Biggest problem with those beside cassettte deck parts is the output chips. And they are not quite stand alone amps in alot of those 2000/2700s. With most of them you can't just pick up a preamp output. Moreso with the 2000s with the VF display and EQ, and the type D cassette. That is the one Blaupunkt admitted they built. I suspect they built them all but generically. The type Ds were really good but had a bad failure mode. The belt goes it will not eject. Then people got out the screwdriver and reallty FUBARed it up.
The output chips are the biggest problem with those. If you got one with all four channels working fix it, and never heavy load it. Use ten ohm speakers, not eight lol.
The FM is aligned by just tuning it in. This is from a guy who had factory training on them. He said the alignment was the easiest he has ever seen. It really is just tweak it. Adjust for maximum.
Actually, all the selectivity is in the ceramic filters, and the frequency of the local is PLLed, so all there are are a few coils that were necessary. Like transformers or whatever.
In the automotive setting, I believe the vibration throws it off by making the cores move. The position of those cores is what aligns. They move, not aligned anymore of course.
You MUST have the right tools to tweak those coils. DO NOT risk cracking the core, in fact maybe spray them a day before even trying.
The antenna lead is well insulated, select a very strong station in your area, hopefully a rock station that will stay up near 100 % modulation all the time. You want that. Start out with the wire an inch away and draw it away from the antenna jack. Tweak. When it sounds good again, move the wire further away and again, tweak.
This works for FM, and will for AM but it needs a properly matched antenna for that. FM is not picky. Do AM in the car if you can.
On the Delco, before you even start, find a strong station like say it is 100.1. Go to 99.9 and 100.3 and see if the distorted whatever stuff sounds the same. If it does not you have to align the detector. This is not documented, but you can align the detector by tuning it to where the distorted off channel signal sounds the same when off by exactly one channel. Left or right of thsat station off by one, sounds exactly the same. Thatis whe the detector is right.
The IF bandwidth is set and the local oscillator is set, end of story. You need no other reference.
One of the reasons this is so easy is because this is some kind of enhanced Shotz tuner that Hughes Aircraft and Hafler designed or some shit. It really is the best single antenna tuner out there for a long time. Not REALLY audiophile but damn close.
Of course for driving down the road with too much money, they got radios that have two or even three front ends and they switch dynamically lightning fast to whichever one has the best signal.
The "cheap" ones go by signal strength, the good ones analyze the mutipath.
That's all fine and good, but if you snash the car it is more ikely that the Delco will still work rather than a Cructchfield special.