thank you maestro. i think ive found a good place to study this craft, finally. its been a long and arduous search. keep up the great work, this video is an excellent source for someone like me just getting started by working on my first 2 projects, a kenwood 6600 and a kenwood 9400. im gonna be opening up them up today and i will probably work on them in tandem, workspace permitting.

This is one of the greatest learning video about alignment of a radio. The receiver is logical and the teacher is great! My humble thanks.

I worked my way through high school at a TV repair shop. As the low man on the totem pole, one of my jobs was replacing picture tubes. My usual practice was to take an alligator lead, clip one end to the chassis, and the other to a thin screwdriver. I'd slide the end of the screwdriver under the insulating cap to contact the picture tube's anode to drain off any charge left in the tube. There was one particular model where the chassis was NOT ground, and I got bit pretty good when I went to remove the anode lead from the tube. Lesson learned - don't assume the chassis is ground.

Tony, this was a very good video especially for those of us who are still learning the craft. I really appreciated seeing exactly where you clipped on the probes. Thanks.

Most Kenwood Equipment from the 70's was well made. I still have an old Kenwood "Audio Lab Scope" (1970 vintage) that still works. I re-capped it a few years ago. Still has the original semi's in it. It was my first oscilloscope,..so it's got sentimental value. I use it as a V-I component tester today.

Just amazing, could listen to your vids 24/7, so educational and very interesting Thanks for sharing. 👍👍👍

Great job, Tony. Excellent explanation of the schematic and tuner workings. Plus the invaluable oscilloscope shots so when we attempt an alignment we will know what we are looking at.

Tony you're truly knowledgable great learning experience.

Great video. I find these entry level systems sometimes more entertaining as they offered a lot of value with the level of performance. The theory of operation is just right in front of you with these systems.

This is a great video! You have covered some very important information and I really appreciate it. Keep up the good work!

Goodness Gracious ! Sweet, sweet closing piece. Have to pipe this through to the floor standings.

Nice one, Tony. Even as long as it was, I enjoyed this more than watching darn near anything on cable TV. I've got some gear that is finally needing attention. A Radio Shack 20 band EQ (with expander), a 20 watt Sansui receiver from the mid 80's, a Claricon 27901 Quad Receiver from around 1976, and a few other bits of kit. Plus I'm in the design mode of an all NPN based amplifier. I love a challenge!

I actually attempted to do this once (FM alignment) on my old Kenwood Kt-7000 tuner. I had no test equipment except for the Kenwood scope. I did it using a weak FM stereo station (in the middle of the dial) utilizing both tuning meters on the tuner and the tuners multi-path output. Of course I had no clue what I was doing but eventually I got it pretty close..at least I thought so. I remember the tuner had "IC and Crystal filter" (similar to the tuner here...). I had a schematic also, but at the time (I was 17 or 18) I had very little knowledge about how tuners work. It was an educational experience that I never got in school. :)

Thanks for a fine video Tony. It's always fun to listen to someone who knows what they are talking about. Cheers! 🙌👍

Very good informative video Tony. I appreciate all the tips and explanations.

Thank you very much for this good video and instructions. BTW, there is the schematic (no service manual) of this model on hifiengine (thanks for the person who uploaded that).

I have this same receiver and I had the exact same issues. Thanks Tony!

Wow, great session! Thanks.

This is a great video. Thanks for the info on discharging capacitors.

Nice work. As the elderly Asian lady said to Deckerd: "Finest craftsmanship". I like the felt spacers for the caps.

Excellent job Tony !

Love your 'shack' man ... i shoulda got a degree in electronics.. sigh ... and i love the stereo gear from the 70s n 80s .....Excellent video !

Great video Tony. I love the Kenwood, but the Dioxit and how to use it was the best part. So many Noobs will hose down even audiophiles do this too a bunch of know it alls so to speak. But I am glad you showed how to use Doxit right. It is not a panacea for all things that ail you. It is more preservative than cleaner. These boneheads I hang around with don't listen. So they get your link Tony. Maybe they will listen to you. Great video kind sir!

