Lost sound on a modified PAL Sony

[Skolink]

I've got one of those in my TiVo, complete with plastic box! Andrew Payne = CatDog
I've laid out an SMD version, and have most of the components. Just waiting on my friend (who still works in electronics) to get around to getting me some free PCBs. It's only been a year since I started on it...

Need a photo of my wiring?

[Lurker]

oooh yes please

I am almost convinced that this spare wire has come off the middle connection of 3 - the only problem I have is there is already a wire soldered to that connector going down towards the motherboard as a black covered wire inside the fat grey one going to the capacitors on the sound chip.... and I cant see the other end of that connected to anything on the motherboard as a ground

[Lurker]

Picture to add to confusion :-)

Left wire of 3 (blue/white) goes to power (+5v)
middle wire (black shrouded part of grey wire) goes down towards sound chip - other wires in it carry sound but cant figure if that black wire is attached to a GND on the motherboard and other blue white wire may have become unattached from this connection)
right wire (red) goes to +12v

[DOlsen]

oooh yes please

I am almost convinced that this spare wire has come off the middle connection of 3 - the only problem I have is there is already a wire soldered to that connector going down towards the motherboard as a black covered wire inside the fat grey one going to the capacitors on the sound chip.... and I cant see the other end of that connected to anything on the motherboard as a ground

The wire has come off the middle one. It's the ground, which needs to be connected for the circuit board to work. That's why, even when you hold the sif connection against the motherboard you don't hear anything.
Could have been attached at the other end of the audio wire I suppose.

edit - IE - the shielding of the audio wires.

[Lurker]

sweet! sorted.

Partner arrived home from Cello rehearsal and provided the requisite number of hands to hold the SIF wire to the board while I played with the ground.... a couple of short circuits later and got sound.

Going to drop in on my brother tomorrow and his handy soldering iron for a permanent resolder

thanks all

[Skolink]

Here are some photos of mine. cables aren't that tidy as I was intending to fit my own SMD version at some stage.

I should point out that I originally did a MKII audio mod, replacing the Micronas chip, but I think the SIF pickup point should still be the same.

I should also mention that the black wire you see coming from the white stereo cable is to ground the cable shield at one end only. The sheild should not be connected to anything at the other end.

[Lurker]

Thats brilliant thanks, it points out the bit that confused me.

On mine the ground audio wire and the ground wire to the PSU were both soldered together on the middle pin of 3 on the circuit board - which meant I could not see where the ground wire had de-soldered from.

[catdog]

Glad to see you got it sorted!

Sorry for the minimal documentation in the other thread about where the wires are actually soldered to - that board was one of the prototypes I put together, so I didn't see much point in providing step by step instructions since it was unlikely anyone would use them!