Home |
Search |
Today's Posts |
![]() |
|
Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
Reply |
|
|
LinkBack | Thread Tools | Display Modes |
#1
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hello all...
This is part of a longer story which I won't get into now. Suffice it to say that I've wanted to get my hands on a failed Sherwood RX-4105 or RX-4109 stereo receiver to see just what it is that kills them...abuse, misuse, weak parts, bad engineering/quality control or something else. I've never had any luck coming into a truly broken one, but someone recently gave me an RX-5502 that would just shut down right after power on. I've been very happy with all of the RX-4105 and 4109 units I own. The RX-5502 is a so-called multi-zone receiver. That is to say it can support up to eight connected pairs of speakers, with four of the pairs playing a different ("room 2") source if that is desired. It has two complete stereo amplifiers in place, each one claimed to have an output power of 100 watts per channel. (Obviously they're dreaming if they think that this receiver is ever going to output 400 total watts of power without catching fire, but...) This example was manufactured sometime in 2008. As found, this set would indeed power on for a few seconds, and shut down with a blinking standby LED. I started checking things out. In this set, the amplifier board is separate from the main board, so this was not terribly hard to do. Every power device tested good with a simple ohmmeter check, and nothing looked burnt or distressed on the amp board. This doesn't look like a case of a failed power transistor to me. I'm working without service literature or even a schematic as Sherwood would not provide them, but there is printing on the board that identifies what each conductor in the ribbon cable going to the amp board is used for. This set has a "test mode", and unlike similar models, the "test mode" allows the power to stay on indefinitely while the display test is running. Testing for voltages is a lot nicer without having to constantly turn the set back on again! Voltages are what I'd expect for B+ and B-, but a twelve volt input to the board is hovering around a few hundred millivolts at most. That could do it! Removing the amplifier board from the system and running without it was probably risky, but it seemed like a worthwhile thing to do. With the amp board removed, there was still no voltage from the +12 volt connection. It still hovered around 300mV with the set on. Interestingly, every now and then, a good power up was possible with the amp board out, and the set would come out of protection. Okay...where is the +12 volt supply generated? Over in the power supply section there are a few linear voltage regulators--two heatsinked 7812s and one freestanding 7912. One 7812 and the 7912 are doing their jobs, but the other 7812 is cold to the touch and does not seem to be doing anything. (In fact, it was putting out 300mV when I later checked it.) Replacing the failed 7812 with an LM340 solved the problem. The set immediately came back to life with the amp board in place, and it plays. It appears, based on simple observation, that one 7812 is powering the coils leading up to the speaker selection/protection relays and the other is powering the amp board itself. What other loads might be powered by these regulators has not been determined. While the set is working, I don't like the temperature at which the new regulator is running. Within ten minutes, its heatsink is on the verge of being too hot to touch for more than a few seconds. There is evidence on the circuit board that these regulators have always run very hot. I've been in touch with Sherwood America, who said "the regulator may become too hot to touch and possibly fail". I strongly suspect there are bad capacitors on the amp and main boards, which will need to be replaced and may be stressing the regulator. Yet Sherwood seems to be saying that the extremely hot operation is *normal* here. (However, it should be said that there is something of a language barrier with the folks I've been communicating with.) I could install a fan above or larger heatsink on the regulator and I'm not above doing it if that is just the way things will be. I suspect that would force the regulator to operate more reliably. What I really want to know, though, is whether or not a drop-in replacement with more current delivering capability than the LM340 or 78xx series exists. I've looked halfheartedly over the years but never found anything. I could always build a more capable regulator board and hack it in there, but I don't really feel like doing that. A fan would be easier and faster. I'd also like to know if anyone has had an RX-5502 on their repair bench, and if they could comment on just how hot its regulators were running. Any thoughts would be very much appreciated! Thank you. William |
#2
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Oct 12, 10:05*am, "William R. Walsh" wrote:
Hello all... This is part of a longer story which I won't get into now. Suffice it to say that I've wanted to get my hands on a failed Sherwood RX-4105 or RX-4109 stereo receiver to see just what it is that kills them...abuse, misuse, weak parts, bad engineering/quality control or something else. I've never had any luck coming into a truly broken one, but someone recently gave me an RX-5502 that would just shut down right after power on. I've been very happy with all of the RX-4105 and 4109 units I own. Why would you care so much about some Korean POS? Sherwood was once a fine Chicago company, from the era when Chicago was the consumer electronics center of the world. |
#3
