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"Gareth Magennis" <sound.service@btconnect.com>: Dec 16 02:29PM Not come accross this sort of thing before but:   Customer brought in a Bose L1 Model 2 system - he's broken the slide out leg mechanism, and the legs will no longer deploy - they are locked together and will not move.   Now the only way to get to 4 of the screws to dismantle the unit is to slide out the legs, as the screws are hidden by them when they are stowed. So the unit cannot be dimantled to fix the mechanism.   Page 41 of the Service Manual shows the procedure.   http://elektrotanya.com/bose_l1_ii_system.pdf/download.html       Blimey.

Mike <news@mjcoon.plus.com>: Dec 16 09:23AM -0600 On Tue, 16 Dec 2014 14:29:33 +0000, Gareth Magennis wrote:     > Page 41 of the Service Manual shows the procedure.   > http://elektrotanya.com/bose_l1_ii_system.pdf/download.html   > Blimey.   Maybe this is Bose as in Higgs Boson, and can only be tackled in a parallel universe?   Mike.

N_Cook <diverse@tcp.co.uk>: Dec 16 03:20PM In poundland shops at the moment "party" scarves, black and silver thread or grey and silver thread, ignore the purple and silver. One will do 2 dual 12 inch combos. The one in front of me a Fender that a now ex-cat used as a scratching pad. Left tatty original in place, after removing the (surprisingly metal, looked plastic) Fender logo and screwing back over the half a scarf , slightly stretched over the frame and held with a few drawing pins (not pushpins) . As the scarf material is very open weave, just leave the corners uncut and the velcro still acts through it. Looks a treat, black and silver, just less likely to survive a snagging by cat or whatevever, as steadfastly as the original.

Tim Schwartz <tim@bristolnj.com>: Dec 16 10:08AM -0500 Hello,   Anyone have a service manual, or at least alignment instructions for one of these? It's an underwhelming small receiver, but the owner really likes it, and I'd like to do a decent alignment of it. I'd be happy to buy the manual, or pay for photocopies.   Thanks! Tim Bristol Electronics

jurb6006@gmail.com: Dec 15 04:59PM -0800 >"One that comes to mind is that Ecler, that spawned the >original discussion about magnets on the relays. "   There are possible other protection schemes when the power amp is married to the speaker. First of all the engineer should know all about what the speaker can take.   Right now I am on a Berhinger B115 with the woofer shutting down at a very low level. There is no relay but it has enough of a protection circuit that it knows the woofer voice coil is shorted. I find that pretty rare but most of the audio I have worked on over the years was consumer. (usually they are open) It is a class D amp, so any overcurrent detection is most likely in the PS. I have not checked.   I also have a Yamaha EMX (something) powered mixer, a two channel wedge design. It actually uses a relay but that is the first I've seen of one at this place. They all seem to depend on fuses and the like. Like this decent Fender BXR or whatever, the dumbass put a 25 amp fuse in it when the fuse blew. One of the transistors blew its top clean off. Now it might become a tradein so I had to check the speaker, which we will use. It is good, but you know if the idiot had not turned it off soon enough it wouldn't be.   One of the problems with consumer audio is the sheer cheapness of it. They need a relay probably for the UL if the thing has any power, and if lower power need it so they don't have to replace woofers when their winpy ass output circuits inevitably fry out. I mean, somonabitch, I had a five channel Sony that backfed something in the protection and fried OTHER channels ! I forget now, but they forgot one fucking diode. I forgot the exact failure mode because I WANT to forget the exact failure mode.   In a way I almost want to say that speakers should protect themselves, but that leaves the problem of dangerous wiring in case of a failure. The UL would not be happy with that. In fact I bet they would flunk my Phase Linear 400-2 these days. Don't want to add to the legal staff...   I remember working for the (ugh) rental place. They rented (SFS) Fisher systems wiht a CA-270 (discrete) amplifier. It had a relay but not DC protect circuit. You could see the traces on the board for it, as well as a commutatiing power supply for the outputs. All removed. I guess the bean counters and lawyers decided the risk was worth it. They did have some pretty hefty woofers in the some of the speakers, and depended on the five or six amp line fuse to blow I think for protection.   You know, on a manufacturig level, it probably would not cost all that much for those few transistors and shit. Really, the commutators that would save the outputs, a few diodes and shit to detect DC at the output ? This is not expensive. Not when you buy millions of each of the things, and the board is already etched, and even DRILLED for those components.   Ever since the Dodge brothers sued Henry Ford for making a too good product costing them dividends, manufacturers are forced to be so fucking stingy, really. Few people realize that if a company has the wherewithall to move to China and is publicly traded, MUST do so if it will increase profits. This is not bullshit, if they do not, they could be accused of a conflict of interest of worse.   And that really sucks and what has fucked up this as well as many other industries.   And in the US, including medical. In fact I have a suspicion about that. In medical equipment, the reason a twevle cent transistor is fifty bucks is because that is whay pays the lawyers in this country.

