I guess the Q.C. person was looking at something else when this unit went by on the line. If he/she missed this one, there were obviously more. Thank you for the troubleshooting techniques, and the workmanship. This unit is happy again and will live on!
When I was a senior in High School in the late 80s, I bought a set of Harmon Kardon stereo equipment at an auction. Amplifier, pre-amp, and tuner, with stand and giant speakers, for $95. The amp had an issue where one channel was very quiet unless I cranked the volume, then it "popped" and was normal. The speakers were also blown and corroded, but they worked well enough. I added a Technics cassette deck, and loved it. When I moved nearly 10 years later half way across the USA, I left the electronics in storage with my parents. Five years later, they moved out of the old farm house onto a new house on the property, and sadly, the squirrels and raccoons moved in to the farm house and ruined a lot of things, including my stereo setup. I wish I knew then what I truly had.
Great troubleshooting. Lot of times it can be something really simple like that. I'd say 40-50% of time it's a loose connection or failed solder connection I run across. Cheers! 🍻 Great to watch a master in action! -Al
That iron tip looks like its been through a couple of wars, used as scrap in a IUD then recovered for use! lol. If you can't make her wet, then you might be doing something wrong, haha :) Excellent troubleshooting and thanks for the information! Your videos are excellent and have helped me learn some new tricks and tips! Thank you much!
This must have come out of the Shin-Shirasuna factory. I had a boombox built by them in 1985 that didn't make it one year without solder joint problems.
That unit was sabotaged by a POW. It's good to see it will be able to utilize its full potential after the TLC you gave it. I would have given the PCB's a little clean too, as a finishing touch. Thanks for the ongoing stream of videos, I learn a lot from them.
Acctually I got an old tube radio (1963) in yesterday with left channel dead. Turned out it had the same type of fault. The cable from the volume pot to the capacitor in the output stage wasn't soldered to the capacitor, it was just touching it. But now after almost 60 years it's finally been soldered.
Supprising that the soldering was so sloppy and it manage to work at all!. The little transistors with one lead just sitting there without solder lol. Lack of inspection, but it has lasted some time. i do like the block power amplifiers, but i'm no fan of the transistor sockets.
Dont know where to post this somewhat related question. I have an ARCAM AVR-400 receiver. Using HDMI connections whenever the audio kicks in the sound goes off and the panel display says "headphone bypass" . The video is still displayed, just no sound. It doesnt matter what the source is DVD, PC, console game, etc. Ive googled for the last 6 months and gotten nothing but how to connect headphones! Thought Id give it a shot here.
Did Harmon Kardon produce any kits? That does not seem to be the level of quality I have seen with them. Love what you did here, it is the same that I do. Spend time on a good visual inspection, use all the senses, touch, smell, bump, thump, move, wiggle. Saves lots of time before hooking up the scope or test equipment.
Hi I have the same amp I just bought and it started doing some crackling noise on one channel both A B speakers , checked the DC off set and one side is over 115mn .... this unit was suppose to been re capped ... where can I look first ?
Actually Harman Kardon is a US based audio company which now owns a long list of Hi-Fi brands including former glory as AKG and Studer (Revox). Guess saving on manufacturing and quality control did indeed paid off in the end ...
Unfortunately, this problem is to be expected, because the whole testing process is ALL wrong. For a batch of say 1000 appliances, only 100 out of the whole batch would be thoroughly tested, for example. If they passed the test, the whole batch would be signed off as OK. This means that the remaining 900 could be either faulty, or don't work at all. I was a QA Inspector many years ago, so I know the testing process 1st hand.
I have a Proton AP=1000 pre amp that needs work. Left and right channel cut out until you move the input selector to a sweet spot. You want to fix for me?
The speakers make a big difference. I am running a pair of psb mites on the akai. These are great little Canadian speakers. Currently the test speakers I use on repair amps are just a pair of JVC from a mini system. I'll probably get around to putting some polk bookshelf speakers up for the test speakers some day.