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
I've been in touch with Sherwood America, who said "the
regulator may become too hot to touch and possibly fail". William Well there you go, the manufacturer has backed up your observations that this regulator does indeed run very hot. Its not that uncommon to find this kind of thing. Stick a heatsink on it. Job done. Gareth. |
#4
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
Why would you care so much about some Korean POS? Well, because I can? Because I like 'em? Because the internal design is pretty clean and straightforward? Because I like their sound and think they're a pretty damn good modern receiver? Maybe because it's just one other thing that won't end up in the landfill? Has the purpose of this group changed since I was last here? That's not the question I asked, or the information I wanted. Pulling out my IR thermometer reveals that the regulator really isn't getting as hot as I thought it was...about 124F or so at its hottest point. I'll not worry about it further, though I probably will add a fan powered by the lesser loaded regulator. William |
#5
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
Stick a heatsink on it. *Job done. It's already got a goodly sized heatsink on it. In fact, I couldn't find anything bigger in the TO-220 category. Operating temps turn out not to be as bad as I thought--about 124F at most. Perhaps the original regulator was just defective. I'll never know. I will probably just run a fan from the other, less loaded regulator and suspend it over the circuit board. That would be a lot less work than milling some scrap heatsinks from old PC power supplies down to fit. William |
#6
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
"Gareth Magennis" wrote in message
... I've been in touch with Sherwood America, who said "the regulator may become too hot to touch and possibly fail". William Well there you go, the manufacturer has backed up your observations that this regulator does indeed run very hot. Its not that uncommon to find this kind of thing. Stick a heatsink on it. Job done. Gareth. Sherwood makes receivers for many others, and there is a common problem the past several years with cheap fixed regulators failing. Mostly 79 series 12 and 15 volt regs but also 78 series positive types. They are heatsinked, but fail anyway. Mark Z. |
#7
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Oct 12, 2:53*pm, "William R. Walsh" wrote:
Hi! Why would you care so much about some Korean POS? Well, because I can? Because I like 'em? Because the internal design is pretty clean and straightforward? Because I like their sound and think they're a pretty damn good modern receiver? Maybe because it's just one other thing that won't end up in the landfill? Has the purpose of this group changed since I was last here? Your purpose in coming here seemed quite quixotic, not to say masochistic, and therefore provoked curiosity: "Suffice it to say that I've wanted to get my hands on a failed Sherwood RX-4105 or RX-4109 stereo receiver to see just what it is that kills them...abuse, misuse, weak parts, bad engineering/quality control or something else. " Hard to imagine anything other than frequent failure would provoke this quest. A likely parallel in the automotive world would be a mission to isolate failure modes of the Yugo. Regarding the purpose of the group: Generally people come here to get information to help them repair various pieces of electronic equipment, often because their livelihood depends on it. Instead, you want advice so you can redesign this run of the mill receiver for greater reliability. That's not the question I asked, or the information I wanted. Pulling out my IR thermometer reveals that the regulator really isn't getting as hot as I thought it was...about 124F or so at its hottest point. I'll not worry about it further, though I probably will add a fan powered by the lesser loaded regulator. Why clutter up such a clean and straightforward internal design with adequate cooling? |
#8
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Wed, 12 Oct 2011 10:05:18 -0700 (PDT), "William R. Walsh"
wrote: (snip) What I really want to know, though, is whether or not a drop-in replacement with more current delivering capability than the LM340 or 78xx series exists. I've looked halfheartedly over the years but never found anything. I could always build a more capable regulator board and hack it in there, but I don't really feel like doing that. A fan would be easier and faster. Alternative 3-terminal linear regs will still dissipate the same amount of heat regardless of their current capability. If the problem is in the load (i.e. faulty components) then that should be where you focus your attention. If the real problem is the load current and the consequent thermal issues (i.e marginal/poor design vs SOA) then measure the actual load current and consider a drop-in switcher such as the (TI) PT78T112V or (RECOM) R-7812. |
#9
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On 10/12/2011 12:05 PM, William R. Walsh wrote:
What I really want to know, though, is whether or not a drop-in replacement with more current delivering capability than the LM340 or 78xx series exists. Actually, it sounds more like they blew the design by having too much input voltage for the output voltage and current. As a modest example of what I mean: 18V input 12V output at 1 amp. This is 6 watts dissipation at the regulator package. 24V input 12V output at 1 amp. This is 12 watts dissipation at the regulator package. http://www.datasheetcatalog.org/datasheets2/52/529144_1.pdf Doesn't specifically give a voltage drop vs output current derating curve. But I would think that adding a bit of series resistance to the input side and letting some of the waste heat go away there would go a long way towards extending the life of the regulator package. Jeff -- "Everything from Crackers to Coffins" |
