Chris wrote:

Thanks, I will have a look at this carefully! I don't think I bent anything there but it is possible whilst the transport was upside down. I did place it on a flannel to try to protect it everything. Would it likely be bent too far inwards or outwards?

Downwards. So it hits on the front edge of the cassette.
Check if it will engage with no cassette inserted. 

Chris wrote:

On a side note, the little brass fan type thing, that spins around as you eject a tape. What exactly does that do? Is it a type of governor to slow down the tape eject? 

Yes, It's an airbrake.

Martin

Had a look at this. It seems fine I think.. I'll attach a photo when I'm back on a proper computer. 

It doesn't try to enagage without a tape in there. 

The intention was to see, if it would engage and stay engaged if it didn't hit the cassette, so you will have to hold the switch
at the back of the cassette tray to simulate a tape inserted.

Martin 

I pushed the switch (the light comes on and stays on solid, and without a tape in there it does nothing so I imagine this switch is okay?)... the same behavior is observed when I manually push the switch and try to play the tape, clicking in and out a few times and then engaging and playing.  :( 

Again once playing/fast forwarding etc, it will play happily. 

When I replaced the belts does anything need to be lined up for it to work correctly? I couldn't see a reason why anything there makes a difference be but best to check. 

Nothing needs aligning when replacing only the belts.
If you also replaced the idler rubber parts, the brake arms etc. needs to be on the correct sides of their respective flanges - the
front right one being the one most often ending up on the wrong side, resulting in it getting bend and losing its small felt pad.

When the deck tried to play, does the take-up reel rotate and take up - even for just a brief moment?

Martin

Hi Martin,

That's great, hopefully all else is okay as the mechanism moved freely and I only replaced the belts. 

Yes it takes up around a 1/4 turn I would estimate however the head contacts the tape for literally a fraction of a second. 

Thanks a lot for the help :) 

Chris