Nice Job Tony, and yes; I am one of those who enjoys all the soldering. I also like that you're honest enough not to edit out the little mistakes - Shows you're just as fallible as the rest of us mere mortals.
Another great video = Thank you! For power supply caps that are close to a heat source... An option might be to leave their pins long, cover the pins with heat shrink and move the cap away from the heat source, a bit, when the board has room to do such. Or, mount the cap turned on its side. I know the rule is to have the cap close to the component it serves, but keeping it cool at a distance might be better than hot up close. Just thinking...
I bought some of those 125c blue nichicon caps when I fixed some powered speakers for a guy last year. That cap lived next to some power resistors and got baked, BAD.
@@dhpbear2 most important if soldering first then cutting the leads can stress the solder joint and mirco fracture the leads of the board or the trace itself. And like Tony said soldering after cutting covers open copper lead ends. If I need to repair it for a costumer and don't want to pay me enough. Ok then I'm a little racing car and repair it test it and that's it. If I'm restoring it the right way and for the hobby I'm paying attention. 😉
Tony at 42:02 you placed the 47uf 50v at the original place if heat can be an issue why didn't you solder them underneath the board there was plenty of space and the board isolate the heat to the electrolyte. 😁 Anyway nice videos I'm more into tubeamps but this is fun too, I'll learn a lot.
Always a pleasure. I would say that if you did not enjoy this work , we would certainly take note of it from your actions. That said, now you know why we watch. Thanks.
The LCR meter will show lower capacitance the higher the test frequency you use. If you select 120 Hz I think you will get closer to the nominal value.
I actually put a note in the video stating that I was testing at 120Hz. You are correct, however. Raising the test frequency will cause the capacitance to read even lower, especially with electrolytics. Even at that frequency (120Hz), it still reads the capacitance as being lower, when compared to the Sencore LC53. All of these types of LCR meters seem to do this.
@@xraytonyb ah, I see. I think it’s because the non LCR meters measure the capacitance by measuring the charge time curve using DC. In comparison to LCR meters that measure the current and phase with AC. That is probably why there is a difference between the two types, at least as far as I understand it. Seems to me like AC measurement would be more accurate since that is how it is used in the circuit.
I know that some of your video are kind of stretched out and may seem long. I for one do not mind so much, it is reassuring to watch you struggle to do the actual work ,de soldering and fitting all the fiddey bits makes me feel less like a klutz and to keep it up it takes what it takes.
Love your videos Tony. Always expanads my knowledge of vintage electronics. Harman Kardon made great amps. Thank you so much. Jonny Seven from England.
One of the best electronic learning channel which teaching us both in theory and hands on techniques. Thank you very much for sharing your knowledge and experience.
Greetings: When replacing parts, I prefer to solder before clipping leads as I am less likely to fail to solder some, at the expense of having leads in the way (get creative at lead bending).
HK is very good at silkscreening their boards, but then I think their boards are sourced out to ELNA. I can't remember the last time I've seen an error
Any particular reason why you didn't measure for leakage in the large electrolytic capacitors? I wonder what you would have seen using one of these: ( ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-LhovRIM5xAo.html )
I tested it on the Sencore LC 53. They were fine. It is also important to check ESR/dissipation factor. Leakage testers will not show those factors. Leakage and ESR/DF are equally important when testing these types of electrolytic caps. Thanks for the comment! BTW, the original Carlson leakage tester doesn't work very well for electrolytics, but as I understand, his new version (came out after the one you referenced) can apparently test them ;)
The flashing LED at startup indicates it is going through its startup routine, but I hear "boom" on the speakers when it stops flashing. I do not have it on my other amplifiers. Is it a failure or just a feature?
I'd just like to echo the thanks from other viewers. I'm enjoying your restoration and testing of this amplifier very much. By the way, I see the use of Cone Beam CT X-ray equipment at work. When I started out everything was 2D on Film. I take my hat off to you working in the x-ray equipment field, it's been a time of rapid change in the last 15 years.
I'm watching all your videos, and will watch them repeatedly as I have an HK6600; a great amplifier with no issues right now--but for the future, I'll know at least a bit of what I'll be getting into. There's no one anywhere near where I am who can do what you do.
I think you get a distortion character easier on the ear, more into class A, cos it's more even harmonics...that's what the class A guys say anyway... With the smoothing caps, no one ever seems to worry about checking the ripple current...some new caps seem awfully small, I know construction and materials are more efficient now, but I wonder whether sometimes the size reduction is partly due to lower ripple current rating...
So uh, yeah, I got an opinion for ya.....I LOVE what you do in these videos!!!! :) So, on those large electrolytics, I skipped ahead a bit and may have missed something but I don't think you mentioned it? There's a simple touchy/feely/listen test you can do with those big cans-even before checking with a meter. Simply remove em and shake the snot out of em. If they rattle (and yes I've found several that did) they're paper weights. I don't care what they measure. No rattle cans go back into my repair projects!
Just for future reference the Kemet ALC10 series caps come in the 22mm 4 pin type. I can't link it here but if you search 10kuf, 63v 4 pin caps it's the only one that turns up. I think UCC makes some too but apparently Mouser doesn't have any in stock. I've used Kemets for main filters in a bunch of projects and have had great results.
I enjoy ALL of your approaches. Sometimes, while the theoretical and schematic parts can be dry, I have the choice to step back for awhile and come back and come back I do! You can't be all things to all people! LOL
Just wondering if the Transistors required for a repair are no longer available is it alright to use NPN and PNP power transistor modules to replace the Power Transistors