Well i don't think that really matters now does it. Both channels work and that is all that matters. If the owner wants me to investigate why one of the LEDs isn't lit, he can pay for it. I sure as hell wouldn't care if a light was out
The word you fumbled for is *jumpers*. Virtually no audio company used patch-cords to connect pre-out to main-in. Horseshoe-shaped metal jumpers; replacements can be easily made from aluminum antenna-grounding wire and needle-nose pliers. We often see amplifiers missing the original jumpers, presumably because some type of equalizer or other signal processing device (a Bose 901 eq perhaps) was used inbetween the preamp and poweramp.....or sometimes the unit was used strictly as a preamp because of a defective power amp section. BTW, there are three or four different spacings commonly used between the pre/main RCA jacks; I know this because I've had to make replacement for hundreds of missing jumpers.
I was referring to the fact that i had to use patch cords to connect the pre out to the main in because the jumpers were missing. The guy that ownes this uses it with an equalizer. Another piece of equipment that won't get within 100m of my system. My system is so basic. It has a power switch, input selector switch and volume control.
I guess the Q.C. person was looking at something else when this unit went by on the line. If he/she missed this one, there were obviously more. Thank you for the troubleshooting techniques, and the workmanship. This unit is happy again and will live on!
It's sobering to think that whoever assembled this unit originally could be long dead by now. Sometimes our mistakes outlive us...
They very well could be
When I was a senior in High School in the late 80s, I bought a set of Harmon Kardon stereo equipment at an auction. Amplifier, pre-amp, and tuner, with stand and giant speakers, for $95. The amp had an issue where one channel was very quiet unless I cranked the volume, then it "popped" and was normal. The speakers were also blown and corroded, but they worked well enough. I added a Technics cassette deck, and loved it.
When I moved nearly 10 years later half way across the USA, I left the electronics in storage with my parents. Five years later, they moved out of the old farm house onto a new house on the property, and sadly, the squirrels and raccoons moved in to the farm house and ruined a lot of things, including my stereo setup.
I wish I knew then what I truly had.
This is one of the best sounding amplifiers ever!
Great troubleshooting. Lot of times it can be something really simple like that.
I'd say 40-50% of time it's a loose connection or failed solder connection I run across.
Cheers! 🍻 Great to watch a master in action! -Al
U have the best stereo repair Vids and great information !!
That iron tip looks like its been through a couple of wars, used as scrap in a IUD then recovered for use! lol. If you can't make her wet, then you might be doing something wrong, haha :)
Excellent troubleshooting and thanks for the information! Your videos are excellent and have helped me learn some new tricks and tips! Thank you much!
I had one of these. Bought in the late seventies. It developed the same problems after about ten years of use.
Wow that pioneer, incredible.
Bravo, great diagnosis and subsequent fix
Thanks
This must have come out of the Shin-Shirasuna factory. I had a boombox built by them in 1985 that didn't make it one year without solder joint problems.
AMAZING! Great Repair!
that is a nice one to work on.
That unit was sabotaged by a POW. It's good to see it will be able to utilize its full potential after the TLC you gave it. I would have given the PCB's a little clean too, as a finishing touch. Thanks for the ongoing stream of videos, I learn a lot from them.
Just commenting to say cool! I am eating a store pizza i just made and this video content hits the spot. At just 2 minutes in now! :)
Acctually I got an old tube radio (1963) in yesterday with left channel dead.
Turned out it had the same type of fault.
The cable from the volume pot to the capacitor in the output stage wasn't
soldered to the capacitor, it was just touching it.
But now after almost 60 years it's finally been soldered.
Supprising that the soldering was so sloppy and it manage to work at all!.
The little transistors with one lead just sitting there without solder lol.
Lack of inspection, but it has lasted some time.
i do like the block power amplifiers, but i'm no fan of the transistor sockets.
What a lovely amp.
Sounds great too
Something up with Harmon kardon..I had a bad solder joint on a transistor..causing it to randomly shut off.
