I am so glad you took the time to explain about the 2 separate voltages. The reason is because I saw the bridge in the middle of the mainboard early on, and I thought exactly to myself, "Wow, what a strange place to put that!," and then I also saw how far away from the power cord inlet that it is. To me, very strange at the time. After your explanation which easily helped me understand straight away, now, not so strange! Thanks man.
I had one of these but I don't remember if it was this model! But boy I loved it and I had it for over ten years and never failed me! I now have an Onkyo and it's doing pretty good so far! I need to buy an fan to put on top to cool the board while running because it does put out some temps!
I've worked on more of these than I can count/remember and you nailed/mentioned just about every problem I've run across with this model. Mainly solder connections. Kind of a "thing" with most manufacturers of this vintage, but these were the last of the "rack system" boom and apparently they sold like cucumbers in a womens prison! One major issue is some of those output packs go bad from bad solder joints--and they're VERY spendy to replace. This model looked to use the same module for the mains as well as the center/surround. Not all were like that, but if on this one the main one is blown you can swap the modules and still have a decent two channel amp........
More equipment likely zapped by heat. Assuming you had some equipment with components like those regulators that ran hot and you wanted to future proof it and avoid repairs down the road, would it be possible to add heat sinks to the components that are running hot?
Yep, saw that ... it was the "as of this one" solder joint that didn't seem to take the solder properly ... there's a gap all around that joint ... you can't just dab the soldering iron and hope for the best, else you'll be back to square one ... solder & joints need proper heat to make a decent connection ...
Hello sir. Your vieo are both enterteining and educational. I've recently bought an hifi from the same brand, with the amplifier module SA-EH60, but there's a problem: one speaker output has an issue, I need to stretch the cable close to the output in order to make it work. What should I investigate to solve it, in your opinion. Thanks in advance
If the customer would spring for it, it would have been interesting to try to fix the remote with some of that conductive silver paint or similar product.
There is no money in this repair. Like all of them. A used remote could be had for about 5 bucks. I fix many remotes but that one was too far gone to even consider. Another reason to walk away is because even if i did get it working I would be married to it when it broke again and break again it would... Very soon.
I have a pair of big polks in my media room. Sorry don't know the model off hand but they have big 12" side firing subs and 2 6" drivers and a tweeter. They are piano black and stand about 4 feet high by about a foot and half deep. Cost a small fortune when i got them about 20 years ago. Sound fantastic.
That is not why it bridged. it was because i was impatient and did not wait for my iron to get to operating temperature. Why waste flux. It is expensive. I make 20 bucks on a repair like this so why would i waste 5 bucks on flux to do it. And no I can't charge people more. I get stuff in and am told i can go to 20 and if more just drop at recycle center. That fancy flux that comes in the syringe costs about 10 bucks at the local electronics shop (which isn't that local as it is a 45 mile drive round trip) I have an old bottle of mg flux that there is a tiny bit left but I reserve that for the jobs that really need it. This wasn't one of them. It is reserved for SMD work basically.
Idk why Technics stopped making these class H amps/ receivers. These were great. The class H allows full power amps for a lower price.I think you get the same output regardless of how much channels are being used. Newer av amps says 100 watts but when you look closely it with 2 channels driven so the more channels you use the less output you get.
I have a photographic memory. I remember exactly where I put them and even have a system. They go on different places. Never lose any screws. Any you see lying around are from things that came apart and never went back together. (parts donors usually).
@@12voltvids You lay it on a worn wooden surface and turn it around and rub it. of course there will be small scratches and marks! Not what I want to see if I deliver my nice things for repair!!
@@ford1546 nothing cosmetic was in contact with the clean wood surface when it was moved. Also this is a garage amp. It is already scuffed and scratched.
@@12voltvids I know. But it is not enough. If you apply a layer of flux, it is much easier to solder and it will be nicer. Anyone who solder ic. or where there are many solder points close together does so. the downside is that you have to wash more afterwards.
@@ford1546 There is a big difference between soldering down a SMD ic with .5mm pin spacing and soldering thru hole components. For thru hole there is more than enough flux in the solder. If you feel you need to use flux on thru hole then you aren't doing it right.
