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Post by resonatadog on Oct 29, 2023 7:58:21 GMT
Hello, my Blues jr started making bad noises, Ii Traced it to a bad/loose socket after swapping tubes and changing their orientation. I noticed two of the pin solder points were discoloured (light brown) I tryed adding more solder to the points. Sadly ‘‘this resulted in the the socket not firing the tube at all, thought the amp still works. But now I’ve taken all the tubes out and I’m planning to change the socket. Can you assure me or advise me against it? Any advice appreciated (edit) after initial classic valve misplaced noises I swapped valves then got the bright orange over heating of the valve so thinking their unmatched i switched back to the harma upgrade valves and kept the amp under observation so putting the valve guard back on after a couple of sessions of things working seemingly well it stared with the loud shufferling noises again. After that the rest is as I said. As I say any help. Yes I know take it to some one who knows what’s what. Basically want to know is replacing the socket a more or less straight forward job. Thanks for your time
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Post by resonatadog on Oct 29, 2023 17:49:51 GMT
Hope this post is coherent
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Post by pete1951 on Oct 29, 2023 18:09:51 GMT
I think this is a job for someone more experienced than you sound. I have made a few valve amps but have not repaired any for other people ( other than replacing valves) as you can kill someone with the voltage and am also not a proper electrical engineer.
Blues juniors are a good small amp but they are made as cheaply as possible, there are often overheating problems and there are people around who will rewire them ( the ‘ribbon’ to the valves often needs replacing with proper wire)
Someone on the forum may feel confident ‘talking’ you through it, but remember 400 volts up one arm across your heart and down the other one to earth can seriously affect your heath!
Pete
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Post by mitchfit on Oct 29, 2023 18:47:44 GMT
SHAMELESSLY STOLEN FROM: www.asc.ohio-state.edu/physics/p616/safety/fatal_current.htmlIt's The Current That Kills Offhand it would seem that a shock of 10,000 volts would be more deadly than 100 volts. But this is not so! Individuals have been electrocuted by appliances using ordinary house currents of 110 volts and by electrical apparatus in industry using as little as 42 volts direct current. The real measure of shock's intensity lies in the amount of current (amperes) forced though the body, and not the voltage. Any electrical device used on a house wiring circuit can, under certain conditions, transmit a fatal current. While any amount of current over 10 milliamps (0.01 amp) is capable of producing painful to severe shock, currents between 100 and 200 mA (0.1 to 0.2 amp) are lethal. Currents above 200 milliamps (0.2 amp), while producing severe burns and unconsciousness, do not usually cause death if the victim is given immediate attention. Resuscitation, consisting of artificial respiration, will usually revive the victim. THIS IS HOW SOME SURVIVE A MEGA-VOLT LIGHTNING STRIKE, ALL VOLTS WITH LITTLE AMPS-stolen from WIKI: Roy Cleveland Sullivan (February 7, 1912 – September 28, 1983) was an American park ranger in Shenandoah National Park in Virginia. Between 1942 and 1977, Sullivan was claimed to have been struck by lightning on seven occasions, surviving all of them. For this reason, he gained the nicknames "Human Lightning Conductor" and "Human Lightning Rod". Sullivan is recognized by Guinness World Records as the person struck by lightning more recorded times than any other human being.[3][4] mitchfit |
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Post by mitchfit on Oct 29, 2023 19:09:11 GMT
P.S.
caps kill.
mitchfit
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Post by Pickers Ditch on Oct 29, 2023 19:16:23 GMT
The bottom line is:
DON'T DO IT!
TAKE IT TO A FULLY QUALIFIED AMP TECHNICIAN!
You may save a few quid but you could end up killing yourself or, worse still, someone else in the amps later life.
Best,
PD.
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Post by resonatadog on Nov 2, 2023 13:58:21 GMT
Fair comments thanks, are any of you guys electricians?
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Post by mitchfit on Nov 3, 2023 2:56:55 GMT
resonatadog,
don't feel you are being shunned here. it is more of a liability issue for responders and even the forum itself driving lack of answers. normally, members will offer any number of ideas to help with problems.