Dont know where to post this somewhat related question. I have an ARCAM AVR-400 receiver. Using HDMI connections whenever the audio kicks in the sound goes off and the panel display says "headphone bypass" . The video is still displayed, just no sound. It doesnt matter what the source is DVD, PC, console game, etc. Ive googled for the last 6 months and gotten nothing but how to connect headphones! Thought Id give it a shot here.
Nice job. I had a car radio cassette that had a loose capacitor. It was an easy fix.
Loose connections number 1 fault.
@@12voltvids exactly
I found a gladding mark 200a quadraphonic at a thrift store today..one channel is dead.. so little Info on it.
Did Harmon Kardon produce any kits? That does not seem to be the level of quality I have seen with them.
Love what you did here, it is the same that I do. Spend time on a good visual inspection, use all the senses, touch, smell, bump, thump, move, wiggle. Saves lots of time before hooking up the scope or test equipment.
No kits.
Hi I have the same amp I just bought and it started doing some crackling noise on one channel both A B speakers , checked the DC off set and one side is over 115mn ....
this unit was suppose to been re capped ... where can I look first ?
Actually Harman Kardon is a US based audio company which now owns a long list of Hi-Fi brands including former glory as AKG and Studer (Revox). Guess saving on manufacturing and quality control did indeed paid off in the end ...
Sound united
That akai sound better then the HK
when you touch a live voltage part of a circuit, do you keep the other hand in your pocket?
I keep it away from anything that can conduct. If I am standing yes one hand in pocket
Unfortunately, this problem is to be expected, because the whole testing process is ALL wrong. For a batch of say 1000 appliances, only 100 out of the whole batch would be thoroughly tested, for example. If they passed the test, the whole batch would be signed off as OK. This means that the remaining 900 could be either faulty, or don't work at all. I was a QA Inspector many years ago, so I know the testing process 1st hand.
1 out of 10 sounds about right.
I have a Proton AP=1000 pre amp that needs work. Left and right channel cut out until you move the input selector to a sweet spot. You want to fix for me?
Contact by email
Just wondered if you leave deck off for 24 hours will display still work like in this video?
I left it off for about 6 hours before plugging it in to shoot this segment.
@@12voltvids Cool! Good to know!
Very cool, like vintage stuff
So do I.
What Akai do you have there?
I can hear a lot more definition on the Akai, especially in the highs. You can't really make out the cymbals on that HK.
The speakers make a big difference. I am running a pair of psb mites on the akai. These are great little Canadian speakers. Currently the test speakers I use on repair amps are just a pair of JVC from a mini system. I'll probably get around to putting some polk bookshelf speakers up for the test speakers some day.
Nice repair, do you sell them ?
This is a customers unit.
@ 24:37 only one of the power leds seems to be lit, while @ 1:40 both of them are lit
Well i don't think that really matters now does it. Both channels work and that is all that matters. If the owner wants me to investigate why one of the LEDs isn't lit, he can pay for it. I sure as hell wouldn't care if a light was out
The word you fumbled for is *jumpers*. Virtually no audio company used patch-cords to connect pre-out to main-in. Horseshoe-shaped metal jumpers; replacements can be easily made from aluminum antenna-grounding wire and needle-nose pliers. We often see amplifiers missing the original jumpers, presumably because some type of equalizer or other signal processing device (a Bose 901 eq perhaps) was used inbetween the preamp and poweramp.....or sometimes the unit was used strictly as a preamp because of a defective power amp section. BTW, there are three or four different spacings commonly used between the pre/main RCA jacks; I know this because I've had to make replacement for hundreds of missing jumpers.
I was referring to the fact that i had to use patch cords to connect the pre out to the main in because the jumpers were missing. The guy that ownes this uses it with an equalizer. Another piece of equipment that won't get within 100m of my system. My system is so basic. It has a power switch, input selector switch and volume control.
bad quality control when it left the factory with that wire not soldered on the board
this thing to spoil inner parts instead of simply putting a label is not so appealing. intersting video anyway
They had very poor quality control. That why I always side step the brand.