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"pfjw@aol.com" <pfjw@aol.com>: Dec 19 05:46AM -0800 On Wednesday, December 14, 2016 at 10:22:03 AM UTC-5, pf...@aol.com wrote:   Update: The unit arrived with a thoroughly cooked power transformer - not one coil intact. Happily, I do not need an international transformer as a replacement, I can stick with 120V on the primary side. However, the rest of the unit, including the main amplifier boards test fine.   I have put out feelers to the usual suspects, Hammond et.al. as well as a couple of custom winders I have used in the past. Revox wants US$400 FOB Melrose Park. I think not.   I will report results.   Peter Wieck Melrose Park, PA

ohger1s@gmail.com: Dec 19 08:15AM -0800 > I will report results.   > Peter Wieck > Melrose Park, PA     If it's packed tightly, it could be a problem doing a retrofit if you don't mind not looking original. If it's got room, there are tons of options including using a XFR from a typical Japanese receiver (I might have some donors if you need one). You can split it up by putting in a trans for the power amp and a smaller one for the low voltage control voltages.   Transformer failures are so uncommon these days in big ampifiers. I have a 70s Heathkit AR1500 with a bad transformer. Pretty sure it's the only one I've ever seen in a relatively modern stereo system.

"pfjw@aol.com" <pfjw@aol.com>: Dec 19 12:20PM -0800 > If it's packed tightly, it could be a problem doing a retrofit if you don't mind not looking original. If it's got room, there are tons of options including using a XFR from a typical Japanese receiver (I might have some donors if you need one). You can split it up by putting in a trans for the power amp and a smaller one for the low voltage control voltages. >>SNIPPAGE<<   I have a good deal of room. I need four (4) secondary windings.   ftp://ftp.studer.ch/Public/Products/Revox/Revox_A722/Revox_A722_Diagr.pdf   Per the schematic. 26V, 24V, and two @ 63V. I DO NOT need more than one primary voltage (120V). If you do have a transformer that has those secondaries, I am interested at any reasonable price. I should have enough room, but I can also send dimensions if needed.   I suspect that the failure was due to someone putting in a massively over-large fuse as the burn extends all the way to the MV switch.   Thanks in advance!   Peter Wieck Melrose Park, PA

Phil Allison <pallison49@gmail.com>: Dec 19 12:34PM -0800 > that has those secondaries, I am interested at any reasonable > price. I should have enough room, but I can also send dimensions > if needed.   ** I see a triac "soft start" circuit hiding in there.   > I suspect that the failure was due to someone putting in a > massively over-large fuse as the burn extends all the way to the MV switch.   ** Very likely the voltage selector was set wrongly for use in Europe.   That triac may well be cooked too.     ..... Phil

"pfjw@aol.com" <pfjw@aol.com>: Dec 19 12:57PM -0800 On Monday, December 19, 2016 at 3:34:56 PM UTC-5, Phil Allison wrote:   > > massively over-large fuse as the burn extends all the way to the MV switch.   > ** Very likely the voltage selector was set wrongly for use in Europe.   > That triac may well be cooked too.   Assuming I find a suitable power-transformer, I will behave as if the entire power-supply from the rectifier board and beyond is cooked. Happily, most of the interior parts are of common types and voltages such that replacements and appropriate upgrades will be simple and not unusually costly. And despite being of Swiss design, Revox was not big on relabeled, proprietary parts on this amp.   When I received it (from Luxembourg), the MV switch was set to 240V. For what that is worth.   My existing very well behaved unit will be my comparison device if I can get it away from my granddaughter long enough.   Peter Wieck Melrose Park, PA

ohger1s@gmail.com: Dec 19 04:56PM -0800 > Thanks in advance!   > Peter Wieck > Melrose Park, PA   What's your time frame Peter? I am way above the top of my heinie with problems this week. Next week should be much easier for me.   I'll dig through my pile of yet to be scrapped stereo receivers and see what I have that will work. If I have something you can use, it's yours for the asking. It will do my heart good to see someone have use out of stuff that's been under foot for too long a time.