#10
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() "William R. Walsh" wrote in message ... Hi! Stick a heatsink on it. Job done. It's already got a goodly sized heatsink on it. In fact, I couldn't find anything bigger in the TO-220 category. Operating temps turn out not to be as bad as I thought--about 124F at most. Perhaps the original regulator was just defective. I'll never know. I will probably just run a fan from the other, less loaded regulator and suspend it over the circuit board. That would be a lot less work than milling some scrap heatsinks from old PC power supplies down to fit. William Oops, should have read your post properly, it was a long hard day yesterday and today I have aches and pains to remind me. Gareth. Gareth. |
#11
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Wed, 12 Oct 2011 10:05:18 -0700 (PDT) "William R. Walsh"
wrote in Message id: : What I really want to know, though, is whether or not a drop-in replacement with more current delivering capability than the LM340 or 78xx series exists. I've looked halfheartedly over the years but never found anything. I could always build a more capable regulator board and hack it in there, but I don't really feel like doing that. A fan would be easier and faster. These will go up to 3A. http://search.digikey.com/us/en/prod...1118-ND/771587 Bottom line is that it's the heatsink and the voltage in that will determine whether you'll actually get 3A. |
#12
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
Your purpose in coming here seemed quite quixotic, not to say masochistic, and therefore provoked curiosity: I've never been described in quite that way before. ;-) Hard to imagine anything other than frequent failure would provoke this quest. To the contrary...I have a number of these sets used in various applications. All are well treated and used under reasonable conditions. I've never had a failure, even when making heavy demands from the set. The one time I accidentally shorted a pair of speaker wires, the set's protection functioned just as it should and there was no lasting damage. Yet I look around on the 'net and see people saying "well, the Sherwood unit blew up, blew sparks and smoke, shuts off past a certain volume level or just shut down one day, never to turn on again". What few repairs I've seen done suggested that blown final transistors or bad filter caps were the cause. My experiences don't align with what people were saying. I have no particularly good reason for wanting to know other than to say I am eternally curious. "Why?" is one of my favorite questions. As proof that I have no shortage of obnoxious opinions, troubleshooting and repairing this receiver was arguably more worthwhile than watching what passes for television these days. Regarding the purpose of the group: Generally people come here to get information to help them repair various pieces of electronic equipment, often because their livelihood depends on it. Instead, you want advice so you can redesign this run of the mill receiver for greater reliability. Not totally. I wanted to share what I found, in the case that other people here, who might someday be faced with the same situation, could potentially find a solution. Though I've not been here for a while, I am not new to the group or its purpose. Your initial response was taken to mean more of a "why would I bother repairing that piece of junk". If I think that something I've repaired could break in the same way, making a better repair or improvement to the design is something I'd go ahead and do, provided it does not involve a massive reworking. As I have never found any simple linear regulator better spec'd than the 78xx series, I thought I'd throw the question in while I was here. I don't do this professionally, nor do I have the audacity to claim that I am a professional. I'm just someone who knows a modest amount and takes an interest from the sidelines. Why clutter up such a clean and straightforward internal design with adequate cooling? No doubt the unit was designed to a price. Who could say what the original designers had in mind...or maybe they just made a mistake. It has to be said that Sherwood has been (mostly) helpful along the course of this repair, much more so than the competion (Sony and TEAC). William |
#13
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
Alternative 3-terminal linear regs will still dissipate the same amount of heat regardless of their current capability. Okay...if you don't mind my asking, why is that the case? It would seem to me that a more capable part asked to do the same work as a less capable part would have an easier time of it. If the problem is in the load (i.e. faulty components) then that should be where you focus your attention. There does not appear to be any problem with anything that is powered by the regulator's output (though I do have some suspicious caps to replace elsewhere). William |
#14
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
Actually, it sounds more like they blew the design by having too much input voltage for the output voltage and current. The regulator is supplied with 25 volts. While I hadn't really looked at the curves and figures, what they are doing did not sit well with me from the outset. Why ask the regulator to do that much work? But I would think that adding a bit of series resistance to the input side and letting some of the waste heat go away there would go a long way towards extending the life of the regulator package. I had not thought of this and might just sit down and do the math to see what I'd need. What I do will depend upon whether or not there is room to put something in place without going to extremes. William |
