Poly-800 help needed

[Roman Sowa]

Hi all good ppl

Yesterday I tried to download patches thru Korg's weird tape interface
and failed every time.
I did this: recorded current settings as 16-bit 44.1k wav, and played
it back (all switches - tape, program and seq - switched to enable)
in verify mode. The biggest succes was when 'Err' message appeared
at the end of download (sometimes in the middle). But it simply refuses to
read it.
what am I doing wrong? Is this common? Is my Poly broken?

I'd appreciate any suggestions.
Does anyone have schematic of it? Only this part with tape front end?

thanx
Roman