You have the patients of a saint. I use to drool over this receiver when I was a kid at the Hi Fi shop. Back in the 70's we were too poor to afford such an expensive awesome thing. I remember the sound of the soft jazz they were playing at the store, nothing we ever had sounded so good. They were amazing receivers in their day. After what you did to this receiver I'd say it's new resale value is at least $7,675.00. This one should be in a audio history museum. At least now you know how much you should charge for a restoration like this.
We don't often get to see a Quad adventure like this one; time patience, and experience won the day on this unit. I hope you and family had a Merry Christmas and best wishes for the New Year. Thank you for your time!
Trevor (greetings from the West Coast of Canada eh!) I thought you had patience and perseverance on some previous configurations...............but this 'takes the cake'!! I personally cannot see the rationale for the owner to want to have this unit fully restored and the fact that you stated at the outset that with the complexity of this model - your rate $$ would double! There must be some high nostalgic or personal reason to compel the owner to have you spend the time and his/hers $$$ to have this restoration completed. On your part - well done! This established a high-water mark as to your abilities (et al)!! It would be interesting as to the total hours you spent on this restoration and the $$. PS - you viewers who keep stating Trevor's Vids are too long - to you I say 'get lost'! Trevor. Thanks once again for a great year of vids. Health and Happiness to you and your extended family for 2025 (and well beyond) PPS. I wish you were located in 'my back yard' - I have a Marantz 2325 that could really use a 'Trevor Touch' restoration - Ha!
You're a braver man than me ! I think that must have been really expensive for HK to build and even more expensive to service when it needed any work just because there is so much crammed into the chassis !
According to a former H/K technician on the QuardraphonicQuad forum: "The 900+ (and the 100+ & 150+) was designed by H/K in the USA but custom manufactured exclusively for H/K by a company named "Crown Radio Company" in Japan."
@@ian-c.01 The former tech, 4morhktech, on the thread: RCVR: Harman Kardon 900+ Quadraphonic Receiver at QuadraphonicQuad forum does not address the sales figures but does state the following in a reply: "Yup, the 150+ came out in 1972 and was discontinued in late 1974. The 900+ came out in 1973 and was discontinued in late 1975. There was an overlap when both models were being produced. The 900+ did not really replace the 150+. All remaining H/K quad models were discontinued due to lack of software support in late 1975... insufficient numbers of recordings were produced by the major record labels to support 4-channel hardware sales. As a matter of fact, H/K was supposed to come out with another quad receiver, the 700+. The 700+ was first destined to be built in Puerto Rico, then that changed to Plainview, NY. Production of the 700+ was canceled before it started (only a handful of pre-production prototypes were built)." He has even more info on the thread if you want to check it out.
That is way too intimidating for me to ever even wanna try. I’m about to try my first recap on an HK 330 C. This 900+ makes my 330 C look like a transistor radio.
Thanks for the information on this. Gonna save this for whenever i get enough motivation to re-cap my grandfather's. Fortunately it works. So all i really need to do is replace old caps. But that still looks incredibly complex.
Happy New Year Trev. Been around for a few years now. That thing is so old it could have been operated on several times. I had a pristine 730 last month. The lid had never been removed. Always a gamble. I'm finished with gear now. Moving on for 2025. I have saved enough gear for 10 lifetimes. Going back to motorcycles.
Wishing you a happy New Year Sir. Trevor is busy these days. You get your moneys worth with Quads (Parts parts parts) Damn, never seen this specimen, I don't think this made it to the States. Along with numbers provided on wires, I like how they are insulated. RCA Power transistors, 1st time seeing. Black widow Transistors (what I call them) Smoke Bombs. All your power outputs were per Mfg. specs.
What a strange thing to build. Seems almost a kit thing. Fine work and as always a great video. To me it would seem the value is in the CD4 and matrix decoders and if they could stand alone would be far better to just use just a modern multichannel amp.
Faultfinding on that monstrosity must be a nightmare. Will never complain again when I have to fix equipment again, not after I have seen what this nigtmare looks inside!!!! Another wild thing is that they use that slide switch to switch the outputs of the amp into bridge mode. Hopefully the contacts in that switch are beefier than what you find in most of those switches. The price of your repair must’ve been insane, and I guess the original price of that thing must make those silly $30000 pre-amps look cheap.
Trevor I think the reason those wires are numbered could be Harman Kardon may have assembled a few of their Heath Kits to rebadged it as a Harman Kardon could have been short on parts for the main run of these during line assemblies and just used the kit parts. Just a guess..
Crown Radio Corporation of Japan OEM'ed this receiver for H/K. I noticed the "Crown Japan" logo on the circuit boards. Their Shin-Shirasuna and Roland built receivers are of better quality and I am surprised that H/K used such a lower end, mediocre OEM like Crown Japan to build such an expensive receiver for them. You have more patience than me and If I were repairing that, I would just take my time with it. Whoever designed the layout and ease of serviceability, may it be H/K or Crown did a horrible job and you should charge Quad prices for the labor involved. All of those old Tosin electrolytics just gotta' go.
