- Calculator button not working - 1 Update
- Diffferent techniques in troubleshooting - 7 Updates
- glass epoxy ? - 7 Updates
| John Heath <heathjohn2@gmail.com>: Jan 01 04:16AM -0800 On Thursday, December 31, 2015 at 9:41:28 AM UTC-5, Mark Zenier wrote: > where the subcarrier frequency could be from 20 kHz to 95 kHz. > Mark Zenier mzenier@eskimo.com > Googleproofaddress(account:mzenier provider:eskimo domain:com) Not only the carrier frequency but the data format and baud rates change so that each manufacturer can have there own unique remote. My TV a Hannspree has such an odd remote format that it is not listed in any of the standard general purpose remotes from what I could google. You would think that the industry would standardize remote controls to one format. Wifi with IP and MAC addresses works fine with just one standardized format. Remote controls could do the same with one format only and a data header of the serial number of the TV or stereo you want to talk to just like a MAC address. Then again it is hard to corral all the manufacturers to agree on one standard remote control. What is in it for them. |
| Jeff Liebermann <jeffl@cruzio.com>: Dec 31 09:14AM -0800 On Wed, 30 Dec 2015 16:10:40 -0800 (PST), John Heath >I would like to know if others have found this to be true. It's true, but only if you have a production line environment. During the late 1960's, I worked for a company that did warranty service on mostly consumer tape recorders. We would get the rejects and returns from the distributor. We had 4 people working the line. One to unbox and machine and organize the paperwork. One do to nothing but diagnostics. Me to tear it apart and do parts replacement, more testing, and reassembly. One more to do more paperwork, a final check, and reboxing. Anything that couldn't be fixed in 10-15 mins was put aside for later troubleshooting. Anything with more than 5 faults was deemed not worth repairing. It was quite efficient. As I vaguely recall, we could do about 4 to 10 machines per hour. What was interesting was the general lack of test equipment. As you noted, it takes far too much time to setup and probe. For audio, putting a finger on the base of a transistor and listening for hum worked well. To make it quick an easy, we had cardboard templates, with holes punched for all the common injection points with notes on what to expect. Head alignment and channel balancing was a different story. For that, we had a separate test fixture near final check. It had an audio generator and oscilloscope, but with a good ear, the scope wasn't really necessary. Unfortunately, this doubled the cycle time adding an additional 4 to 10 minutes. After you've worked on several hundred of exactly the same model tape recorder, you see patterns of failure. For example, if some component was inserted backwards on the first 10 or so units, it's a fair guess that the rest had the same problem. So, pre-emptive replacement was possible and worked well. Fast forward 30 years and I'm now doing marine radios and data transceivers. Over about a 10 year period, I was either involved or watched at least 5 different product test and QA systems. The one that worked best was visual inspection. I brought some of the assemblers into test to do the inspection. They couldn't read a resistor color code, but they could spot anything that had changed quite easily. The worst was a complex series of bench tests required by the customer, which involved a large pile of test equipment. I did a quick time-and-motion study and found that 30% of the test time was in setup, changing setup, and teardown. This would have been a great candidate for computer driven ATE (automagic test equipment) except that the PC of fashion at the time was an Apple III and RS Model II. We tried, and failed. So, we continued to use a pile of test equipment for test and troubleshooting. After about 3 years of this, some of the rotary switches on the HP equipment started to fail. Somewhat later, I had changed company and now had a product with sufficient quantity to justify ATE. The PC of fashion was the HP 9816 with an HP-IB(IEEE488) bus. It controlled a rack full of HP RF test equipment. I don't have time to go into detail on the setup. When it worked, it was great and could test, align(tune), print measurements, print reports, and live test amazingly quickly. When it didn't work, everything came to a grinding halt. I recall having 4 techs at idle while someone furiously drove to Fry's to buy a replacement part. I wanted to build a manually operated backup test line but management vetoed the idea. Getting all the equipment calibrated at the same time was tricky, but reduced downtime. ATE would have been a marginal failure had I not been able to "borrow" test equipment from the engineering dept. However, that was production test, not troubleshooting. When the manual or ATE test line declared