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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. |
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#1
Posted to sci.electronics.repair,sci.electronics.design
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Power switch is erratic on receiver
I picked up a used Koss HH375 receiver at a Goodwill store. It's purpose
is to power some speakers for my computer's sound. Although this is no high powered amplifier, it does the job, and sounds 100 times better than those cheap "amplified computer speakers". But it has a "bug". The power switch is erratic. Sometimes I have to push it 5 or more times to get it to "latch on". (and the same to shut it off). Once and awhile, it even turns itself off, when in use. Worse yet, often when I turn it on, there is no sound. I have to push the "up/down" volume switches. My original thought was to just never turn it off, and to put a switch on the power cord. I soon found this will not work. If I unplug it, it's OFF the next time I plug it in. I have not yet opened it up, but plan to do so. But there must be a problem beyond dirty switch contacts, because of that volume control issue. I should mention that this receiver was designed to be used with a remote control (which I do not have). That tells me that the switch is INSIDE the circuit, not just a power line toggle switch. And that's where I tend to get lost...... On top of that, I have not found anything as far as a schematic online. I'm a guy who has worked on a lot of tube equipment, but this modern stuff is not my cup of tea..... Anyone have any idea how this thing works or what to look for??? I'd like to fix it if I can, just because it has very nice sound quality. Otherwise I'd just replace it with another amp. I did not pay much for it, so it's no big deal, but I'll give it a shot, if I know a little more what I am facing! |
#2
Posted to sci.electronics.repair,sci.electronics.design
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Power switch is erratic on receiver
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#3
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Power switch is erratic on receiver
https://www.flickr.com/photos/kriswood/5498051786
This (bottom unit)? It was made by a division of Koss that is defunct and no longer supporting its products, in a mix of Singapore, Taiwan, China, Japan and Korea - quite a range. I am speculating given that this is an R/C unit, which typically requires special internal controls. By the way, replacement remotes are readily available from the likes of Amazon and others. Very likely a solid-state volume control - nothing you can get to or clean. Possibly a stepper volume control which uses a small motor and a conventional VC. Those you can get to and clean. The on/off switch is likely a latching reed relay, about the size of a large squared-off jelly bean. You would have to replace this outright. Can you say "PITA"? Do not clean the slide controls with conventional contact cleaner. That will require a cleaner formulated to those types of controls. It may comes to pass that with sufficient exercise, the controls will clean themselves. If not, you will have to troubleshoot on a component level, that is part-by-part. Given its purpose, I suggest you live with its quirks as from your description, it eventually does work. By the time you are done with it, unless you are exceedingly lucky or there is a directly visible problem, it will likely not work. Peter Wieck Melrose Park, PA |
#4
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Power switch is erratic on receiver
rickman wrote: "I have a pair of Sony's that sound nice to me. But they
use an audio cable and I prefer Bluetooth." What's wrong with running a cable? Besides, a hard connection will always sound better than Bluetooth, or other wireless means. "I installed an eBay module in one, but it quit working after a year or so." An "eBay module"? You mean you tried to make the speakers pick up sound wirelessly? -- Rick C |
#5
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Power switch is erratic on receiver
If the switch is mechanical there is a way to wire it to be always on. Just do that, and just leave it on.
I know you can't do that with tubes or class A stuff, but a regular class AB amp will be fine. And usually it will sound better and better as it burns in. Just leave it on forever. I do with mine, and I do not see a huge electric bill or anything. They might pull about three clock radios worth of power, which is about nothing. I mean like a dollar a month if that. |
#6
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Power switch is erratic on receiver
On Sunday, March 19, 2017 at 4:21:16 PM UTC-4, wrote:
If the switch is mechanical there is a way to wire it to be always on. Just do that, and just leave it on. Hmmm.. functional but no charm... Here's what he needs: http://www.antiquesnavigator.com/d-3...te-copper.html Four sheet metal screws and some hookup wire and he's back in business. Plus, he gets the added benefit of saying "muwahahahaha" every time he turns it on.. |
#7
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Power switch is erratic on receiver
CRC electronics cleaner at Walmart.
