Pioneer QX-747 Quad Receiver from 1973. Detailed cleanup and re-bias video.

Picked this Pioneer QX-747 up locally for a great price last week. It was born in June 1973 just as me based on serial number decode. 100% original and in excellent condition after a complete clean out and amp readjustment. No need to relamp - dial bulbs are pristine and filaments have slight evidence of use.
Quad, 4x20WPC or 2x40WPC in 2 channel mode.
Might be the best engineered piece of equipment I’ve seen. Heavy as hell and built incredibly well, to the point of excessive. But that’s what makes these vintage pieces unique and a new marvel to enjoy as one would enjoy a classic car.
Tonight’s video is about 12 minutes long and will walk you through the journey of the baseline and cleanup/cleanout.
I’m not planning to recap or make any changes except I might restore the tone board. Upon cold power on for the first few minutes, the switch selectors and other controls can inject a little bit of DC into the signal causing a speaker pop. Once it’s on for about 3 minutes, it’s completely fine with no issue for the rest of the session. I believe these are probably bad little tantalum capacitors or known issue-prone transistors. I’ve seen very very similar issues in both the Pioneer SX-1050 and SX-980 receivers.
This thing sounds a hell of a lot more powerful than 40 watts. It’s really pushing my HPM-100’s tonight.

[@xruraldustx]

"I'm gonna guess nobody has been in here." I don't know why but I cracked up after you said that. I think because it felt like you inadvertently had undertones of sarcasm and humor.

[@gomezadams9900]

Hi Mark, I was wondering if you have ever come across a telefunkin; ( not sure of the spelling) receiver. It had lots of options built into it and I had it for many years until they couldn't find parts to repair it.

[@jonnietruth4083]

Wow… That’s a beauty. I would love to have that. But I have some nice stuff so I’m happy. 😊

[@danielapaul6753]

🤗🤗🤗🤗