something worthy of troubleshooting, it was NOT done while there were units waiting to be tested. If the products were cheap enough, they could just be "remanufactured" which means tear them apart down to the board level, run them back through board test, and build a "new" unit. This worked well with radios that had plugin cards. Eventually, there was a backlog of boards to be troubleshot. Usually between production runs and contracts, someone would decide that it's time to clean up the backlog. However, instead of having the test techs do the troubleshooting, the engineer who designed the radio would be sentence to overtime diagnosing the boards. Yeah, that was usually me. Unless the problem was trivial, I would only tag the likely parts, borrow someone that could do the soldering, retest the board, and send it on to production test. This worked well when we needed 25 identical board immediately, and was a total waste of time for 5 or less boards that took too long to setup. Today, much of what I see is ATE run by techs that only know how to push the buttons. Troubleshooting is done partly with BITE (built in test equipment). Parts replacement and soldering is outsourced to a contractor, specialty shop, or refurbisher. In short, there's nobody on the production line that knows which end of the soldering iron to grab, much less how the product actually works. The rule is that production must continue unimpeded by any form of troubleshooting or repair. If there is any troubleshooting, it's to fix the production line and ATE, not the actual product. Might as well say something about bugs and fixes. With todays fairly short product lives (typically about 6 months), it's not uncommon for a company to have 3 or 4 generations of replacement products in development at the same time. If something is found lacking or defective in the current product, it is cheaper and easier to simply wait for the next model to appear in production, and replace it with a later version. What this means is that NOTHING gets fixed in production, even when it's a known problem, easy fix, or major enhancement. If you see products with known design flaws that continue to be manufactured with the flaws, you now know why. <http://www.designnews.com/archives.asp?section_id=1367> Of course, there will still be independent repair shops (like mine) that fix things one at a time. They're a dying breed mostly because of the declining cost of modern electronics. As the retail price of new hardware declines, the amount of money that a customer is willing to pay for a repair also declines. As a rule-of-thumb, most customers will buy a new replacment instead of repairing something when the repair cost exceeds 50% of the replacement cost. So, if someone drags in an out of warranty laptop that cost them $500 about 3 years ago, my maximum bill (parts+labor) cannot exceed $250. Assuming no parts were replaced, that 3.3 hrs at $75/hr. The number of things I can fix in under 3.3 hrs is rapidly shrinking. For example, I have an APC XS1300 UPS on the bench that can be purchased new for about $125. In order to replace one lousy bulging electrolytic capacitor, I've already burned 2 hrs and I'm not done. Can I bill the customer $150 to fix a $125 UPS? Nope. So, the question isn't as much how to troubleshoot, but whether it's worth you time troubleshooting in the first place. Happy end of the tax year. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| "(PeteCresswell)" <x@y.Invalid>: Dec 31 01:46PM -0500 Per Jeff Liebermann: >worked well. To make it quick an easy, we had cardboard templates, >with holes punched for all the common injection points with notes on >what to expect. I "repaired" early digital-type equipment in the Air Force. Quotes because it turned out that all we did was find the failed circuit boards and replace them - leaving the actual repair work on the boards to the old-timers. We were told "Follow your nose".... and that proved to be the way almost all of the time.... you could locate the board with the failed component by smell and then visually verify after the board was pulled. I don't suppose that monkeys could be trained to do that.... but I am pretty sure than anybody with a room-temperature IQ could.... Six months of technical training at taxpayer expense down the drain.... Oh well.... -) -- Pete Cresswell |