@@12voltvids Ok. I use extra flux and sometimes gives better results. if you solder on old solder then ekstea flux may be necessary. you had some points where you struggled a bit and had to suck away the solder. with extra flux you would not have needed it. My personal experience with isopropanol alcohol is not so good. you spread flux around the card instead of removing it!
They only used to be serviceable because governments forced manufactures to make products repairable and stock parts. People pressured governments to deregulate which they did. Now they only have to replace anything that breaks in warranty period. This resulted in lower costs because stocking replacement parts for 10 years costs a ton of money.
Couldn't sleep so viewed at 5 AM....well worth the time....now going to see if I can fall asleep with a bit more education. Thanks Dave JwgK
Love these Technics class H amps. The sound great when all tuned up. Thanks for the vid.
Excellent repair and very informative .thank you
Gracias desde Argentina!, ahora me voy a animar a desarmarlo todo!
Thank you for posting, you are my favorite channel.
Yes nice watch as well looks well looked after
I am so glad you took the time to explain about the 2 separate voltages. The reason is because I saw the bridge in the middle of the mainboard early on, and I thought exactly to myself, "Wow, what a strange place to put that!," and then I also saw how far away from the power cord inlet that it is. To me, very strange at the time. After your explanation which easily helped me understand straight away, now, not so strange! Thanks man.
On a side note, I believe the 1541 Commodore floppy disk drive also has 2 bridges and the same idea going on.
I had one of these but I don't remember if it was this model! But boy I loved it and I had it for over ten years and never failed me! I now have an Onkyo and it's doing pretty good so far! I need to buy an fan to put on top to cool the board while running because it does put out some temps!
I've worked on more of these than I can count/remember and you nailed/mentioned just about every problem I've run across with this model. Mainly solder connections. Kind of a "thing" with most manufacturers of this vintage, but these were the last of the "rack system" boom and apparently they sold like cucumbers in a womens prison! One major issue is some of those output packs go bad from bad solder joints--and they're VERY spendy to replace. This model looked to use the same module for the mains as well as the center/surround. Not all were like that, but if on this one the main one is blown you can swap the modules and still have a decent two channel amp........
Nice repair! The Benchmark AHB2 shows what a Class H amplifier can really do. Certainly nothing to whine about.
THANK YOU !!! WORKED !!!
More equipment likely zapped by heat. Assuming you had some equipment with components like those regulators that ran hot and you wanted to future proof it and avoid repairs down the road, would it be possible to add heat sinks to the components that are running hot?
One of those speaker terminals still looked cracked when you finished.
Yep, saw that ... it was the "as of this one" solder joint that didn't seem to take the solder properly ... there's a gap all around that joint ... you can't just dab the soldering iron and hope for the best, else you'll be back to square one ... solder & joints need proper heat to make a decent connection ...
Love your videos. I'm also interested in watches. How long have you had your casio waveceptor? Looks like it's held up very well
At least 20 years now.
What type/ size of solder do you recommend for this type of repair? Love your vids and commentary.
cat was not a fan off those speakers Dave but still love the cats from time to time love you work
does a JIS screw have a * head on it?
I noticed some flux on the board but haven't ever seen you use it. Do you use flux and if so, when / what for?
What wattage of an iron do you use, when you change// install components on a board .
I believe it is 60 watts.
70 watt @ 800 F works for me for most PCB's.
Hello sir. Your vieo are both enterteining and educational. I've recently bought an hifi from the same brand, with the amplifier module SA-EH60, but there's a problem: one speaker output has an issue, I need to stretch the cable close to the output in order to make it work. What should I investigate to solve it, in your opinion. Thanks in advance
If the customer would spring for it, it would have been interesting to try to fix the remote with some of that conductive silver paint or similar product.
There is no money in this repair. Like all of them. A used remote could be had for about 5 bucks. I fix many remotes but that one was too far gone to even consider. Another reason to walk away is because even if i did get it working I would be married to it when it broke again and break again it would... Very soon.
Polk audio is my favorite. Bad kitty lol!
I have a pair of big polks in my media room. Sorry don't know the model off hand but they have big 12" side firing subs and 2 6" drivers and a tweeter. They are piano black and stand about 4 feet high by about a foot and half deep. Cost a small fortune when i got them about 20 years ago. Sound fantastic.
I've got an Onkyo 7.1 receiver with 2 bad output transistors in one channel.... And no access cover underneath.... Grrrrrrr.