Thanks for the analysis! A bit off-topic, but I wanted to ask: I have a SafePal wallet with USDT, and I have the seed phrase. (alarm fetch churn bridge exercise tape speak race clerk couch crater letter). What's the best way to send them to Binance?
The 2SC485 transistor has a known high failure rate. They should be replaced on sight. I've always had success with KSC1845 as a replacement, it's a good low noise audio transistor with a gain range that's close. I tested all the transistors I pulled out and several were still good with a gain of around 400. About 10% of them had gain of around 200, none had failed completely.
Why not start with the power supply? If that is not putting out the correct voltages, then working on anything else first seems unproductive since you're going to have to get the correct voltages out of the power supply eventually. And it might be hard to test amplifier boards unless the power supply is working or you can use bench power supplies. Regardless, the power supply is going to have to be addressed sooner or later... I just can't understand why not sooner.
I always thought Quadraphonic stuff was a huge failer for its time. They dont even make Quadraphonic anymore that I know of. And from what I have seen there really is not alot of stuff out there in albums or good albums anyways. I only know of a few 70s stuff that I have found threw stores. And this stuff was not cheap back them for a mid person to even buy this stuff or the albums to as they were not cheap to than a normal album cost. Great work on the receiver tho that was alot of stuff in that one for sure wow. Not a fan of the face of it tho.
Some people (like me) prefer that the dial and meter lights are switched; others prefer that they stay on. Rewiring them so that they stay on is easy. I have done it a couple of times. If the selector switch has an unused pole, lights that stay on can be made to go off. I have done that twice so far and will eventually do it on more stuff.
You have the patients of a saint. I use to drool over this receiver when I was a kid at the Hi Fi shop. Back in the 70's we were too poor to afford such an expensive awesome thing. I remember the sound of the soft jazz they were playing at the store, nothing we ever had sounded so good. They were amazing receivers in their day.
After what you did to this receiver I'd say it's new resale value is at least $7,675.00. This one should be in a audio history museum. At least now you know how much you should charge for a restoration like this.
Looks like a service techs nightmare for sure. Kudos to you for even tackling this beast!
We don't often get to see a Quad adventure like this one; time patience, and experience won the day on this unit. I hope you and family had a Merry Christmas and best wishes for the New Year. Thank you for your time!
Wow! Two quad receiver videos in one morning. Even better, both of them are CD4 equipped. Thanks for this journey.
I didn't plan that, talk to Tony lol
That thing has the most components I’ve ever seen in my life - insane.
I have my grandfather's. I was gonna re-cap it. It still works and I lost motivation after counting them all. Lol
Trevor (greetings from the West Coast of Canada eh!) I thought you had patience and perseverance on some previous configurations...............but this 'takes the cake'!! I personally cannot see the rationale for the owner to want to have this unit fully restored and the fact that you stated at the outset that with the complexity of this model - your rate $$ would double! There must be some high nostalgic or personal reason to compel the owner to have you spend the time and his/hers $$$ to have this restoration completed. On your part - well done! This established a high-water mark as to your abilities (et al)!! It would be interesting as to the total hours you spent on this restoration and the $$. PS - you viewers who keep stating Trevor's Vids are too long - to you I say 'get lost'! Trevor. Thanks once again for a great year of vids. Health and Happiness to you and your extended family for 2025 (and well beyond) PPS. I wish you were located in 'my back yard' - I have a Marantz 2325 that could really use a 'Trevor Touch' restoration - Ha!
You're a braver man than me !
I think that must have been really expensive for HK to build and even more expensive to service when it needed any work just because there is so much crammed into the chassis !
eu diria que faltou mais organizaçao da harman kardon nessa unidade.
According to a former H/K technician on the QuardraphonicQuad forum:
"The 900+ (and the 100+ & 150+) was designed by H/K in the USA but custom manufactured exclusively for H/K by a company named "Crown Radio Company" in Japan."
@@rjonzun5828 That's interesting, I wonder if they actually made a profit on it ?
@@ian-c.01 The former tech, 4morhktech, on the thread: RCVR: Harman Kardon 900+ Quadraphonic Receiver at QuadraphonicQuad forum does not address the sales figures but does state the following in a reply:
"Yup, the 150+ came out in 1972 and was discontinued in late 1974. The 900+ came out in 1973 and was discontinued in late 1975. There was an overlap when both models were being produced. The 900+ did not really replace the 150+. All remaining H/K quad models were discontinued due to lack of software support in late 1975... insufficient numbers of recordings were produced by the major record labels to support 4-channel hardware sales. As a matter of fact, H/K was supposed to come out with another quad receiver, the 700+. The 700+ was first destined to be built in Puerto Rico, then that changed to Plainview, NY. Production of the 700+ was canceled before it started (only a handful of pre-production prototypes were built)."
He has even more info on the thread if you want to check it out.
