sci.electronics.repair@googlegroups.com

Google Groups

N_Cook <diverse@tcp.co.uk>: Aug 12 07:21PM +0100 Hang on a bit , a quote on submarine cable manufacture "Two layers of coal tar-impregnated jute over the armor wires complete the cable structure."

"pfjw@aol.com" <pfjw@aol.com>: Aug 12 11:35AM -0700 On Friday, August 12, 2016 at 2:21:47 PM UTC-4, N_Cook wrote: > Hang on a bit , a quote on submarine cable manufacture > "Two layers of coal tar-impregnated jute over the armor wires complete > the cable structure."   Not much burns underwater. Jute resists seawater better than most other natural fibers. Coal tar, while vicious stuff (and one of the ingredients for Greek Fire), also does rather well under water, unlike asphalt.   Would this be the specification used by the Great Eastern? That is about the correct vintage...   Now, without reference to the NET, what is significant about the Great Eastern? There are masny things, but exclude cable-laying for this answer.   Peter Wieck Melrose Park, PA

N_Cook <diverse@tcp.co.uk>: Aug 13 01:58PM +0100 The Tx came out easy enough, as did the outer layer of paper, after warming with hot air, so cannot have been that cooked. Frame and wires to each other showed nothing to 30M on DVM-R or to 20G on megger. Enamel of outer 6.6V,6A winding looks fine, but blacker paper under that layer. No sign of any tar, looks as though it is beeswax? , looks like whatever the yellowish wax that was covered on those notoriously leaky waxed paper caps, its that which has carbonised to black tar-like material probably, and flowed out of the Tx. No cloth seen in lower layer either, seems paper and wax. Over about 2mm of ome of the wax/tar on the inside of the removed paper, got a Megger reading of 5G. I'm assuming a distributed "carbon resistor " over a large area (to distribute .5KW of heat) rather than shorted turns as at no point has there been any of that nasty magnetisation buzz of shorted turns. How to determine if the "resistor" is on the primary, nearest core so hottest, or the HT secondary winding?, unlikely the high amp windings. Nothing to loose placing the Tx on a tray in a low oven, but which orientation, as in normal use or the other way up and hope enough wax flows out. It would be nice to take some before and after ohms reading of something , if anyone has any ideas.? Leaves the possibility of near enough solid carbon at the main hotspot, that will not budge at all. You'd think after decades at this game you'd have seen all possible fault scenarios.

N_Cook <diverse@tcp.co.uk>: Aug 13 02:33PM +0100 I just thought , take R and L readings with a RLC meter, for the sections of primary (assuming same gauge of wire through the length) and 2 sections of HT secondary and they should be proportionate, R to L of each section. Then retake readings after heating. BTW I rechecked the Tx ,after removal, on variac

Micky <NONONObobbyburns1111@gmail.com>: Aug 12 02:51PM -0400 OT This is ot but I figure I have a better chance of getting a good answer here than most other places.   After only 4 days over 90 in Baltimore last summer, so far this summer we've had about 33 with more on the way.   And after 49 years with a convertible, in the last three or four years I've finally been willing to use the AC even when the temp is below 90 or 95 (I forget.)   So it seems to me that when the fan is on speed 1, the air coming out of the dash will be quite cold (and it is), but on speed 2, which is faster, it seems to me the air go through the evaporator faster and would have less time to cool off and it woudn 't be quite so cold, and on speed 3, I'd expect it to be noticeably not as cold. (I don't use speeds 4 or 5 because they make too much noise, but I could make tests if anyone wants me to.)   But in practice, they all seem to be the same temperature. How can that be? Is it just that I'm right but the difference is too small to sense?

root <NoEMail@home.org>: Aug 12 07:15PM > But in practice, they all seem to be the same temperature. How can > that be? Is it just that I'm right but the difference is too small > to sense?   One possible explanation is that the heat exchanger is able to equilibrate the air temperature at the different speeds you chose. This would mean the air passages within the heat exchanger are sufficiently long.