#15
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
They are heatsinked, but fail anyway. The regulator I replaced had a fully plastic body, and I wonder if this did not help to accelerate its demise. The replacement part is a Motorola/OnSemi LM340 with a metal tab. It seems to me like this would work better at shedding heat than a fully plastic body. William |
#16
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
"William R. Walsh" writes:
Alternative 3-terminal linear regs will still dissipate the same amount of heat regardless of their current capability. Okay...if you don't mind my asking, why is that the case? Because that's how linear regulators work -- they behave like a sort of intelligent resistor. If you regulate 28V down to 12V with a linear regulator, the regulator acts like the right value of resistor to get rid of 16V as heat. You can do better with more modern regulators, but you need a switching regulator rather than a linear one. National's "Simple Switcher" regulators are good for this sort of thing; you pretty much just add an external capacitor and inductor. -- Adam Sampson http://offog.org/ |
#17
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
In article ,
Adam Sampson wrote: Because that's how linear regulators work -- they behave like a sort of intelligent resistor. If you regulate 28V down to 12V with a linear regulator, the regulator acts like the right value of resistor to get rid of 16V as heat. You can do better with more modern regulators, but you need a switching regulator rather than a linear one. National's "Simple Switcher" regulators are good for this sort of thing; you pretty much just add an external capacitor and inductor. Murata now has some interesting little switching regulators which "mimic" a 7805 - they have the same pinout, same current capacity, and are built on a small PC board which is roughly the size and shape of a TO-220. I recently installed one in an old MFJ packet-terminal node controller (TNC). THe original TNC design uses a 7805, with a small clip-on heatsink, and a thoroughly-incompetent attempt to couple the heatsink to the case for additional heat transfer (they gooped the heatsink surface with silicone compound, but did *not* actually fasten the heatsink to the case!). Even with the clip-on heatsink, the 7805 was running quite hot... not too hot to touch, but warmer than I like. The Murata part dropped right in, requires no heatsink, works nicely, and it's barely warm to the touch. As with any decision to substitute a switching regulator for a linear regulator, you'll need to consider the output noise - it might be too much for an audio amplifier to tolerate. Or, one or more additional stages of filtering may be required. These Murata parts are about $4.50 each in onesies, through Mouser. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#18
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Thu, 13 Oct 2011 08:57:08 -0700 (PDT), "William R. Walsh"
wrote: Hi! Alternative 3-terminal linear regs will still dissipate the same amount of heat regardless of their current capability. Okay...if you don't mind my asking, why is that the case? It would seem to me that a more capable part asked to do the same work as a less capable part would have an easier time of it. It WILL have an easier time of it but OTOH it will still require dissipation of the same amount of heat. If the problem is in the load (i.e. faulty components) then that should be where you focus your attention. There does not appear to be any problem with anything that is powered by the regulator's output (though I do have some suspicious caps to replace elsewhere). William |
#19
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() |
#20
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
In article ,
who where wrote: Murata now has some interesting little switching regulators which "mimic" a 7805 - they have the same pinout, same current capacity, and are built on a small PC board which is roughly the size and shape of a TO-220. Although I didn't say so explicitly, the two devices I mentioned are also TO-220 "drop-in" switchers. It is certainly an emerging market area. The "Simple Switcher" (tm) parts I have seen up until now, have the switcher controller, but you need to install external components (inductor, etc.)., so their pinout isn't directly 7805-compatible. The Murata parts have all of that on their own PCB - no additional external components are required, if you can live with their output levels. I would expect to see other manufacturers come up with these sorts of complete drop-in-ready modules. -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
#21
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Thu, 13 Oct 2011 09:03:39 -0700 (PDT), "William R. Walsh"
put finger to keyboard and composed: But I would think that adding a bit of series resistance to the input side and letting some of the waste heat go away there would go a long way towards extending the life of the regulator package. I had not thought of this and might just sit down and do the math to see what I'd need. What I do will depend upon whether or not there is room to put something in place without going to extremes. I agree that's the simplest solution. In fact I've done similar things in lots of gear, including a 586 motherboard. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#22
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Hi!
