulated and filtered power supply or use a battery with it being present at pin 3 ie audio into the op amp that tells me it’s there at the clean signal input and is then being amplified

Check if you get it on the pcb input pad and R1 and C1 that’ll let us know if the noise is there prior to going into the effects circuit

Typing at the same time Jeff!

That’s great it’s sorted

I always advise people not to go for the cheap option when it comes to pedal power mine are all boss filtered and regulated they cost 3 times as much but save a lot of hassle and unwanted noise

Make yourself a few of the battery snap connectors really cheap and always handy if your power supply goes South

Where are you located they’re cheap as chips at

https://www.bitsbox.co.uk/index.php?main_page=product_info&cPath=225_232&products_id=2365

With a battery you shouldn’t get any noise

A power supply will add noise from AC ripple if it’s not filtered and will put out more voltage if it’s not regulated very few cheap ones put out 9v I’ve had them as much as 14v

You’re much more likely to get noise with higher gain pedals I use a battery a cheap adaptor and a boss adaptor to demo my pedals just to show you can get significant noise with cheap adaptors most musicians don’t have the faintest idea how cheapo equipment can affect their set up

There is filtering in the circuit if you look at the power section C7 check that’s got good solder joints