Phil Allison <pallison49@gmail.com>: Dec 19 10:11PM -0800 Phil Allison wrote:     > > ftp://ftp.studer.ch/Public/Products/Revox/Revox_A722/Revox_A722_Diagr.pdf   > ** I see a triac "soft start" circuit hiding in there.   ** It's really a remote on/off switch.     BTW:   What the heck are 82kohm resistors R1 and R2 doing in the power amp circuit ?   Even if they are 1% precision types, they can only creates a DC offset that is not desirable.     .... Phil

jurb6006@gmail.com: Dec 20 12:31AM -0800 >"What the heck are 82kohm resistors R1 and R2 doing in the power amp circuit ?   Even if they are 1% precision types, they can only creates a DC offset that is not desirable."   If the open loop gain is high enough it doesn't matter. Plus they got R4 in there which should bias the thing.   Possibly it is a method to keep DC offset from happening with highly non-sinosodial waves with extreme second harmonic distortion (such as the human voice) so that when it loaded one side of the power supply the imbalance would cancel out.   Revox is a weird company like that. I got the print of an FM tuner I can't even follow. They got more transistors in there than, well, anything. Ceramic filters all over the place n shit. Seriously ridiculous. And I mean to the point where I consider it severely overdesigned. On FM they transmit up to 15 KHz, it is not worth ten grand to receive. But this thing by golly can receive, I am sure of that. I'll have to see if I can find the model number, the print will make you drink. I can imagine it on paper, each of a ton of pages would be bigger than almost any desk, and some rooms.   I am not saying their stuff is not good, I just think they go too far sometimes.   You need two supplies for an amp, a low and a high. If you want, have a boosted supply like Pioneer et alii did years ago to run the drivers and smooth out the linearity when you got to the rails. That's three. This amp does not do that.   The only other thing those 82Ks might do it stabilise it during power up and power down. Remember the discussion about the QSC circuit with no center tap on the transformer ? Well they have to manage that DC from power up till power down. But this amp is not like that.   Really, those 82Ks are working into an 18K, so just how much can they do ?   Weird company, engineers probably get better drugs than anyone.   My best guess at the moment.

Phil Allison <pallison49@gmail.com>: Dec 20 03:29AM -0800 > Even if they are 1% precision types, they can only creates a DC >> offset that is not desirable."   > If the open loop gain is high enough it doesn't matter.   ** You really need to take MORE drugs.   Cos the ones you are taking now are not strong enough.   You still have a tenuous grasp on reality - but only just.       > Plus they got R4 in there which should bias the thing.   ** Posts the math anytime, in the next billion years, fuckhead.     > Really, those 82Ks are working into an 18K, so just how much can they do ?   ** Plenty - you fucking tenth witted prick.     > Weird company, engineers probably get better drugs than anyone.     ** ROTFL - says it all 'really.       .... Phil

"pfjw@aol.com" <pfjw@aol.com>: Dec 20 04:22AM -0800 > What's your time frame Peter? I am way above the top of my heinie with problems this week. Next week should be much easier for me.   > I'll dig through my pile of yet to be scrapped stereo receivers and see what I have that will work. If I have something you can use, it's yours for the asking. It will do my heart good to see someone have use out of stuff that's been under foot for too long a time.   I have enough projects in the queue such that June, 2022 would be OK. So, no rush whatsoever. And your efforts are much appreciated!   Take care!   Peter Wieck Melrose Park, PA

Bruce Esquibel <bje@ripco.com>: Dec 20 12:40PM > primary voltage (120V). If you do have a transformer that has those > secondaries, I am interested at any reasonable price. I should have enough > room, but I can also send dimensions if needed.   Maybe I'm getting dense with old age but you said ALL the windings are open? Both primary and secondary or just the multiple ones on the primary side?   Unless that thing caught fire and cooked for a while, I really can't see how those secondaries opened, if that is the case.   Two observational things, unless my eyesight is failing, those two secondaries are 53V not 63 and I don't see any indication what the current rating is.   It's one thing looking for a transformer with 53V @ 2A secondaries and one that is 53V @ 10A.   -bruce bje@ripco.com