That is way too intimidating for me to ever even wanna try. I’m about to try my first recap on an HK 330 C. This 900+ makes my 330 C look like a transistor radio.
Thanks for sharing 2024. Hope to see more projects soon.
Boy, that thing looks intimidating...the CD4 board looks like dense, miniature forest of components. 😲
Thank you, good one! Happy new year to you.. Keep up the good work, very enjoyable!!
Thanks for the information on this. Gonna save this for whenever i get enough motivation to re-cap my grandfather's. Fortunately it works. So all i really need to do is replace old caps. But that still looks incredibly complex.
Happy New Year Trev. Been around for a few years now. That thing is so old it could have been operated on several times. I had a pristine 730 last month. The lid had never been removed. Always a gamble. I'm finished with gear now. Moving on for 2025. I have saved enough gear for 10 lifetimes. Going back to motorcycles.
Wishing you a happy New Year Sir. Trevor is busy these days. You get your moneys worth with Quads (Parts parts parts) Damn, never seen this specimen, I don't think this made it to the States. Along with numbers provided on wires, I like how they are insulated. RCA Power transistors, 1st time seeing. Black widow Transistors (what I call them) Smoke Bombs. All your power outputs were per Mfg. specs.
What a strange thing to build. Seems almost a kit thing. Fine work and as always a great video. To me it would seem the value is in the CD4 and matrix decoders and if they could stand alone would be far better to just use just a modern multichannel amp.
One of these days ill get this treatment done on mine. Wish I still had the wood cabinet
Faultfinding on that monstrosity must be a nightmare. Will never complain again when I have to fix equipment again, not after I have seen what this nigtmare looks inside!!!! Another wild thing is that they use that slide switch to switch the outputs of the amp into bridge mode. Hopefully the contacts in that switch are beefier than what you find in most of those switches. The price of your repair must’ve been insane, and I guess the original price of that thing must make those silly $30000 pre-amps look cheap.
Trevor I think the reason those wires are numbered could be Harman Kardon may have assembled a few of their Heath Kits to rebadged it as a Harman Kardon could have been short on parts for the main run of these during line assemblies and just used the kit parts.
Just a guess..
Enjoyed thank you
What a parts beast!!! Good job! You mentioned it's 50 years old. What about the power supply main caps?
I have one of these. I guess I need to watch and learn as mine is not working.
Crown Radio Corporation of Japan OEM'ed this receiver for H/K. I noticed the "Crown Japan" logo on the circuit boards. Their Shin-Shirasuna and Roland built receivers are of better quality and I am surprised that H/K used such a lower end, mediocre OEM like Crown Japan to build such an expensive receiver for them. You have more patience than me and If I were repairing that, I would just take my time with it. Whoever designed the layout and ease of serviceability, may it be H/K or Crown did a horrible job and you should charge Quad prices for the labor involved. All of those old Tosin electrolytics just gotta' go.
Thanks for the analysis! A bit off-topic, but I wanted to ask: I have a SafePal wallet with USDT, and I have the seed phrase. (alarm fetch churn bridge exercise tape speak race clerk couch crater letter). What's the best way to send them to Binance?
Thanks. Not a clue bub, jog on...
So which part do you use/recommend when replacing the SC45s you so dislike? Is there a rationale for deleting these parts?
The 2SC485 transistor has a known high failure rate. They should be replaced on sight.
I've always had success with KSC1845 as a replacement, it's a good low noise audio transistor with a gain range that's close.
I tested all the transistors I pulled out and several were still good with a gain of around 400. About 10% of them had gain of around 200, none had failed completely.
Another episode of the Get Grey Hair Audio Conditioning Studio ✌️🐻
Why not start with the power supply? If that is not putting out the correct voltages, then working on anything else first seems unproductive since you're going to have to get the correct voltages out of the power supply eventually. And it might be hard to test amplifier boards unless the power supply is working or you can use bench power supplies. Regardless, the power supply is going to have to be addressed sooner or later... I just can't understand why not sooner.
I always thought Quadraphonic stuff was a huge failer for its time. They dont even make Quadraphonic anymore that I know of. And from what I have seen there really is not alot of stuff out there in albums or good albums anyways. I only know of a few 70s stuff that I have found threw stores. And this stuff was not cheap back them for a mid person to even buy this stuff or the albums to as they were not cheap to than a normal album cost. Great work on the receiver tho that was alot of stuff in that one for sure wow. Not a fan of the face of it tho.
Sucks that the lights on the radio meter are tied to an input, just like Sansui receivers... lame
Some people (like me) prefer that the dial and meter lights are switched; others prefer that they stay on.
Rewiring them so that they stay on is easy. I have done it a couple of times.
If the selector switch has an unused pole, lights that stay on can be made to go off.
I have done that twice so far and will eventually do it on more stuff.
only about 10 watts to run the lights in this thing
I have one that's broken
Those modification look like something that ham and egger Xray Tony would do "HI EVERYBODY"
I feel sorry for you. You must be a very negative sad person in real life. Always nothing but negative comments coming out of your pie hole.