These Murata parts are about $4.50 each in onesies, through Mouser. If I've found the right part, I reckon you are speaking of the 7812SR/ SRH-C regulators. These look like interesting devices but the low current rating may be a problem. I need to rig up a way to see what the current draw actually is. I don't think noise in the circuit would be a problem, this regulator appears to be powering a protection circuit. I've not traced the circuit to know exactly what it's powering beyond that. William |
#23
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
Den 12-10-2011 19:05, William R. Walsh skrev:
Hello all... This is part of a longer story which I won't get into now. Suffice it to say that I've wanted to get my hands on a failed Sherwood RX-4105 or RX-4109 stereo receiver to see just what it is that kills them...abuse, misuse, weak parts, bad engineering/quality control or something else. I've never had any luck coming into a truly broken one, but someone recently gave me an RX-5502 that would just shut down right after power on. I've been very happy with all of the RX-4105 and 4109 units I own. The RX-5502 is a so-called multi-zone receiver. That is to say it can support up to eight connected pairs of speakers, with four of the pairs playing a different ("room 2") source if that is desired. It has two complete stereo amplifiers in place, each one claimed to have an output power of 100 watts per channel. (Obviously they're dreaming if they think that this receiver is ever going to output 400 total watts of power without catching fire, but...) This example was manufactured sometime in 2008. As found, this set would indeed power on for a few seconds, and shut down with a blinking standby LED. I started checking things out. In this set, the amplifier board is separate from the main board, so this was not terribly hard to do. Every power device tested good with a simple ohmmeter check, and nothing looked burnt or distressed on the amp board. This doesn't look like a case of a failed power transistor to me. I'm working without service literature or even a schematic as Sherwood would not provide them, but there is printing on the board that identifies what each conductor in the ribbon cable going to the amp board is used for. This set has a "test mode", and unlike similar models, the "test mode" allows the power to stay on indefinitely while the display test is running. Testing for voltages is a lot nicer without having to constantly turn the set back on again! Voltages are what I'd expect for B+ and B-, but a twelve volt input to the board is hovering around a few hundred millivolts at most. That could do it! Removing the amplifier board from the system and running without it was probably risky, but it seemed like a worthwhile thing to do. With the amp board removed, there was still no voltage from the +12 volt connection. It still hovered around 300mV with the set on. Interestingly, every now and then, a good power up was possible with the amp board out, and the set would come out of protection. Okay...where is the +12 volt supply generated? Over in the power supply section there are a few linear voltage regulators--two heatsinked 7812s and one freestanding 7912. One 7812 and the 7912 are doing their jobs, but the other 7812 is cold to the touch and does not seem to be doing anything. (In fact, it was putting out 300mV when I later checked it.) Replacing the failed 7812 with an LM340 solved the problem. The set immediately came back to life with the amp board in place, and it plays. It appears, based on simple observation, that one 7812 is powering the coils leading up to the speaker selection/protection relays and the other is powering the amp board itself. What other loads might be powered by these regulators has not been determined. While the set is working, I don't like the temperature at which the new regulator is running. Within ten minutes, its heatsink is on the verge of being too hot to touch for more than a few seconds. There is evidence on the circuit board that these regulators have always run very hot. I've been in touch with Sherwood America, who said "the regulator may become too hot to touch and possibly fail". I strongly suspect there are bad capacitors on the amp and main boards, which will need to be replaced and may be stressing the regulator. Yet Sherwood seems to be saying that the extremely hot operation is *normal* here. (However, it should be said that there is something of a language barrier with the folks I've been communicating with.) I could install a fan above or larger heatsink on the regulator and I'm not above doing it if that is just the way things will be. I suspect that would force the regulator to operate more reliably. What I really want to know, though, is whether or not a drop-in replacement with more current delivering capability than the LM340 or 78xx series exists. I've looked halfheartedly over the years but never found anything. I could always build a more capable regulator board and hack it in there, but I don't really feel like doing that. A fan would be easier and faster. I'd also like to know if anyone has had an RX-5502 on their repair bench, and if they could comment on just how hot its regulators were running. Any thoughts would be very much appreciated! Replace the burning hot 7812 with one of these: http://www.dimensionengineering.com/...s/DE-SWADJ.pdf I have no connection to the company only thinks their product is sweet. -- Uffe Bærentsen |
#24
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
responding to
http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: Thank you so much for the info. I found the 7812 that powered the amp to be bad. A $2 radio shack part and a little time, and my RX-5502 is back up and operational. Mine was shutting down exactly as you described and after replacing the 7812, it has played music for over two hours and is still doing great. |
#25
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
You realize this is five years old and some of these people could be dead.
