Somewhere in my stash of transformers, I have an Output Transformer for either a Grundig or Telefunken unit that is similar to your Blaupunkt. We tried finding a replacement for a bad transformer here in the states to no avail, but a phone call to the AAFEEs TV repair guy in Germany got us one in the mail - this was in 1984! I still have the October 27, 1984 International Herald Tribune that was used to wrap the new transformer for packing. Interesting snapshot of history - George Schultz was the Secretary of State, Mondale was running for prez, and the Pope's would-be-assassin was in the news as well. We never did get to fix the unit - the guy lost interest in getting it fixed.
Interestingly enough, a guy at church keeps offering me one of the console Grundigs from the 1960s. It works fine, but I can't get him to name a price, and I don't want to lowball him and p*ss him off. He knows I'm interested, though. Really nice codger - in his 80's and still active!
Really nice resto job on your Blau! You should be proud!
Cheers,