Nice job. I had a KR 3090. While not high end it sounded better than it should for the price.

Great Video and timing is perfect. I am getting ready to try to align a Realistic STA-90 having the same meter problems and no stereo. I only have a signal generator and DMM hoping to get it close. PLease please please more alignment videos it would also be cool to see only being done first with only DMM then checked with scope. Thank you

Hello Tony, I really love your work and enjoy seeing your videos on repairing and servicing vintage electronics. Can we please make arrangements to have you service my Pioneer SX-1280 receiver? It is in pretty good condition but I think there might be some things that need some attention. I enjoy owning it and I intend to keep it but I don't want it to break down because of lack of proper service. Thank you for your expert work and inspiration. Sincerely, Clinton

Thanks Tony 🙏

awesome Job!!!

@18:30 a wonderful capacitor discharge tool for high-voltage power supplies is a "Wiggy". Self-contained, electro-magnetic (because it uses a solenoid), simple, affordable, fast, and reliable. Because it puts the voltage across a coil in a solenoid which is designed for high voltages, the greater the rate of change in current (i.e. the surge of discharge current), the more it resists!

Tony would one day do a video on recapping some speakers. Thanks Rick

My 5400 found a tweeter problem in a set of speakers. Thought the issue was the amp. Kenwoods design was pretty smart...smarter than me for a week...

Coupling caps, decoupling caps, etc, 😊

Those discriminator coils are known to drift a bit after a few years. Sanyo (where I worked for 25 years) used the exact same ones.

Great video, can you connect a vintage Realistic equalizer to this receiver for listening to vinyl (phono 1 or 2), if so what do I connect to in the back ? THanks!

I like to use 1 kilohm per every 100 volts of capacitor (voltage) rating to discharge electrolytic caps in mains power supplies, mostly because it’s easier to find a 1 kilohm power resistor than it is to find an incandescent bulb these days; second, it’s easy to calculate the resistance needed; and third, it is easy on the capacitor and limits the current to (roughly) - at most - 100 mA. Safety note: you can also use your dim-bulb tester... as long as you UNPLUG it from the mains, first!! I’ve even heard of technicians using a programmable DC load to discharge the caps, but not everyone has one of those.

Many years ago when deciding What the QI should be. We always looked at the distortion residual waveform at 50mW output at 10Khz. This would enable you to remove cross over notches to below the residual noise level of the amplifier. Looking for the basic crossover spike on a sign wave does not really show the full story. Probably OK for a mid range amp like this but not really good enough for the better amplifiers.

Came back to your video , as i picked up a Kenwood model Eleven GX receiver and cant seem to find out what the Bias voltage suppose to be set to.... Receiver seems to run hot

Nice!

Great Video, thanks, you got that receiver sounding sweet again, quite a lot of time and expertise to get that back working properly, how much would you have charged for a repair like that?

Picked one of these up recently. Need to go over and clean everything, the only real issue is the volume will fluctuate after being left on for a while, using the FM channel, not phono or aux. Any ideas what could cause this? Thank you and amazing video on this cool receiver

Just wondering ,, what is your thoughts on the UNI-T UTE 1010A? Been wanting to get one,, getting a bit tired if pulling out DDMs and setting them all up just to do power on's. Another good vid!!

Rebuilding one of these as we speak which had the same issue... Your video helped a ton since there is no service manual.. Did you ever end up replacing Q5/Q6? Those 2SC1451's are on the AudioKarma list of one of the "REPLACE ASAP" or pay later list and probaly the worst of all of them. I replaced them as well as those 3 tarnished ones you did.. Almost done and hope this thing is playing happy music again soon.. What a pain without a manual... Your video helped a ton THank you!