wishing you the best on your repair,
mitchfit
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Post by Michael Messer on Nov 3, 2023 8:37:15 GMT
I used to own a beautiful mid 1930s Selmer guitar amplifier. When I first got the amp it didn't work, so I took it to a very experienced and renowned amp technician. When I collected it from him, he said that it is all working as it was originally designed to do, but that it is so dangerous it should never be used. He put a large DANGER HIGH VOLTAGE sticker on the side and explained that unless it was re-wired to a more modern spec, that it should never be used with an electric guitar. There must have been a few fried guitarists back in those early days of electric guitars, especially in this neck of the woods with 240 volts going through the circuit. Needless to say I sold the amp and that was the end of that one! Wise words from PD, Pete and Mitchfit.  Shine On Michael |
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Post by Pickers Ditch on Nov 3, 2023 8:50:09 GMT
Fair comments thanks, are any of you guys electricians? No, I'm not an electrician, but I managed hi tech factories for decades and have seen the results of non qualified/non experienced people 'fixing' things many times. I'm a chemist by profession and have also seen the results of untrained people messing about with so called innocuous materials, one of whom is sadly now wandering around minus a finger and blind in one eye. Hence my statement above. |
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Post by mitchfit on Nov 3, 2023 18:42:52 GMT
like PD and pete1951, i am NOT an electrician. worked at an above ground coal mine, as well a gold mine in Alaska for many years. you'd have to read all of the testing/certifications/qualifications that MSHA requires for"sparkies" to work at mines... many of them would openly admit to being clueless about diagnosing and repairing tube/valve amps. an entirely different field, it has been a dying trade since the 70's when transistors began to take over the world. today, few ever knew or still remember that a valve amp [TV, radio, stereo or guitar] can kill you when it is unplugged from the wall power outlet. even just an olde cathode ray tube TV screen removed from the chassis. the electrical valve repair business is going the way of the dinosaur. we would be well advised to $upport them to assure some are round for future needs? most of the home computer repair techs that remain generally only replace printed circuit boards with faulty components or traces in them. usually the entire device just gets tossed, so much for trouble shooting. few know that handling a printed circuit board without gloves on has no chance of killing you. quite the opposite, YOU may kill the circuit board with just the natural electrical emissions from your body. the few techs out there who still repair the (?)outdated(?) vacuum tube amps would have to have an on hand schematic, know the physical location of heat sensitive components or be totally familiar with that circuit to guide you through a positive result solder repair. in order to remove a rare customer from a niche market share? like the first sentence says, not an electrician--as such,i have no skin in this game. just pointing out the realities of the situation. while still being all full of myself and my self proclaimed civic mindedness, there are other dangers that are not being addressed here: inspired by MM's sticker. i have sent warning stickers to some valve amp techs itself has had business dealings with. after all, they don't know everything... ...if they did, they would know i know everything also. :^) static.grainger.com/rp/s/is/image/Grainger/35JR86_AW01?$adapimg$&hei=536&wid=536mitchfit |
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Post by Michael Messer on Nov 3, 2023 20:34:48 GMT
like PD and pete1951, i am NOT an electrician. worked at an above ground coal mine, as well a gold mine in Alaska for many years. you'd have to read all of the testing/certifications/qualifications that MSHA requires for"sparkies" to work at mines... many of them would openly admit to being clueless about diagnosing and repairing tube/valve amps. an entirely different field, it has been a dying trade since the 70's when transistors began to take over the world. today, few ever knew or still remember that a valve amp [TV, radio, stereo or guitar] can kill you when it is unplugged from the wall power outlet. even just an olde cathode ray tube TV screen removed from the chassis. the electrical valve repair business is going the way of the dinosaur. we would be well advised to $upport them to assure some are round for future needs? most of the home computer repair techs that remain generally only replace printed circuit boards with faulty components or traces in them. usually the entire device just gets tossed, so much for trouble shooting. few know that handling a printed circuit board without gloves on has no chance of killing you. quite the opposite, YOU may kill the circuit board with just the natural electrical emissions from your body. the few techs out there who still repair the (?)outdated(?) vacuum tube amps would have to have an on hand schematic, know the physical location of heat sensitive components or be totally familiar with that circuit to guide you through a positive result solder repair. in order to remove a rare customer from a niche market share? like the first sentence says, not an electrician--as such,i have no skin in this game. just pointing out the realities of the situation. while still being all full of myself and my self proclaimed civic mindedness, there are other dangers that are not being addressed here: inspired by MM's sticker. i have sent warning stickers to some valve amp techs itself has had business dealings with. after all, they don't know everything... ...if they did, they would know i know everything also. :^) static.grainger.com/rp/s/is/image/Grainger/35JR86_AW01?$adapimg$&hei=536&wid=536mitchfit  |
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Post by leeophonic on Nov 4, 2023 12:56:23 GMT
I host a valve amp page on facebook for SJB Audio amps but know next to nothing around there working, but there are plenty of people out there who do know, a good amp tech is your first point to call,
Hope this helps confirm what happens next
Lee
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Post by Michael Messer on Nov 4, 2023 13:19:56 GMT
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Post by mitchfit on Nov 4, 2023 20:15:54 GMT
"Stuart is the man.... www.fixguitaramps.co.uk" what Stuart said at his website: Can I Service my Own Amp? Yes - if you know what you are doing. No, if you have no electronics knowledge. Valve amps contain potentially fatal DC voltages in excess of 400V. You don't get many second chances touching that kind of voltage! If you are not an engineer, do not even take the 'lid' off your amp! A little knowledge is a very dangerous thing with valve amps. Those voltages can be present even with the power switched off and the lead disconnected from the wall! mitchfit |
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