Sounds like the NAD Power Envelope system with two commutating power rails.
That was NAD trademark. Same thing.
You could use some flux, that way you avoid those solder bridges quite easily.
That is not why it bridged. it was because i was impatient and did not wait for my iron to get to operating temperature. Why waste flux. It is expensive. I make 20 bucks on a repair like this so why would i waste 5 bucks on flux to do it. And no I can't charge people more. I get stuff in and am told i can go to 20 and if more just drop at recycle center. That fancy flux that comes in the syringe costs about 10 bucks at the local electronics shop (which isn't that local as it is a 45 mile drive round trip)
I have an old bottle of mg flux that there is a tiny bit left but I reserve that for the jobs that really need it. This wasn't one of them. It is reserved for SMD work basically.
Do you see any reason why an amplifier can't be left 24/7 on on please
It can and many are.
@@12voltvids thank-you
i have a similar model which the d2037 and b1357 is heating like fire but transistors are okey. what should i do next,
Sounds like too much bias
came in direct from power caps with a 6.8 ohms resistor and the resistors are also fine a bit roasted, i replaced them. still not working@@12voltvids
baculite tolerates little heat before it becomes discolored.
Hmm class H, supply voltage variation depending on output requirement.
Less wasted power in the outputs.
Not something i've seen before.
Crown poweramps and other PA poweramp manufacturers use these types of designs.
Idk why Technics stopped making these class H amps/ receivers. These were great. The class H allows full power amps for a lower price.I think you get the same output regardless of how much channels are being used. Newer av amps says 100 watts but when you look closely it with 2 channels driven so the more channels you use the less output you get.
I use a NILES cooling fan under my amp to keep my TECHNICS cool.
The fan on this comes on as the power increases. That way you don't hear an annoying fan at low levels.
everytime I saw you throw those screws arbitrary on the work bench, I am so worry you will miss some of them and unable to put them all back .....
I have a photographic memory. I remember exactly where I put them and even have a system. They go on different places. Never lose any screws. Any you see lying around are from things that came apart and never went back together. (parts donors usually).
You need to handle what you are repairing much better. You have to put it on something soft!
Nothing to scratch here. The face was off it remember.
@@12voltvids You lay it on a worn wooden surface and turn it around and rub it. of course there will be small scratches and marks!
Not what I want to see if I deliver my nice things for repair!!
@@ford1546 nothing cosmetic was in contact with the clean wood surface when it was moved. Also this is a garage amp. It is already scuffed and scratched.
a tip. use flux and it will be much easier
There is flux in the solder. Rosin core.
@@12voltvids I know. But it is not enough. If you apply a layer of flux, it is much easier to solder and it will be nicer. Anyone who solder ic. or where there are many solder points close together does so. the downside is that you have to wash more afterwards.
@@ford1546
There is a big difference between soldering down a SMD ic with .5mm pin spacing and soldering thru hole components. For thru hole there is more than enough flux in the solder.
If you feel you need to use flux on thru hole then you aren't doing it right.
@@12voltvids Ok. I use extra flux and sometimes gives better results. if you solder on old solder then ekstea flux may be necessary.
you had some points where you struggled a bit and had to suck away the solder. with extra flux you would not have needed it.
My personal experience with isopropanol alcohol is not so good. you spread flux around the card instead of removing it!
@@ford1546 no, that was because my iron was not up to proper operating temperature. When it is cold it is harder to work with.
Doesn't lead sold hold up better
Dave try Nature's Miracle it gets rid of urine using bacteria
you need a cat/apult
Back in the day they were building servisable electronics, this days these moter f... are making them single use...
They only used to be serviceable because governments forced manufactures to make products repairable and stock parts. People pressured governments to deregulate which they did. Now they only have to replace anything that breaks in warranty period. This resulted in lower costs because stocking replacement parts for 10 years costs a ton of money.
When fixing motorcycles, we would flatten a phillips with a grinder or file...voila Bodge JIS. If you didn't, have fun removing them next time.
I always liked technics big stereos years ago
I have one of their "new class A" units with the parametric eq. Very snazzy!
I have the suv9 which was one of their best.
@@12voltvids MANN YOU HAVE EVERYTHING DONT YA??
Had to verify the model: SA-GX500