Phil Allison <pallison49@gmail.com>: Dec 15 07:14PM -0800 > The UL would not be happy with that. In fact I bet they would flunk my Phase Linear 400-2 these days.       * I have a Phase 400 series 2 in the workshop, fully repaired but long ago abandoned by its owner.   FYI:   Those darn amps had to be the most DC failure prone of any model in common use - there were so many ways:   1. Output device failure followed by the opening of one DC rail fuse meant that BOTH channels went full rail DC, ie 78 volts.   Since the two DC fuses were common to both channels, a shorted output stage fed wrong polarity DC to the now open rail of the other channel and thence to the speaker via one of the four 1A catch diodes wired across the output transistor groups.   2. Resistor failure: there were four resistors on the PCB that were certain fail open in time, the 1.4kohm 5W ones feeding the 15V zeners for the op-amp rails and the 7.5kohms 2W ones for the bootstrap circuit in each channel.   Failure of either 1.4kohms ( which ran stinking hot) sent the op-amps crazy and BOTH channels full rail DC while failure of a 7.5kohm did the same to one channel. Both parts suffered internal corrosion induced by high DC voltage across them.   Output transistors were prone to fail because of the thermal pads under them - made of plain pink coloured silicone. These pads were thermal insulators and the TO3 devices ran up to 50 degress C above the temp they would if good old mica and white grease were used.   Oh, and there were no thermal cut outs fitted to the heatsinks as in all previous models.       .... Phil

jurb6006@gmail.com: Dec 15 11:36PM -0800 >"made of plain pink coloured silicone. "   Mine are not pink.   I agree about the thing being dangerous. the owner's manual says to put speaker fuses in, well why didn't they put in some sockets of they weren't going to do anything else ?   Hm, was speaker protection even out there back then ? that might be a subject of interest. Or not.   Yup, and I own one of those. I really like how it sounds, but it has the evil look of a speaker blower extraordinaire.   It has done in my tweeters and tore the rubber right of my one 500 watt rated car subwoofer. I mean it ripped the rubber right off the aluminum. Believe it or not, at lower levels it stil sounds OK, but the fact still remains I need a pair of woofers. I am due to get them in the next couple days but then I still got the tweeter problem. Either way, for regular house speakers, shit like the 400-2 is danggerous. there is more power out there but it is usually protected.   some of the best sounding amps have nothing. Those old GFAs. the fuvck made them ? Oh, Adcom. And the Ampzilla, though I did not like the fact that the outputs are arrainged in series. However they DID have an actual speaker fuse. I am not sure of what else, and you kow what ? I am not sure what kind of distortion people seek. Sound is available thatis so perfect now that all this old shit would be discarded. WOULD BE.   As long as they pay as they say...   What do youse people down under and in the English grip call a garage ? I don't mean here you get a car fixed, I mena where you go out to smoke and drink becaus the olady doesn't like it.   I mean, I cannot predict this. TYou call the hood of a car the bonnet. You ccall the trunk a boot. What am I to do here ? And don't gimme this shit about l;earning English, there is noone here to teach me.

jurb6006@gmail.com: Dec 15 11:39PM -0800 >"1. Output device failure followed by the opening of one DC rail fuse meant that >BOTH channels went full rail DC, ie 78 volts. "   Only ONE of them, I think the negative. and it was not full current. you owuld read that on a meter or whatever, but it was not putting out all the current it can.   Yes, they are bad in that respect. That is why I used MJ15024s in mine.