It might be nice to resurrect threads on websites that simply copy Usenet but have no content of their own, but to respond to it on Usenet is not nice. Some people get ****ed off. Some people pull up **** from like 1991. this was even here in 1991 ? I mean, some cars still had carbs back then. They never heard of radon gas. Like a different world. |
#26
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() |
#27
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Thu, 14 Jan 2016, Kaz Kylheku wrote:
On 2016-01-14, wrote: You realize this is five years old and some of these people could be dead. It might be nice to resurrect threads on websites that simply copy Usenet but have no content of their own, but to respond to it on Usenet is not nice. Some people get ****ed off. Threads about a fixing particular piece of consumer electronic equipment tend to be old. If someone has *new* information to add, like "I fixed a similar problem with the same unit, and it went like this" it's perfectly fine; there is nothing wrong with referencing the old thread. No it's not fine. This is not google, where the messages all appear. usenet was never intended to be archived. SOme idiot replying to an old thread isn't being part of the newsgroup, they are simply doing google. ANd whether or not that's good, the blunders pile on. They don't quote, they don't acknowledge they are replying to an old message, they may not even have a proper subject header (so instead of "" so we know it's a reply, it can often look like the start of a thread. Without quoting, there's no context, the only reason the post makes sense is because other idiots before them have done the same thing, so it's most likely a google idiot post. The reality is people are replying to old threads for reasons that aren't clear, but I suspect some of it is that they simply don't grasp where they are, or that they are replying to an old thread. And too often, someone replies to an old thread, and others jump in as if the thread is new, because they are reading at google and the thread then "comes to the top" and starts replying to the old thread. Too often, those people haven't even read the old thread, so they are not adding anything to it. Or, the person replying to the old thread gets replies, again as if the thread is new. Often the old thread has covered the problem, and anything new is just repetition. We had a resurrected thread last year here, and it wasn't so old, so some of the original participants replied, a second time, and gave about the same answer as they did the first (and in that thread, the original poster had posted a followup, back then, to reveal what solution had worked for them). That's on top of the stupid posts where people ask a 1991 post "is this thing still for sale?" or the like. Don't try to justify this based on a specific newsgroup, the problem is that google still hasn't fixed the bug that allows replies to messages older than 30 days. You want everything neat and tidy in one place, but that doesn't happen. And the same search that found the original thread should indeed find any separate followup thread that someone posted much later. Our place here isn't to deal with the future, at google, our place here is an ongoing discussion of the repair of electronic equipment (or whatever the newsgroup is intended for, if this was another newsgroup). Look, you're just not going to find a current, continuous, day-to-day discussion thread on a darned Sherwood RX-5502, right? You're assuming that people only ask about current equipment. I've read this newsgroup since late 1994, and when I got full internet access in 1996, dejanews had already started archiving usenet posts. That was neat, because every time I dragged home some neat piece of equipment from a garage or rummage sale, I'd do a search, and often find some bit of information about the new junk. If I'd needed to ask something, I'd not reply to an old thread (and that option wasn't there with dejanews). But if I'd wanted to ask about something I just dragged home, I'd post away. And maybe someone would have information, maybe not, it depends on who is reading the newsgroup. Any of the idiots who keep replying to old threads is welcome to be a member of this newsgroup, all they have to do is post a message, if they want to talk about something old, that's okay too. Just don't reply to an old message. But if you start trying to help that person from seven years ago by asking questions, like "does the front panel light up, or is it completely dead?" then you're indeed a necroposting moron who annoys people, and probably shouldn't be using any device that has a CPU and network connection. But when some idiot replies to an old post, here it's not so obvious (except because there are telltales that we notice after the repeated abuse), so others chime in to the old thread as if it is new. So whether or not the first replier has some good thing to add, it's distruptive to the newsgroup. Forget about google, act here like this is Usenet, which it is. Messages fade with time, unless someone saves them to their own hard drive. It's nto intended to be a long term medium. So don't treat it like it is. Anyone can post and say "there was a discussion ten years ago, and I thought I'd add some more insight", they can even reference the old message, or "I just got this new thing, so I thought I'd post some comments about it". They don't need to rely on someone previously posting about it. Michael |
#28
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
I don't know how you get here, but Google and aioe or whatever seem to be the only free ways to do it. Actually I probably should get a paid service but then, who gets that money ? Originally I got here via AOL but they stopped doing everything I wanted so I got rid of them.
