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Twilight Zone - sub not working

Durzel

Registered
Joined
Oct 1, 2017
Messages
2,041
Location
Bath, UK
Installed a Flipper Fidelity kit on my TZ this weekend. Everything went fairly smoothly, with the only snag that the audio board connector the instructions told me to remove ("lower right", which is J504) had what I think is the sub negative wire. It had one wire coming off of it.

J505, which I replaced, was connected to the speakers and via a 1 pin connector to the yellow/black wire that goes down to the sub.

Switched everything back on and there was no "pop" on power on like it always used to do. Did a test and the backbox speakers work, but nothing comes out of the sub.

The black wire from J504 is going into the negative terminal on the sub. The yellow/black wire is going into the positive terminal.

I tried swapping the terminals around and nothing changed.

I also tried swapping J504 and J505 connectors over, with no change (backbox speakers work, no sub)

I took both fuses out on the audio board and tested their resistance and they both seemed ok.

I also tried putting the old speakers back on, but strangely they didn't work at all?

The circuit for the sub looks like it ought to be very simple - a black wire that comes off J504 that goes directly to the negative sub terminal, and black/yellow from the sub positive to the 1 pin connector coming off J505?

BD7B8AE5-FC01-4ABC-A254-6C078C0A1DAE.gif

2D8EC9CB-8934-40F5-B3FF-E372020FF454.jpeg

Is there anything I can do to test the sub works? Resistance etc?

Is it conceivable that the audio board could fail in such a way that both J504 and J505 work, but the sub doesn't? To reiterate - the backbox speakers work with the connector coming off them in either J504 or J505.

Thanks in advance for any help provided.
 
Something is very weird here.. just looked in manual for the audio board and it's got this:

81FD08E1-DF6C-405D-837D-6D6934242485.jpeg

Now if I'm reading that right, pin 3 on J504 is the black wire to sub connection? But the connector on mine it's on 2?

And even more confusingly I took this photo before I started doing anything and it worked then? Or at least I think it did - the OEM sub is so crap. It made a pop when I used to start it and switch it off, and now it doesn't.

13AC9779-9176-4836-8EE0-DF509D7EB1DB.jpeg
 
Fixed now.

Repinned J504-2 to J504-3 with a little screwdriver (need IDC tool) and sub started working immediately.

So basically my sub must've never worked? lol
 
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