Bottlehead Forum
Bottlehead Kits => S.E.X. Kit => Topic started by: sventyfour on November 04, 2009, 03:51:02 PM
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Hello all,
I've just purchased a second hand S.E.X. Kit that has already been assembled. It was working fine for a few months, but after a recent move I just recently had time to setup my stereo. I plugged everything in and flipped on the switch. The tubes glowed on, I heard a faint buzzing for ~5sec then it faded along with the tubes. I turned it off and there was a faint smell of melted plastic.
I'm a total newbie to the world of electronics and was hoping someone could help diagnose my situation. Where should I start? Should I go out and get a voltmeter first?
Thanks in advance,
Charles W.
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OK, the first thing to know is that you can always send it to Ed and get it fixed, if you have to. I say that not to get you to send it, but so you won't panic. :^) There is another option - if there is a Bottlehead near you, they might be willing to help. We're a pretty tight community.
Yes, the care and feeding of a home-built amp is likely to require a meter at some point, might as well be now. Cheap ones are good enough for most people and are widely available. Make sure you can measure up to 500 volts DC, and resistances.
Did you get the manual? There is a section on safety there which you MUST read and understand before you start poking your fingers in where there might be the aforementioned 500 volts. There is also a section on troubleshooting in the manual. And, if you are going to do any of your own troubleshooting, or if anyone here is going to be able to help you, you will have to become acquainted with the terminal identifications, also made clear in the manual. If you don't have it, either bug the seller or contact Eileen and get it.
OK, now we know a few things. The tubes glowed at first, so the transformer and tube heater power supply are working. The quick fade sounds like the fuse blew; you can check the fuse and may be able to tell visually if that happened. If not, you can measure the resistance when you have a meter and confirm that.
Assuming the fuse blew, and knowing that the tubes lit up, (and it worked for a few months), we're left with a guess that something in the high voltage areas shorted out. The burning smell is another clue. So you can at least turn it over and look closely at every part to see if there are charred remains of any dead parts. Learn to recognize resistors and capacitors, and look for bulging capacitors as well as burnt resistors.
Well, there's a starting point anyhow.
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Thanks Paul.
This is great info. Thanks!
I requested a manual from Eileen and am in the works of ordering a meter. So that should be a start. :)
As far as the fuse, it appears that is still intact, there is a slight curve to the wire, but still connected, I can test this once I get a meter? No poking around yet but I flipped it over just to peek around.
As for as charred remains, I cannot really tell for sure. I used my nose to try to source the smell, and i think it's coming from the top end near the transformers. This area:
http://vphill.com/photodatabase/public/viewphoto.php?ID=2006-01-01_069 (http://vphill.com/photodatabase/public/viewphoto.php?ID=2006-01-01_069)
Except on my S.E.X. Amp there are insulating sleeves over some of the leads of the black capacitors/resistors? And these plastic insulating sleeves look slightly puffy and possibly burnt.
Hopefully this helps a little more?
Thanks again.
Charles W.
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Yes, a multi-meter will test the fuse and many other things. Once you get the manual, you will find a section on testing resistances at various points, which will tell you a great deal.
The meter should also help you test those black diodes in the photo, which look to be the ones in the power supply for the tube heaters.
With the manual and the meter in hand, I would be very much surprised if you are not able to narrow the problem down a great deal. Spend some time with whatever instructions come with the meter; getting familiar with how the meter should behave when testing various things will be very helpful.
Honestly, troubleshooting a problem can be an excellent way to learn about this stuff!
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Charles,
I am in Knoxville TN. Are you around here? I, like many Bottleheads would show you how to troubleshoot your SEX amp. I would also do it for you, I'm a sad person I enjoy that, but I figure you want to learn and I will help you with that.
Grainger Morrison
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I would check that the black diode solder connections are secure. The lead wires on the diodes are thicker than normal and harder to solder well. That happened to me before. Especially after a move i would check most solder joints anyway. Use a chopstick and see if they are loose.
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We haven't asked if you have a soldering iron. That is the first thing you need. A meter is second. With those, and some solder, you are on your way.
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Charles,
Where are you from?
Alan
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I just received an email flyer from MCM Electronics this afternoon.
https://www.mcmelectronics.com/content/en-US/manufacturer/solder
It is a solder/soldering iron/soldering tools sale.
You could get everything you need from them. I have no affiliation except I have bought from them for 10+ years and they give good service.
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Wow, all of you guys are wonderful. This has got to be the friendliest and most helpful forum. I wasn't able to go home yesterday, and was pleasantly surprised to find so much good advice this morning!
I am from the Northern VA area about 20min outside of DC.
Grainger, although you're far, I have family in Knoxville, so perhaps some day :)
I haven't been had the chance to poke around anymore, but will definitely try the chopstick to see if that diode got loose and I'll try to snap a picture.
