Marine band Steve baker special Key of A top notes don't sound. Need setup tips

I ordered a Key of A Hohner SBS and when it cam I found that the top 4 holes (all the extra holes) don’t sound. I can occasionally get a shriek like you would get from a badly executed overblow on a poorly set up harp, but cant get any of the musical notes it should be making. When setting up harmonicas in the past I’ve never had to do much above hole 7 so I need setup advise on how to get the strongest sounds from your high notes. Any technique advise to get better sounds on the keys top octave would be helpful as well.

I guess you have checked the gapping, etc.
Could there be interference between the reed and plate?
Are the reed placements correct and tight?
I’m probably just telling you the simple stuff you already know well,
but I thought I’d start with the simple things.
I presume you are using the appropriate air pressure (never too much) for a good tone.


A Steve Baker in “A” is pitched pretty high, isn’t it?
Extra high is more difficult to sound sometimes. Takes some finesse I guess. LOL


Yeah SBS a is High, It starts at the regular place but gives you more than an octave above the high note on a standard A diatonic. I have played with the gapping a bit and gotten all but the top two holes to sound but the top two holes are still dead. Part of my problem is that when it comes to gapping, I’m not sure how much is too much and what is not enough on these extremely high notes. I know what is in the ballpark for a standard diatonic and once I get close I can fine tune untill I get it perfect but with these high notes I don’t know what is in the ballpark so I can’t get any sound and with no sound there is no fine tuning to get it just right. So it could be both my technique and gaping and when I’m getting no sound at all I don’t know which to work on 1st.