Anyway, in Google the topics are arranged in reverse chronological order, sorted by most recent post. The date is right there, but it gives the latest date. So if it bugs you it bugs me more because I see on the right it says "4 hours ago", then I open it up and it does not skip the old posts because I have not read them through Google. Believe it or not I may have read or even be in some of these old posts. But that doesn't matter, most of my work was TVs so therefore it is all useless knowledge. Audio equipment is a different story. People are repairing and restoring old stuff every day, to the tune of mucho dinero I might add. One guy I did a job for in PA wound up with $600 into the repair. Half of that was the round trip on UPS, and they broke it ! I actually could have charged him more but I have him some money off because I put a scuff mark on the front panel. It is a Mitsubishi X-11 system with the vertical turntable. I had to fix the amp which meant retrofitting it to modern chips because the original is unobtanium, but before that I had to fix the power supply with a foil burnt off the board, which was quite worrisome at first. I had to fix a broken part in the cassette deck and put belts in that. Then when it got home, UPS somehow screwed up the TT tracking servo. I had to charge him another hundred for that but that included time and gas to meet him about halfway. We were not about to do UPS again. so about $700 for like a 25 watt per channel, magnetic cartridge (oh I replaced that also) and a pretty decent cassette deck. Although he'll never need outputs again, I used LM3886s. At any rate, back to our regularly scheduled hijack, the people who respond to these old posts, like you said, must be finding them through a search. I mean a web search. for them to search SER, they would have to go to SER first, right ? However, I just Googled for "Sherwood RX-5502" and no hits with "groups" on the first two pages. [ Then there is another thing, a bunch of websites archive Usenet and pretend they got a forum. Could they be finding these old posts that way ? I mostly agree with you, but not with the preventing replies to posts over a month old. I think six months would be good. At least there's a good chance the people are still alive. |
#29
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
responding to
http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: I just wanted to say thank you. I didn't realize that was so bad!! |
#30
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() |
#31
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
responding to
http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: jurb6006 wrote: I don't know how you get here, but Google and aioe or whatever seem to be t he only free ways to do it. Actually I probably should get a paid service b ut then, who gets that money ? Originally I got here via AOL but they stopp ed doing everything I wanted so I got rid of them. Anyway, in Google the topics are arranged in reverse chronological order, s orted by most recent post. The date is right there, but it gives the latest date. So if it bugs you it bugs me more because I see on the right it says "4 hours ago", then I open it up and it does not skip the old posts becaus e I have not read them through Google. Believe it or not I may have read or even be in some of these old posts. But that doesn't matter, most of my wo rk was TVs so therefore it is all useless knowledge. Audio equipment is a d ifferent story. People are repairing and restoring old stuff every day, to the tune of mucho dinero I might add. One guy I did a job for in PA wound u p with $600 into the repair. Half of that was the round trip on UPS, and th ey broke it ! I actually could have charged him more but I have him some mo ney off because I put a scuff mark on the front panel. It is a Mitsubishi X -11 system with the vertical turntable. I had to fix the amp which meant re trofitting it to modern chips because the original is unobtanium, but befor e that I had to fix the power supply with a foil burnt off the board, which was quite worrisome at first. I had to fix a broken part in the cassette d eck and put belts in that. Then when it got home, UPS somehow screwed up th e TT tracking servo. I had to charge him another hundred for that but that included time and gas to meet him about halfway. We were not about to do UP S again. so about $700 for like a 25 watt per channel, magnetic cartridge ( oh I replaced that also) and a pretty decent cassette deck. Although he'll never need outputs again, I used LM3886s. At any rate, back to our regularly scheduled hijack, the people who respond to these old posts, like you said, must be finding them through a search. I mean a web search. for them to search SER, they would have to go to SER f irst, right ? However, I just Googled for "Sherwood RX-5502" and no hits with "groups" on the first two pages. [ Then there is another thing, a bunch of websites archive Usenet and pretend they got a forum. Could they be finding these old posts that way ? I mostly agree with you, but not with the preventing replies to posts over a month old. I think six months would be good. At least there's a good chan ce the people are still alive. If you really care to know--I did a goggle search and found the info on electrodepot.com. I replied through that web site. I have no idea what Usenet is. I just know there is at least one ass that like calling people idiots |