As far as a meter I heard fluke is good? any recommendations for an iron?
Thanks again!
Charles W.
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Charles, I'm off of Pellisippi Parkway at Westland. Literally!
You are invited to assistance and listening the next time you are visiting your family. PM me and I will send you my email and telephone number.
Edit:
The link I posted shows some really inexpensive soldering stations and meters. We all suggest soldering stations over a simple soldering pen. Most of us don't use solder that has lead in it. You can get both kinds at MCM.
I have a Fluke, but I am a retired EE. They are fine meters and just about all "autorange." That means you set it to AC or DC and it measures the voltage. You don't have to select a range of voltage. That is a worthwhile feature. Not to really disagree with Len, we really don't disagree much, there are Fluke meters for sale used on eBay for under $100. A meter is the most technical and useful tool you can have for electrical work. I'll take a look and suggest some model numbers if you are interested in spending as much as $60-$80 for a meter.
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As far as a meter I heard fluke is good? any recommendations for an iron?
Thanks again!
Charles W.
Fluke is great, but expensive. I have a bunch of meters, and last year I bought a Tenma from MCM as a knockaround meter (on sale). I find that I use it most! It's cheap and I think plenty accurate enough for this work. Unless you think you'll be taking this up as a hobby or you have lots of cash, I would go for something like that.
If others disagree please pipe in. I ain't proud.
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My 2 cents,
Spend more on a quality soldering station and less on the meter. George Anderson over at tubelab.com (http://www.tubelab.com) bought a bunch of the cheap Harbor Freight DMM's. He has a picture of the DMM's lined up along with his favorite DMM all showing the very similar voltages (http://www.tubelab.com/images/MeterUse/MeterTest.jpg).
I have a nice Hakko Station that I love. It heats quickly, stays hot, and has exchangeable tips. They have them at MCM that Grainger listed above. I am not a fan of some the cheaper stations like Weller, as they do not seem to hold up well. I have heard good things about the Xytronic units. George also has a nice getting started (http://www.tubelab.com/AssemblyManualSimpleSE/GettingStarted_SSE.htm) page that I have sent others. You might want to check it out, remember though it is just one mans opinion. your thoughts are what counts most.
Cheers, Alan
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Alan,
I have a Weller TCP (?) I have had since the 70s. I had to buy a new tip earlier this year, the first since it was new. All Weller's are not cheap. I expect that isn't what you meant to indicate but it is how it sounded to me.
As testament to Wellers, Terry DeWick's workshop is strewn with Wellers. It is all he uses. And he solders all day long 7 days a week. This is his site:
http://www.mcintoshaudio.com/dewick_repairs.htm
Check out the pictures. His work is beautiful. And the Yamaha T-1 he aligned for me was amazing. (I should say here I am just a fan, I am not affiliated with Terry.)
Possibly the cheapest Wellers are worse than the cheapest Temkas or Hakkos; possibly but I don't know. But a beginner might buy a $13 soldering station and buy a better one later.
By the way, how do you get a link to have different text than the address? I'm awful with computers.
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By the way, how do you get a link to have different text than the address? I'm awful with computers.
Hey Grainger,
Just hit "Quote" of his message, and you will see the HTML code.
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Alan,
I have a Weller TCP (?) I have had since the 70s. I had to buy a new tip earlier this year, the first since it was new. All Weller's are not cheap. I expect that isn't what you meant to indicate but it is how it sounded to me.
As testament to Wellers, Terry DeWick's workshop is strewn with Wellers. It is all he uses. And he solders all day long 7 days a week. This is his site:
http://www.mcintoshaudio.com/dewick_repairs.htm
Check out the pictures. His work is beautiful. And the Yamaha T-1 he aligned for me was amazing. (I should say here I am just a fan, I am not affiliated with Terry.)
Possibly the cheapest Wellers are worse than the cheapest Temkas or Hakkos. But a beginner might buy a $13 soldering station and buy a better one later.
By the way, how do you get a link to have different text than the address? I'm awful with computers.
Grainger,
Not implying they were cheap I just don't think they are as solid as they once used to be. I recently took some Classes at RIT, where the Wellers were not holding up very well and I based my statement on that experience.
As for the Hyperlink with text, I'll need to send you an email as I can not make it not work, So I cab not demonstrate the proper format. If you shoot me a PM with you email I'll fire off an example.
Please don't take offense, I was merely stating my opinion.
PS.. I love the link, thanks.
Cheers Alan
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Crap!
I discovered that early on and completely forgot it. Getting old is awful! Yup, I'm a bit behind you but degrading rapidly! Can't remember a thing these days!
Alan, PM sent.