A customer in the US is scratching his head trying to work out how the output jack (stereo) is inserted in the hole.

I did get one out to have a quick look and it does look appear there's a bit of work to do... perhaps filing out the hole to allow the jack to slide into position.

Here's the part alongside the hole where it sits. The hole comes out in the control cavity.
Click image for larger version.  Name: IB1 front pre.jpg  Views: 272  Size: 171.9 KB  ID: 15932

Here is where the customer is stuck:
Click image for larger version.  Name: IB1cust.jpg  Views: 280  Size: 554.9 KB  ID: 15933
Note: the washer behind the tip is rubber, so it does seem that it will all sit comfortably in there, once you get it in place. It's all just a bit too tight.

And here is the view on DB's finished IB-1:
Click image for larger version.  Name: IB1 front.jpg  Views: 290  Size: 243.3 KB  ID: 15934

If anyone has done this job, can you please let us know the 'trick'. Then we can save this as an instruction thread for future IB-1 builders... assuming there isn't one already.

Thanks for your help.