ask Al for a switch lubricant http://www.alliedelec.com/chemicals-...es/lubricants/ |
#8
Posted to sci.electronics.repair,sci.electronics.design
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Power switch is erratic on receiver
wrote in message ... I picked up a used Koss HH375 receiver at a Goodwill store. It's purpose is to power some speakers for my computer's sound. Although this is no high powered amplifier, it does the job, and sounds 100 times better than those cheap "amplified computer speakers". Just get some Altec-Lansing PC speakers (I did - several pairs). The ones I have are basic single drive units, the plastic cases are sturdy and they sound pretty good. One pair was thrown in with a refurb PC - the rest came from a free recycling group. |
#9
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Power switch is erratic on receiver
On Sun, 19 Mar 2017 05:25:51 -0700 (PDT), "
wrote: If not, you will have to troubleshoot on a component level, that is part-by-part. Given its purpose, I suggest you live with its quirks as from your description, it eventually does work. By the time you are done with it, unless you are exce edingly lucky or there is a directly visible problem, it will likely not work. {Quotes snipped because of line length] Yea, it does eventually work, but it also will occasionally shut itself off right in the middle of some music or something. There is no rhyme of reason that it shuts off, but it does and all the LEDS and everything go off. From what you described, I doubt I want to evne mess with it. This is the kind of stuff I dont like working on. I may take a look inside, but I think it's time to begin looking for another amp, and one that's older. I prefer tube amps for an actual stereo system, but for a computer amp, a decent older transistorized unit would be fine. This has a radio, but I dont need it. All I need is a power amp with a AUX or TAPE input. I find it disturbing that Koss is out of business, I remember when they were the top of the line for headphones. |
#10
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Power switch is erratic on receiver
Koss is doing just fine. Their electronics division is gone. Historically, many transducer companies, starting with KLH, AR, Advent, ADS and many others have run aground when attempting electronics. Why should Koss be any different?
Peter Wieck Melrose Park, PA |
#11
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Power switch is erratic on receiver
On Wednesday, March 22, 2017 at 7:08:22 AM UTC-4, wrote:
Koss is doing just fine. Their electronics division is gone. Historically, many transducer companies, starting with KLH, AR, Advent, ADS and many others have run aground when attempting electronics. Why should Koss be any different? Peter Wieck Melrose Park, PA ARE these companies from New England ? the switch problem rests in the function. switches generally last as switches live a low stress life. except for rotaries, possibly emergency switches in mobile units, switches just slid n switch. there's a axle or pivots ? any signs of wear .... in the Gobi for 20 years .... so if the switch is sprayed with cleaner n lubricant.... once twice three times CRC is used as a pressure flow device...the switch should resume switching. there's one here near the floor had several doses of fruit juice. intermittent but cleaned wroks good. I'll look for the Koss .. KLOSS .... https://www.google.com/#q=koss+KLH,+...STRY&*&spf=895 the forum has historians |
#13
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Power switch is erratic on receiver
On Wed, 22 Mar 2017 04:08:20 -0700 (PDT), "
wrote: Koss is doing just fine. Their electronics division is gone. Historically, many transducer companies, starting with KLH, AR, Advent, ADS OK, now I know that.... I'm sure this receiver was just rebranded by Koss. If I could find out who made the thing, I could probably find a schematic for it. But how to find that out seems near impossible. Since you mentioined KLH, the speakers I am using are KLH brand. Great sounding for their small size. |
#14
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Power switch is erratic on receiver
Funny thing about this. As one who focuses primarily on legacy equipment I own one KLH Table Radio.
