Pioneer TX-7800 Tuner Alignment procedure - HELP!

[Krešo]

Hi everyone,

is there anybody here willing to share those few pages for FM/AM Tuner Alignment from the Pioneer TX-7800 Service Manual? Scans or photos of those few pages will be more than enough.

I found out out there a few SMs online but all are missing those pages. I am still searching around on many different places. I did find it's big brother thou, a TX-9800, with all pages and the procedure but since I am not an expert I can't be sure are all the values and steps exactly the same.

I have a tech with all the tools and knowledge who is willing to align it but he also doesn't have those pages.

I appreciate all the help you can give me.

Thanks all and stay safe!

Krešo

 

[markthefixer]

I struck out, hifi engine , the 64gig rick's as well as my eclectic collection. No alignment instructions....

 

[Krešo]

Hey Mark! Thanks for chiming in. And huge thanks for checking your stock. As it turns out to be there's plenty of SMs out there on many different platforms but all of them are missing FM/AM Alignment procedure. On the other hand, it's big brother TX-9800, has full SM with all inside. Since I am not absolutely sure will it work on my TX-7800 I decided to buy one. Luckily I managed to find it with a little help of a Tapehead fellow user. When I spot a physical (paper) copy on eBay or someplace else I am going to buy one and be set for life with it. I did manage to find original SMs for a few Pioneer stuff I have. Such a big idfference from poorly scanned ones floating around. In lack of better option those are fine too but original SMs usually have a lot of extra info in small print or different coloring written all over the schematics which is usually lost when scanning as a line-art. I get it, line-art is super small and can be compressed so it doesn't waste space. But sometimes we really need that color, small, fine print.

 

[zebulon1]

Even having the SM alignment info handy isn’t going to help that much. The info in the service manual is based on general knowledge the techs had at the time. Experience on other models and the available tuner technology.
Your search for the holy grail of a 7800 alignment procedure is going to be a disappointment.
Look and find other tuners with the same topography and see if you can glue together a procedure. Your buddy with the equipment should be of help in this.

 

[Krešo]

Sure. Me finding an original SM with the entire procedure explained is a way of helping him as much as I can. He's got skills, experience, equipment, he's done probably a bunch of them but detailed Pioneer's procedure can't hurt. That is why I told him I will do my best finding an original SM. I am pretty sure similar Tuners of that era, of similar topologies and performances are done more or less the same way. But I think having an original manufacturer's procedure will be of great help to him. He has been looking around too but he ended up finding the same as I did before I manage to buy an original one. Thanks all for all your help and insights! I really appreciate it!

 

[zebulon1]

A rant that is slightly off topic:
I can't remember anymore if it was the intriguing RF or the mystery of the little components that got my interest.
The RF is now front and center. This past year brought new insight, although not exactly how I wanted it. Several receivers on my bench had RF/IF issues. All expensive units that had to work.
After getting through the worst, another arrived. I'm beginning to think there are age issues that are starting to materialize?
Other learning factors are the fast moving tuner technology of yesteryear. From tube to solid state, discrete circuits to using chips must of made those repair techs go crazy.
Regardless, It was a motivating factor to start wrapping my head around the mystery's.

This forum has several members that can help and have the knowledge to offer guidance. They have helped clarify the circuit and or helped narrow down to a particular circuit. I requires a lot of self learning to understand how it all works.

 

[Krešo]

In case a buddy of mine finds himself in a pickle I am sure he will seek guidance here. I think he is aware of AK and great many people here with skills and life-long hands-on experience in this field. I simply don't want to leave the tuner out of alignment since it worked, and still does for that matter, flawlessly it's entire lifespan. Now age is getting the best of it and I am confident proper refresh and alignment will give it many more years. Those babies were made to last. Heck, I am quite sure none of the manufacturers of these commercial products such is Pioneer and others ever dreamed that their products will work with such precission and quality for such a long time! In fact I am sure of that! Take any product, tape decks, cassette decks, Amps., whatever... Decades and decades later all works like a charm.