Studer A730 CD player spins backwards

I bought a new eprom with the new files already loaded.
But Studer still doesn't work....😢
 

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  • IC33.jpg
    IC33.jpg
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As much as I can see on your photo, you did not replace IC33.

Please check its checksums with an EPROM reader such as this one https://xgecu.myshopify.com/collections/xgecu-t48-tl866ii-3g-programmer

Checksum should be the same after each read. If it is not, it means the EPROM contents is altered.

Here is what I found after 20 readings on my defective one, not a single identical result :

Capture d’écran 2025-06-11 065148.jpg
 
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I'll start by saying that I've tried the entire upper "half" of this one that I'm restoring (for me) in another fully functional Studer A730 of mine: the entire upper half works perfectly, so the problem is in the mainboard of which I've already completely renewed the power supply section.