"pfjw@aol.com" <pfjw@aol.com>: Aug 12 12:50PM -0700 On Friday, August 12, 2016 at 3:15:21 PM UTC-4, root wrote:   > equilibrate the air temperature at the different speeds you > chose. This would mean the air passages within the heat exchanger > are sufficiently long.   Exactly this. most auto AC units have an evaporator sensor to help prevent the coil from freezing. At a higher fan speed, more refrigerant is permitted through the coil to maintain an even discharge temperature. I had one fail recently (under warranty), it takes about 30 minutes at 95F/70RH to freeze a coil to a block of ice if the refrigerant discharge is not regulated.   Peter Wieck Melrose Park, PA

jurb6006@gmail.com: Aug 12 04:28PM -0700 >"Exactly this. most auto AC units have an evaporator sensor to help >prevent the coil from freezing. At a higher fan speed, more >refrigerant is permitted through the coil to maintain an even >discharge temperature. I had one fail recently (under warranty), it >takes about 30 minutes at 95F/70RH to freeze a coil to a block of >ice if the refrigerant discharge is not regulated. "   They have apparently changed again then. All though the 1980s it was a cap tube/critical charge system. Cheap, compared to the old ones that had a real thermostatically controlled expansion valve and an accumulator.   The ones I saw simply worked on low side pressure. The lower the pressure, the lower the temperature. It also served the purpose of keeping the compressor from sucking in air in case of a low side leak. But of course most leaks are on the high side.   I haven't worked on alot of newer cars, but I do know they are doing alot of things to improve efficiency, like variable valve timing which is pretty expensive to implement. But so were roller lifters at one time. I am not sure how much they're getting out of the direct cylinder injection but if it raises the power to weight ratio that is a plus. Both of these things were unheard of in the 1970s.   It was said the AC takes about 12 HP in a car. People have told me also that the performance is off when they have the air on. Some cars had a switch to temporarily disengage the compressor at wide open throttle. Not sure if they still have that or just use the computer to do it.   Another reason they need some sort of regulation is that most cars run the compressor when you use the defrosters. It allows it to start clearing the window long before the car is warmed up. In the 1980s GMs at least you could hear the compressor kick in and out in the winter as if you are low on Freon, but it is because the temperature is so low. Obviously the heater core goes before the evaporator but if the engine is not warmed that means nothing.

Tim R <timothy42b@aol.com>: Aug 12 07:17PM -0700 I haven't checked lately, but the last time I looked an automotive air conditioner was about 3 tons capacity.   That will cool the average house.   But a car needs more, because of the solar gain from all the glass, and the fact that you have to cool it down in ten minutes rather than 24 hours.

jurb6006@gmail.com: Aug 13 01:32AM -0700 On Friday, August 12, 2016 at 9:17:43 PM UTC-5, Tim R wrote: > I haven't checked lately, but the last time I looked an automotive air conditioner was about 3 tons capacity.   That jibes, 36,000 BTU converts to 14.something HP. Makes sense as it would unload somewhat when the evaporator gets nice and cold and it is pulling cold air in from the cabin.   http://www.endmemo.com/sconvert/btu_hhp.php   > That will cool the average house.   Wish it would cool this one better, and actually this is bigger than three tons.   > But a car needs more, because of the solar gain from all the glass, and the fact that you have to cool it down in ten minutes rather than 24 hours.   I have to wait ten minutes ? No way.

dplatt@coop.radagast.org (Dave Platt): Aug 12 11:16AM -0700 In article <nokagk$u7p$2@gioia.aioe.org>, >terminals in my unit there's really nothing else I can check either on >the outside of the building or elsewhere (which should be Verizon's >responsibility).   "Laundry room" rings a bell with me.   In a house we rented some decades ago, we had problems with line noise on the phone, ring failures (the caller would hear a ring tone and then an immediate disconnect) and other problems.   The problem turned out to be laundry-related, in a way. The line came into the house in the kitchen, and was wired to one of the square four-terminal line blocks before running up the wall to the phone. This was located right next to the clothes washer.   It turned out that over the years, dirt and spiderwebs (and maybe some soap dust) had gotten into the connection block, and build up on the surfaces. When humidity was high (e.g. when we were doing laundry with hot water) and the surfaces were cold (e.g. winter) moist air would cause condensation inside the connection block, dampening the surface contamination and creating a current leakage path.   It was bad enough that when the phone would try to ring for an incoming call, enough current would flow to momentarily trigger the central office's "off hook" detector, and the call would be "answered"... and then drop out immediately.   The cure was straightforward: pop off the connection-block cover, dust it out, scrub everything with a soft brush and some denatured alcohol to remove the contaminants, dry thoroughly, close back up. Problem gone.   I once had a similar problem, in which house moisture condensing inside a Macintosh keyboard in a cold room would bridge the ADB "power button" signal lines enough to cause the Mac to power itself on. Cleaning and drying the PC board in that area, and then dabbing on a thin layer of fingernail polish as a "conformal coating" fixed the problem.   So, it might be worth checking your inside wiring and phones for any places where cross-wire current leakage might occur. Clean, dry, and if possible insulate against further contamination and moisture.