Phil Allison <pallison49@gmail.com>: Dec 16 03:38AM -0800 > >"1. Output device failure followed by the opening of one DC rail fuse meant that >BOTH channels went full rail DC, ie 78 volts. "   > Only ONE of them, I think the negative.     ** If one output transistor fails short ( ie suffers punch through ) - then it immediately causes similar failure of at least one other transistor on the opposite side. Then you have as hard short, rail to rail, that makes at least one DC fuse blow. > Yes, they are bad in that respect. That is why I used MJ15024s in mine.   ** Most PL400-2s had MJ15024s, later versions were "fully complimentary" with 024s and 025s. Maybe very early PL400-2s had PL909s - not sure.     ... Phil

John Robertson <spam@flippers.com>: Dec 15 11:17AM -0800 On 12/14/2014, 3:53 PM, William Sommerwerck wrote: > news:rtvr8aplg64qn33fgdj6f8v49uej97m19l@4ax.com... >> Looks like you are describing the lamp's fuse?   > I didn't know they had them. I assumed it was a sample defect.   I thought I recalled seeing something about there being a weak spot intentionally added to the internal leads in case the filament shorted inside the bulb...   Can't find anything in quick online searches though, and I don't have a line voltage light bulb design specs book.   John :-#(#   -- (Please post followups or tech inquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

"William Sommerwerck" <grizzledgeezer@comcast.net>: Dec 15 01:08PM -0800 "John Robertson" wrote in message news:QOednSgxFYRfrhLJnZ2dnUU7-V2dnZ2d@giganews.com... On 12/14/2014, 3:53 PM, William Sommerwerck wrote: > inside the bulb... > Can't find anything in quick online searches though, and I don't have > a line voltage light bulb design specs book.   Here you go. Scroll down to "Why burnout is sometimes so spectacular". (I'm awfully good at finding stuff.) This bulb obviously had a defective fuse. You learn something new every day.   http://donklipstein.com/bulb1.html

John Robertson <spam@flippers.com>: Dec 15 02:40PM -0800 On 12/15/2014, 1:08 PM, William Sommerwerck wrote: > (I'm awfully good at finding stuff.) This bulb obviously had a defective > fuse. You learn something new every day.   > http://donklipstein.com/bulb1.html   http://donklipstein.com/bulb1.html#wbs - for the lazy.   Thanks!   Gee, an Internet light bulb database, who'd have guessed (OK, I should have known better), and why didn't the search engines turn that up in my earlier searches?   John :-#)#   -- (Please post followups or tech inquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

"William Sommerwerck" <grizzledgeezer@comcast.net>: Dec 15 03:25PM -0800 "John Robertson" wrote in message news:zPydnVSczNff_hLJnZ2dnUU7-VudnZ2d@giganews.com...   > Gee, an Internet light bulb database, who'd have guessed > (OK, I should have known better), and why didn't the search > engines turn that up in my earlier searches?   I Googled "incandescent lamp internal fuse". It was #4, rising with a bullet.

John Robertson <spam@flippers.com>: Dec 15 11:05PM -0800 On 12/15/2014, 3:25 PM, William Sommerwerck wrote: >> engines turn that up in my earlier searches?   > I Googled "incandescent lamp internal fuse". It was #4, rising with a > bullet.   Hmm, I didn't use 'incandescent', but putting that in (I used just lamp) I found some interesting reading for "incandescent lamp lead fuse" - one from some retired electricians writing in 1922 about early shipboard lighting where fuses hadn't been considered...almost set the ship on fire!   Fourth down titled: Electric Fuses - Page 4 - Google Books Result   https://books.google.ca/books?id=8r-XrMvGm4YC&pg=PA4&lpg=PA4&dq=incandescent+lamp+lead+fuse&source=bl&ots=3cty9MSMHW&sig=qYmMtrc3__Z-dbQCbTYCSyDqcZo&hl=en&sa=X&ei=29ePVJC8Csu1ogSVzYDoDQ&ved=0CEIQ6AEwCA#v=onepage&q=incandescent%20lamp%20lead%20fuse&f=false   or a tiny custom URL:   http://tinyurl.com/IncandescentLampFuse   John :-#)# -- (Please post followups or tech inquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) www.flippers.com "Old pinballers never die, they just flip out."

Jeroni Paul <JERONI.PAUL@terra.es>: Dec 15 11:59AM -0800 Its purpose is probably to absorb the vibration and make the unit somewhat quieter and stop the disk from slipping when speed changes suddently.

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