#32
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
T Wood wrote: "electrodepot.com. I replied through that web site. I have no idea what Usenet
is. I just know there is at least one ass that like calling people idiots " Most folks born after 1980 wouldn't. Basically, usenet WAS the internet. A worldwide "distributed discussion system" according to Wikipedia: https://en.m.wikipedia.org/wiki/Usenet And many traditional Usenet users become very irate and take it personal when someone - like me - interacts with usenet groups via Google or some other non-standard usenet interface. What they see coming into the group from a non-NNTP source is out of the ordinary that the context of the message is lost. But still, no reason for them to be jerks about it. ![]() |
#33
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Wednesday, January 13, 2016 at 11:37:04 PM UTC-5, T Wood wrote:
responding to http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: Thank you so much for the info. I found the 7812 that powered the amp to be bad. A $2 radio shack part and a little time, and my RX-5502 is back up and operational. Mine was shutting down exactly as you described and after replacing the 7812, it has played music for over two hours and is still doing great. I have had the same problem with my RX-5502. Can you tell me what the $2 Radio Shack part is? I looked at the thread you quoted and did not see a reference to the part name or number. Thanks! |
#34
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Sunday, March 4, 2018 at 3:02:22 PM UTC-5, wrote:
On Wednesday, January 13, 2016 at 11:37:04 PM UTC-5, T Wood wrote: responding to http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: Thank you so much for the info. I found the 7812 that powered the amp to be bad. A $2 radio shack part and a little time, and my RX-5502 is back up and operational. Mine was shutting down exactly as you described and after replacing the 7812, it has played music for over two hours and is still doing great. I have had the same problem with my RX-5502. Can you tell me what the $2 Radio Shack part is? I looked at the thread you quoted and did not see a reference to the part name or number. Thanks! Honestly, if "7812" and "regulator" don't ring any bells, you probably shouldn't be screwing around with this. It could not have been any more easy unless someone dispatches a courier to your home with one. |
#35
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Sunday, 4 March 2018 20:02:22 UTC, wrote:
On Wednesday, January 13, 2016 at 11:37:04 PM UTC-5, T Wood wrote: responding to http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: Thank you so much for the info. I found the 7812 that powered the amp to be bad. A $2 radio shack part and a little time, and my RX-5502 is back up and operational. Mine was shutting down exactly as you described and after replacing the 7812, it has played music for over two hours and is still doing great. I have had the same problem with my RX-5502. Can you tell me what the $2 Radio Shack part is? I looked at the thread you quoted and did not see a reference to the part name or number. Thanks! he told you, the 7812. |
#36
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Sunday, March 4, 2018 at 6:02:16 PM UTC-5, wrote:
On Sunday, 4 March 2018 20:02:22 UTC, wrote: On Wednesday, January 13, 2016 at 11:37:04 PM UTC-5, T Wood wrote: responding to http://www.electrondepot.com/repair/...ug-134725-.htm , T Wood wrote: Thank you so much for the info. I found the 7812 that powered the amp to be bad. A $2 radio shack part and a little time, and my RX-5502 is back up and operational. Mine was shutting down exactly as you described and after replacing the 7812, it has played music for over two hours and is still doing great. I have had the same problem with my RX-5502. Can you tell me what the $2 Radio Shack part is? I looked at the thread you quoted and did not see a reference to the part name or number. Thanks! he told you, the 7812. Ah, yes. Sorry, for some reason I got it into my head that he replaced it with something different (and better). And to John-Del's point, I have no intention of getting in over my head with this; I am just mad that a product I paid a fair amount of money for stopped working after 4 hours of use. If I can find someone local to fix it, I will. Otherwise I'll move on with my life. |
#37
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
What is local ? I fix these things.
|
#38
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() |
#39
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]() |
#40
![]()
Posted to sci.electronics.repair
|
|||
|
|||
![]()
On Tuesday, 6 March 2018 06:32:03 UTC, Fox's Mercantile wrote:
On 3/6/18 12:16 AM, wrote: In the end I was lucky to get about $2 an hour for my time. Not a very effective use of your time. No, but we've all had jobs where that became true, more so when young. NT |
Reply |
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
Sherwood RX-4105/4109 and Insignia NS-R2000 stereo receiver take apart/teardown/exploration | Electronics Repair | |||
Sherwood S-8300Cp receiver help | Electronics Repair | |||
Sansui Receiver- Noise at shutdown | Electronics Repair | |||
Sony STR-D865 Receiver "Protection" mode | Electronics Repair | |||
HV protection for receiver input? | Electronics Repair |