I own six (6) sets of AR speakers, all from the Teledyne days, all in active service from 3as through Athenas. I also own one-each of their amps, receivers and tuners. I own an Advent 500 SoundSpace control and a 100A dual-Dolby unit (matched to my Revox A77). I own a pair of ADS speakers out on loan. I own three pairs of Koss headphones, including their electrostatics. Other equipment in the inventory includes: Revox A77, A720 & 722, B225, B215, B290 Harman Kardon Citation 16, 17, 18 & 19, ST7, ST8, HK2000 Cassette. And several shelves of Dynaco tube and solid-state. Main speakers are Maggies. Multiple Sony Changers, 200 & 5 disc, all from thrift-shops. So apart from the Revox, Sony and the HK2000, everything is from the US and from 'back in the day'. Much of it via dumpster-dives, and purchasing repair-shop leavings as my eyes and ears have always been larger than my wallet.. I did drive 1,200 miles round-trip for the Maggies, however, after a friend auditioned them in-situ. The price was that good. They are truly worth it. Peter Wieck Melrose Park, PA |
#15
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Power switch is erratic on receiver
On Wed, 22 Mar 2017 12:19:14 -0700 (PDT), "
wrote: Funny thing about this. As one who focuses primarily on legacy equipment I own one KLH Table Radio. I own six (6) sets of AR speakers, all from the Teledyne days, all in active service from 3as through Athenas. I also own one-each of their amps, receivers and tuners. I own an Advent 500 SoundSpace control and a 100A dual-Dolby unit (matched to my Revox A77). I own a pair of ADS speakers out on loan. I own three pairs of Koss headphones, including their electrostatics. Other equipment in the inventory includes: Revox A77, A720 & 722, B225, B215, B290 Harman Kardon Citation 16, 17, 18 & 19, ST7, ST8, HK2000 Cassette. And several shelves of Dynaco tube and solid-state. Main speakers are Maggies. Multiple Sony Changers, 200 & 5 disc, all from thrift-shops. So apart from the Revox, Sony and the HK2000, everything is from the US and from 'back in the day'. Much of it via dumpster-dives, and purchasing repair-shop leavings as my eyes and ears have always been larger than my wallet. I did drive 1,200 miles round-trip for the Maggies, however, after a friend auditioned them in-situ. The price was that good. They are truly worth it. Peter Wieck Melrose Park, PA The Citation 16 is a brute of an amp. A speaker company I worked for used them to test our speaker designs. One night a guy broke into our factory and grabbed one of our 16s. The cops were chasing his car up a steep hill and the amp fell out of the passenger door and rolled down the hill. The outside damage was horrendous. We plugged it in and it worked! --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#16
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Power switch is erratic on receiver
"Chuck" wrote in message ... On Wed, 22 Mar 2017 12:19:14 -0700 (PDT), " wrote: Funny thing about this. As one who focuses primarily on legacy equipment I own one KLH Table Radio. I own six (6) sets of AR speakers, all from the Teledyne days, all in active service from 3as through Athenas. I also own one-each of their amps, receivers and tuners. I own an Advent 500 SoundSpace control and a 100A dual-Dolby unit (matched to my Revox A77). I own a pair of ADS speakers out on loan. I own three pairs of Koss headphones, including their electrostatics. Other equipment in the inventory includes: Revox A77, A720 & 722, B225, B215, B290 Harman Kardon Citation 16, 17, 18 & 19, ST7, ST8, HK2000 Cassette. And several shelves of Dynaco tube and solid-state. Main speakers are Maggies. Multiple Sony Changers, 200 & 5 disc, all from thrift-shops. So apart from the Revox, Sony and the HK2000, everything is from the US and from 'back in the day'. Much of it via dumpster-dives, and purchasing repair-shop leavings as my eyes and ears have always been larger than my wallet. I did drive 1,200 miles round-trip for the Maggies, however, after a friend auditioned them in-situ. The price was that good. They are truly worth it. Peter Wieck Melrose Park, PA The Citation 16 is a brute of an amp. A speaker company I worked for used them to test our speaker designs. One night a guy broke into our factory and grabbed one of our 16s. The cops were chasing his car up a steep hill and the amp fell out of the passenger door and rolled down the hill. The outside damage was horrendous. We plugged it in and it worked! Years ago some item of consumer electronics was reportedly rescued from the rubble after a gas explosion destroyed a block of flats, the fact it still worked was why it made the news. Too long ago to remember details, but it might have been a stereo amplifier - not a clue about make or model. |
#17
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Power switch is erratic on receiver
On Thursday, March 23, 2017 at 9:13:17 AM UTC-4, Chuck wrote:
The Citation 16 is a brute of an amp. A speaker company I worked for used them to test our speaker designs. One night a guy broke into our factory and grabbed one of our 16s. The cops were chasing his car up a steep hill and the amp fell out of the passenger door and rolled down the hill. The outside damage was horrendous. We plugged it in and it worked! The 19 is no slouch either. Same basic philosophy, two monoblocks in the same box sharing an on/off switch. I got both my examples for pocket change - but at different times - as they both displayed the same problem - intermittent left channel. Whatever else HK did and used with these amps, the input jacks were perhaps the cheapest they could fine, and I think that they may have specified crap directly as I could not find after-market devices of the same wretched quality. In any case, replaced the jacks and rewired the inputs and all has been well since. Since that time, I have repaired two other 19s with the same problem. Peter Wieck Melrose Park, PA |
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