"pfjw@aol.com" <pfjw@aol.com>: Dec 20 04:53AM -0800 On Tuesday, December 20, 2016 at 7:40:25 AM UTC-5, Bruce Esquibel wrote: > that is 53V @ 10A.   > -bruce > bje@ripco.com   Correct - 53VAC - I linked the clear schematic, while still looking at the blurry one.   I have come to find out from further discussions (all pleasant) with the seller that his source left it on overnight with a 10A automotive-type fuse in it and found it dead the next morning.   So, yes, 'cooked for a while' about covers it. No single winding is intact. Some are open, some are dead-shorted to each other and internally. The clear plastic wrap around the transformer is also mostly melted.   I paid little enough that I am sure I could recover everything, and more, in parting the remaining bits out. But I choose to accept the challenge and bring it back to life.   Peter Wieck Melrose Park, PA

pedro <me@privacy.net>: Dec 18 12:11PM +0800 On Mon, 12 Dec 2016 18:35:03 +0000 (UTC), root <NoEMail@home.org> wrote:   >It seems to me tht the charging circuits in the laptops >are smart enough to leave the chargers plugged in all >the time.   The *chargers* generally are. See Chris' reply for what the battery packs actually think of it.

boomer#6877250@none.com: Dec 20 01:25AM -0600 On Mon, 12 Dec 2016 10:38:29 -0800, John Robertson <spam@flippers.com> wrote:   >machines that are portable. I take mine home every night for example, >the rest are left wherever the staff last used them (cable locks).   >John :-#)#   I used to leave my Thinkpad T43 plugged in all the time. I used the computer maybe twice a month. I had used it in my car and it was working fine. I got home, plugged it in, and a gr days later I turned it on. The computer refused to turn on both with battery and AC power. The power module was working. I replaced the coin cell in the computer, it still did not turn on. I tested the hard drive in another computer, that was fine.   I thought about it, and recall we had a bad lightning storm on between the last time I used the computer and the time it refused to start. Apparently lightning fryed the motherboard.   I'm not equipped to repair this sort of thing, and being an older computer, I simply bought an identical model on ebay for about $40. I was able to use the power converter, battery, hard drive, and CD drive from the old computer in the new one. I did have to reinstall Windows XP though. Swapping the old HDD simply would not boot. I was told that has soemthing to do with the activation for XP. But I did not lose any data, all of that was fine on the old HDD, I just had to copy it to a flash drive (using another computer), and put it on the new laptop.   I wont be leaving my laptops plugged in all the time anymore. Especially during the seasons when we have electrical storms.

Tony Matt <tonym924@gmail.com>: Dec 19 10:52PM -0500 On 11/15/2016 12:09 PM, Jeff Liebermann wrote: > <http://boston.cbslocal.com/2016/10/22/transmission-issue-causes-outage-for-some-wbz-tv-viewers/> > No clue if it has been fixed, but judging by the lack of updates, > probably not.   The problem (defective transmission line to the upper master antenna on the CBS tower in Needham) was finally fully resolved this morning at 4:55AM. Lots more details at http://www.wgbh.org/about/Tower_and_Transmission_Signal_Issues.cfm (The CBS tower carries virtual channels 2, 4, 5, 8, 38, 44, and 48.)   Tony Matt

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 19 09:36PM "MJC" <gravity@mjcoon.plus.com> wrote in message news:MPG.32b6584bd1715df440@news.plus.net... > through the tube that leads the water down there so I can unblock by > giving it a wiggle. (A tacktick copied from "limber holes" in old boat > bilges!)   Reminds me of the "joggle pin" on 2-stroke motorcycle exhausts.   They had to make a hole in the silencer to drain unburned oil - that always got clogged by carbon deposits.   They put a split pin in the hole and spread it just enough to stop it falling inside.

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 17 09:52PM In the past week, my Dell monitor has developed the habit of doing a factory reset when the PC is booting up.   I wouldn't mind - but it gets it wrong and leaves the image shifted to the right.   Doing the factory reset manually corrects it, but its a hassle.   I'm wondering if I clicked something I shouldn't have, or the monitor is on its way out.   Its no biggie - I found the monitor in the first place, and since then scrounged a better one on Freegle, I'd just like to know what's going on.   Thanks.

mike <ham789@netzero.net>: Dec 17 05:53PM -0800 On 12/17/2016 1:52 PM, Benderthe.evilrobot wrote:   > Its no biggie - I found the monitor in the first place, and since then > scrounged a better one on Freegle, I'd just like to know what's going on.   > Thanks. it's almost always bad caps.

