- Harman Kardon 930 lost channel. Hoe to trouble shoot ? - 2 Updates
- World's Worst Soldering! - 7 Updates
- voltage doubler - 1 Update
| John-Del <ohger1s@gmail.com>: Oct 08 09:25AM -0700 > On Sunday, October 7, 2018 at 6:58:59 PM UTC-5, John-Del wrote: > > Sad to say, you're English is better than many native speakers... > Yup. the mistakes are mistakes, not laziness. You missed the sarkasm... > > I've changed many hundreds of outputs over the years, and have never seen one "open". > I have, but they are usually intermittent. Never saw one, but I did qualify my statement by saying that anything is possible. I've lived long enough to know that odd things happen. The only thing close is that I found a horiz output in an RCA CTC120 (or thereabouts) that was open. That was the first and only high power device I ever saw open. I still don't thing Steff has an open output. > > I can't speak for your particular HK, but most amplifiers (not all) use a common speaker protection relay so a shorted transistor on one side will prevent the speaker relay from engaging, rendering both sides mute. Your HK being an older vintage piece may be configured differently. > Actually none at all, there is no protection, no relay, delay or even output current limiting. Yikes. I remember a Hitachi receiver in the shop back in the early 80s that would destroy speakers whenever it wanted to. Play nice, short loud hum, speaker smoke. Turned out to be one of those weird Hitachi small signal transistors with the slanted top. Once every few days it would direct couple DC. |
| makolber@yahoo.com: Oct 08 09:27AM -0700 here is a tip, wire an outlet box with a duplex outlet and a switch. wire the outlet so the two outlets are in SERIES and in series with the switch.. Plug your unit into one outlet and plug a 100 Watt INCANDESCENT light into the other outlet. Use the switch to turn on/off the power. This makes it easy to turn OFF all the power when you are working on the unit. Also the bulb will limit the current if there is a fault. If the bulb glows brightly, there is still a fault and this will protect the new parts that you just put in. mark |
| Ralph Mowery <rmowery28146@earthlink.net>: Oct 08 11:25AM -0400 In article <5e64a5b5-e112-4777-9e8e-efafd34e5839@googlegroups.com>, peterwieck33@gmail.com says... > Anyone who uses 60/40 solder for other than plumbing and direct chassis connections on vintage radios deserves exactly what they get. Full Stop. > Peter Wieck > Melrose Park, PA You have it exectally backwards. I doubt if you will ever find any 37/73 solder. For two reasons. Number one is you now have a compound that is 110 % mix. Sort of impossiable to do. I will allow you a typo and say you ment 37/63. That would be a mix of 37% tin and 63% lead going by the normal way of stating the tin content first. The mix is 63 % tin and 37 % lead for the eutectic mix of solder. Over the years much solder is sold as 60 % tin and 40 % lead. Close enough for most electronics and very common. |
| John Robertson <spam@flippers.com>: Oct 08 08:26AM -0700 On 2018/10/08 1:08 AM, John Larkin wrote: >> It looks like an idiot tried to modify it. I have trouble imagining a >> legitimate company letting something that hacked out for sale. > It's Chinese. Perhaps it was a return from a customer who had a problem, then tried to fix it - botched it up, then sent it back to Amazon for a refund. The seller didn't bother to test or it simply was repacked in the Amazon warehouse for reshipment. Much like the people who buy clothes for a party then return them afterwards... John :-#(# |
| tabbypurr@gmail.com: Oct 08 08:33AM -0700 On Monday, 8 October 2018 03:44:54 UTC+1, Jeff Liebermann wrote: > The trick > to soldering is to use decent equipment, a clean tinned tip, and the > correct temperature. I tried a new soldering iron long ago that had a sawn off nail as a tip. The heating wire was wound onto this tip over an insulating sheet, so it wasn't replaceable. It soldered perfectly. I expect it would not have handled large joints, but I wasn't doing any at the time. A couple of years ago I tried soldering with nothing but a nail & a flame. Managed to produce good joints on pcbs, but the amount of time the nail stayed hot enough was very short, limiting what it could handle. Like many things, if you know what you're doing you can get all sorts of crap to work if necessary. NT |
| bitrex <user@example.net>: Oct 08 11:45AM -0400 On 10/08/2018 11:26 AM, John Robertson wrote: > Much like the people who buy clothes for a party then return them > afterwards... > John :-#(# I bought a guitar amp used many years ago where the previous owner had either accidentally or deliberately left inside the speaker enclosure a couple photos someone had taken of what appeared to be the previous owner, a heavy-set jolly-looking African American man eating dinner in his kitchen with what looked like a plate of ribs sitting on top of the amp. Sadly that amp was stolen from me a number of years ago along with the Polaroids that i'd left in it where I found them for some superstitious reason. Back into the "material continuum" |
| Stephen Wolstenholme <steve@easynn.com>: Oct 08 04:57PM +0100 My first job when I left school at 15 was on a TV production line. All the assembly work was done on a conveyer belt in about 30 minutes. I was at the test stage. Sort of plug it in and see if it works. Any faults were diagnosed by engineers and passed back to me. I had to negotiate with about 50 women to get anything fixed. If I picked the wrong women my survival that day was not guaranteed. It was a great place to get a girlfriend! -- http://www.npsnn.com |
| Tom Gardner <spamjunk@blueyonder.co.uk>: Oct 08 05:00PM +0100 On 07/10/18 17:08, Cursitor Doom wrote: > https://www.flickr.com/photos/128859641@N02/44247281105/in/dateposted- > public/ > As you can see, the "world's worst" tag was no exaggeration! If you want to learn how to do good soldering with "old" and "unsophisticated" equipment, see the Pace Basic Soldering Lessons. https://www.youtube.com/playlist?list=PL926EC0F1F93C1837 In contrast to most of the wittering talking heads and videos of printed pages(!) found on yootuub, those are excellent videos: - short, because production and distribution of the films was expensive - to the point, because they are short - good on theory of what needs to be done, and why - good practical demos of what happens when you get it right - and wrong The only major flaw is that it is difficult to suppress sniggering at the pronunciation of "solder". Of course CD won't see this message, because he's blocked me. His loss :) |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Oct 08 09:26AM -0700 On Monday, October 8, 2018 at 11:25:38 AM UTC-4, Ralph Mowery wrote: > The mix is 63 % tin and 37 % lead for the eutectic mix of solder. Over > the years much solder is sold as 60 % tin and 40 % lead. Close enough > for most electronics and very common. Yep - sorry. 37/63 lead-to-tin. Early AM post, and not quite awake. Peter Wieck Melrose Park, PA |
| Ralph Mowery <rmowery28146@earthlink.net>: Oct 08 11:17AM -0400 I am building a simple full wave voltage doubler to power some external circuits . I also want to use it at half voltage for lower voltage circuits. I am thinking that in this circuit I could take an output across just one of the capacitors as it seems to be a halfwave circuit with added components. Will this work or do need to put in a switch to switch out the other capacitor and or rectifier? https://www.daenotes.com/sites/default/files/article-images/full-wave- voltage-doubler.png |
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