Sequencer issue and kitpieces not sounding

Just finished building my yocto and on switching it on for the first time I noticed that steps 1-3 buttons on the sequencer do not light up. 4-16 light up fine and I can step through these. Anyone have an idea where I should start looking at. I'm assuming this is an issue within the sequencer section. I've not tested the unit for sound yet as time was too short to allow me to do so. Any ideas will be greatly appreciated. Thanks

Ok so I've managed to test the audio and more trouble I'm afraid. Only sound is coming from the bass and hi hats. The volume through headphones seems really quiet too. Wierd electrical glitches come continuously from the maracas which can be volume controlled.
I did the service manual adjustment to the noise section but have not calibrated this to 130mv. Any ideas what is wrong?

Ok some progress I've found cold soulder joints on the buttons so the sequencer is working in this regard. But the following issues remain:
Only bass and high hats trigger with a sequence running.
Switching between the toms lets me hear each as I switch but these do not sound from the sequencer.
No sound from the remaining pieces. Oddly the cymbals don't sound but these calibrated as per the instructions.
No noticeable errors on the audio wiring.
Wondering if I have trouble with the noise section as the hand clap just produces continuous noise.
Anyone can post a picture of the soulder side of their working board so I can compare if I have bridges etc. Also should I start pulling ic parts now to check for errors with these?

Going from bad to worse sadly now no instruments are sounding. Perhaps I need to check out how each of these should be triggered. Wishing I'd tested each component before building.

fired up my tr-8 for some light relief.