Michael Black <et472@ncf.ca>: Dec 17 11:41PM -0500

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 18 08:15PM "Michael Black" <et472@ncf.ca> wrote in message news:alpine.LNX.2.02.1612172340250.4773@darkstar.example.org... > reset, and display the Acer logo. I didnt' see any obviously bad > capacitors, but I changed the electrolytic ones at the output of the power > supply, and all was fine.   The last monitor that went down was bad caps - it was a more serious fault and I was basically just having a look before binning it. When I saw how simple it was, I did the repair.   There's one gathering dust in the corner, it has leakage on the front panel buttons - it develops a mind of its own in damp weather.   Need to be a bit more desperate before I could be bothered doing anything about it.

Jon Elson <jmelson@wustl.edu>: Dec 19 02:50PM -0600 Benderthe.evilrobot wrote:       > There's one gathering dust in the corner, it has leakage on the front > panel buttons - it develops a mind of its own in damp weather.   Yup, I had one that got a bit of drink spilled on it, and it corroded the board with the button switches. Whenever a button starts acting up, I remove the capacitor that is across the switch contacts and replace with a 100 pF cap, and clean the board well while the cap is removed. That seems to have fixed it. The button switches themselves seem to be fine.   Jon

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 19 08:55PM "Jon Elson" <jmelson@wustl.edu> wrote in message news:y-udnck6H-qg2sXFnZ2dnUU7-LHNnZ2d@giganews.com... > remove the capacitor that is across the switch contacts and replace with a > 100 pF cap, and clean the board well while the cap is removed. That seems > to have fixed it. The button switches themselves seem to be fine.   Mine doesn't have any switch capacitors, the board isn't corroded. I cleaned it and re-tinned all the button pins hoping it would dry them out - that didn't work.   Its a case of finding enough button switches to replace them all - and being bothered enough to do the job.

John Robertson <spam@flippers.com>: Dec 17 11:04AM -0800 On 2016/12/17 12:25 AM, N_Cook wrote: >> That corrected the problem. >> Mikek   > If you can thread wire through, I'd call those vias.   Some boards from the 70s used eyelets for their vias. They would be pressed into place, and over the years corrode enough to become intermittent.   Speaking of vias: the first coin operated video game - Computer Space - had a buss style motherboard (with sub-boards that held the logic) that was double-sided but they didn't plate the holes through so they put in tiny wires and soldered those top and bottom! I've also seen other early game boards that had plated through vias, but the holes were offset top/bottom and sometimes there was just a tiny bit of copper actually carrying the signal/current. Those were fun to troubleshoot when the copper corroded and several connections were lost.   John :-#)# -- (Please post followups or tech inquiries to the USENET 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."

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 18 10:14PM "N_Cook" <diverse@tcp.co.uk> wrote in message news:o316t8$f1i$1@dont-email.me... > integrity. > Perhaps with proper solder they made more robust joints but for RoHS times > ?   Eyelets are a PITA whatever solder you use.   A couple of monitor manufacturers used them for the flyback transformer pins to prevent dodgy soldering resulting in a fierce arc that burns a hole in the board.   Solder wetting round the edges of the eyelets was often worse than the dodgy soldering, and tended to cause the very problem it was supposed to prevent.

"Benderthe.evilrobot" <Benderthe.evilrobot@virginmedia.com>: Dec 18 08:32PM <dansabrservices@yahoo.com> wrote in message news:b9374c2a-b2aa-4961-bd29-bd0b6ce7570f@googlegroups.com... > There are a number of potential problems with this mostly due to age. > What is the problem? Also, where are you located? There are some of us > able to repair these, but a location is required.   The older VHS decks had a "lighthouse" bulb sticking up into the cassette for end sensors at each side to detect the clear leader at the ends of the tape - what it does when the bulb blows depends on the firmware. A common symptom is; won't come out of standby.   Later ones had an LED on the post, which almost never failed.   No idea whether the 8mm has one - but I'd look to see.

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