"Ron D." <Ron.Dozier@gmail.com>: Aug 12 10:21PM -0700 I totally agree with Dave's assessment. You really have no way of isolating your phones. Assume that the phones have a single demark point home-run point in your apartment, maybe you do.   Look at all of the jacks and clean them up. Look for signs of moisture.   if it happens again, check the laundry room. See how bad the "dew point" is.   Here http://protective.sherwin-williams.com/pdf/tools-charts-list/dew_point_calculation-chart_f.pdf is a Dew point chart. You have temperature, relative humidity and surface temperature.   Once you calculate the dewpoint, the surface temperature should be higher than this. The surface being the punch down block surface.   While your in that box, arrange your wires so they have "drip loops" on them. You don't want water(moisture) traveling along wires and getting the terminal area wet. Cleaning the area between your terminals should be sufficient for a while anyway if that's the problem.

buymobile.eracell@gmail.com: Aug 12 10:17PM -0700 On Tuesday, August 9, 2016 at 2:01:11 AM UTC+6, Jon Elson wrote: > have quite broadcast studio sound, it is way better than the analog PBX we > had before. I'm really happy with them.   > Jon   Thanx for suggesting , but for VOIP stuff I prefer to check this site they provide best deal for Wireless devices and accessories. https://www.buymobile.com.bd/

LINDA B <fusionist4@gmail.com>: Aug 12 08:06PM -0700 > This is not good. It does not sound like bad filters or anything easy like that. Sounds like a software problem, or, as I found recently a hidden problem in the CD drive screwing up the whole system. I work on Karaoke players and if the CD drive gets into a knipshit it can confuse the microprocessor.   > In those cases, unplugging can work, like it did for you.   > In this case I don't know what to tell you. Just watch for mechanical problems first and then for bad filters. That usually works the best these days.   Thank you for the advice, i'm new here not on the internet. I do try to be polite when asking for help. Anyway, my husband doesn't want me to try to fix it, opting to leave it running 24 hrs. a day. I work on things more complicated than his radio and usually fix them. I offered to fix it, so his problem now. Thank you all for your suggestions.

"Snuffy \"Hub Cap\" McKinney" <Snuffy-Hub-Cap@Livebait-McKinney.com>: Aug 12 01:40PM -0700 Sorry folks. Big disappointment here. I fell for the old "best shower in decades" trick.   "Snuffy "Hub Cap" McKinney" <Snuffy-Hub-Cap@Livebait-McKinney.com> wrote in message news:Wa2dncahda19KzHKnZ2dnUU7-LnNnZ2d@earthlink.com... Fellow tinkerers....this one is supposed to have twice as many as normal. The story is that the best time is after midnight, after the moon goes down. Best way is to lie flat on a lawn chair with a nice tall drink in one hand, face the northeast and look about 2/3 of the way up and try not to fall asleep.   http://www.npr.org/sections/thetwo-way/2016/08/10/489491194/this-years-perseid-meteor-shower-is-going-to-be-quite-a-show-heres-how-to-watch   Or watch the live stream.... http://www.ustream.tv/channel/nasa-msfc

mikhailovsky@gmail.com: Aug 12 11:47AM -0700 Hi folks,   I am looking for Spectraphysics DCR-11 electronics diagram. I have a manual with block diagram which helped me to figure out that the source of the laser malfunction is in switching high voltage power supply, but I hope to avoid reverse engineering it. If you have the diagram and are willing to share it with me, please let me know.

You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com.