Thanks for this great video Tony. I have seen this video and your video on the Kenwood KR 7400. The project I am working on is not a restoration, but a recreation of the tone-control and main-amplifier of the KR 7400, using the schematics in the service manual. The power supply I made for this amplifier is not according to the schematics. I have the tone-control and main-amplifier working well (65 Wrms max. output before clipping in 8 Ohm), but I have one remaining question for which I haven’t been able to find an answer yet on the Internet: the thermistors The1/The2 in the bias control (Vbe multiplier circuit) are specified as 5TP-41L, which is unobtanium. From studying the circuit I understand the thermistors to be NTCs, but it is not clear what the resistance value is of these at room temperature. Does anybody know? Otherwise it would be great if someone is able to measure the resistance of this thermistor type? My guess it is in the range of 10K to 20K. Any help is greatly appreciated. If anyone is interested I can give the list of substitute transistors I used for the main amplifier. Only the original output transistors I was able to buy (but beware for the fakes on Aliexpress, but that is another story). Also the dual opamp ICs used for the tone-control of the KR 7400 are unobtanium, but they are two 741 opamps in one package according to the info I could find. I tried uA741 opamps, but then the tone-control had a bandlimitation starting around 10kHz. In the end I used TL084 opamp ICs to solve this bandwidth problem.

20:10 - Couldn't you feel the resistor to see if it heated up during discharge?

Seems to be a lot of problems with older gear like this is Discriminator related.

Tony would BC212L transistors be a good replacement for PNP transistors and BC182L be a good replacement for NPN transistors, What about replacing the radio circuit with a Silicon Labs Radio chip and replace the variable capacitor with a 450K pot to work as the tuning for the Silicon Labs radio chip which uses DSP processing to do everything that tuner does using desecrates just an idea.

what tool do you use to turn the vco pot? how do you connect the cable of the stereo indicator? Thanks

Can you look at the data sheet for the power transistors maximum gain voltage and adjust your pot accordingly to this to get the perfect adjustment On the scope is there no website that has the volatile ROM you can copy and we burn a new ROM

I have restored a couple of Kenwood amplifiers. It always strikes me how 'empty' they are, compared to most other brands.

I recently bought one and I am planning to change it to a 3 prong connector. Do you have a diagram to do it mantaining the switch and unswitched courtesy conectors?

These lower end receivers have so much headroom built into them that if you poured gasoline over it and set it on fire while it was working hard, it would probably keep pumping out the music for at least half an hour before the music stopped... You know that scenario, having a party and someone spilled some vodka into the guts of the amplifier and a nearby cigarette ignites the fumes being evaporated off the hot heatsink and boom! Instantly you are playing the hottest music in town lol... Direct from your vintage album of 1982 Up In Flames! Man, those stabistors are going to be working hard to keep the heat down lol... It's almost like I would love to know how long some of these amplifiers would work if they were actually set on fire but at the same time I couldn't bring myself to do it... But I would definitely not hesitate with some of the newer excuses for a stereo amplifier that have been sold to people as supposedly high quality gear... Kinda like those videos where people connect speakers directly to mains voltage to see which on wins by surviving the longest lol... If you wanted to go viral! Then this would be the way! I personally don't know of anyone that has done a video on... Two popular cheapo's going head to head on fire! It's a race to the death and all bets are on!

Question, I've got a Techtronic. 454 scope. Would that work out for this kind of work? Also is a pulse generator the same as a signal generator, or would it even work for this kind of stuff?

I have a 5400 that quit on me today. I was listening and it just went dead. It's not powering up now. Any ideas?

I just picked up one of these and very clean. But Noticed that most of the time it wont tune into a STERO signal and lamp not lit... But if i turn tuning knob to the left sometimes it will light up and tuned into stereo... ,, but if i turn knob to the right to the station it wont tune into stereo .. weird

Too bad this isn't a KR-9600.. I'm working on one right now.

Are you going to take this receiver (and other things you mention) to Galaxie Electronics in Squirrel Hill Pittsburgh?

1:21:48 - Why not just use an analog meter (VTVM) in place of the scope? It's *MUCH easier to monitor the relative level with an analog meter than trying to figure out the relative amplitude of a very noisy signal on a scope!

Having a problem with eye tube If you could look at my video And tell me what going on Video name jr mcloud

5:40 - I would have tested ALL the transistors BEFORE power-up!

A large can of WD 40 contact cleaner is less than $8.00.