| John Heath <heathjohn2@gmail.com>: Dec 31 12:14PM -0800 On Thursday, December 31, 2015 at 12:14:59 PM UTC-5, Jeff Liebermann wrote: > 150 Felker St #D http://www.LearnByDestroying.com > Santa Cruz CA 95060 http://802.11junk.com > Skype: JeffLiebermann AE6KS 831-336-2558 Sounds like you touched a lot of bases in the service life. I took a similar path ending up self employed for about the last 25 years. It has changed so much from the old days walking around with a tube caddy cleaning TV tuners. I now walk around with a laptop pinging IP addresses. How did that happen? I think the writing is on the wall. How many shoe repair and watch repair shops do you see. The electronic repair tech could meet the same fate. Just the other day I saw a flat screen monitor sitting in a garbage bin. To see the rain falling on it was too much so I took it inside. When I plugged it in everything worked and it had a VGA plus DVI input! What was that doing in the garbage. My only guess is someone wanted a wider flatter monitor so he or she tossed it out. I am typing on that monitor as we speak. How can one make a living in service with this going on. It is so bad that I have to work on 50,000 dollar LED displays boards. They will still fix those at that price. Just about everything else is disposable. However I have no regrets as electronics has been an existing ride with technology changing so fast that there is never a dull moment. |
| John Robertson <spam@flippers.com>: Dec 31 12:28PM -0800 On 12/31/2015 12:14 PM, John Heath wrote: >> Santa Cruz CA 95060 http://802.11junk.com >> Skype: JeffLiebermann AE6KS 831-336-2558 > Sounds like you touched a lot of bases in the service life. I took a similar path ending up self employed for about the last 25 years. It has changed so much from the old days walking around with a tube caddy cleaning TV tuners. I now walk around with a laptop pinging IP addresses. How did that happen? I think the writing is on the wall. How many shoe repair and watch repair shops do you see. The electronic repair tech could meet the same fate. Just the other day I saw a flat screen monitor sitting in a garbage bin. To see the rain falling on it was too much so I took it inside. When I plugged it in everything worked and it had a VGA plus DVI input! What was that doing in the garbage. My only guess is someone wanted a wider flatter monitor so he or she tossed it out. I am typing on that monitor as we speak. How can one make a living in service with this going on. It is so bad that I have to work on 50,000 dollar LED displays boards. They will still fix those at that price. Just abou t everything else is disposable. However I have no regrets as electronics has been an existing ride with technology changing so fast that there is never a dull moment. There is always arcade game repair. There is enough interest in that that most cities need a few people who do house calls. 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." |
| Jeff Liebermann <jeffl@cruzio.com>: Dec 31 04:59PM -0800 On Thu, 31 Dec 2015 13:46:01 -0500, "(PeteCresswell)" <x@y.Invalid> wrote: >Quotes because it turned out that all we did was find the failed circuit >boards and replace them - leaving the actual repair work on the boards >to the old-timers. In my checkered past, I once helped design two direction finders for the USCG AN/SRD-21 and 22. After shipping a fair number of these radios, I was given a tour of the local repair facility on Treasure Island in SF Bay. Sitting pilled in one corner was about 50 radios, in various stages of cannibalization. So much for spare parts. >We were told "Follow your nose".... and that proved to be the way almost >all of the time.... you could locate the board with the failed component >by smell and then visually verify after the board was pulled. Yeah, I do the same. I would prefer an FLIR infrared imager, but the nose will do for now. I also have a NIKKEN #1394 "air wellness air quality monitor". <http://802.11junk.com/jeffl/crud/Nikken-AQM.jpg> It's a nephelmometer which uses light scattering to detect airborne dust particles. <http://en.wikipedia.org/wiki/Nephelometer> Overkill: <http://www.esrl.noaa.gov/gmd/aero/instrumentation/neph_desc.html> It's been useful for finding what is burning in the office and locating the component producing the smoke. I've also used it to chase down the source of a white dust in a customers air ducts. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| Phil Allison <pallison49@gmail.com>: Jan 01 12:05AM -0800 John Robertson wrote: > chatting with Bob Parker (Dick Smith K-7204 kits in those days). Great > ESR meter that works in circuit for roughly values between 4ufd to about > 1000ufd. ** I find Bob's ESR meter useful with electro caps anywhere from 1uF to over 15,000uF. It also checks the ESR of tantalum electros. film caps from about 0.47uF upwards - for shorts and opens. Another use is with batteries, particularly Lithium button cells plus any type of AA, AA and 9V battery. As with caps, known good examples are your reference and ESR readings rise as the cell goes flat. A 20x3mm Lithium reads about 10 ohms when new rising to 100 ohms or more at end of life. ... Phil |
| John Heath <heathjohn2@gmail.com>: Jan 01 12:23AM -0800 On Thursday, December 31, 2015 at 3:28:53 PM UTC-5, John Robertson wrote: > (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) > www.flippers.com > "Old pinballers never die, they just flip out." I noted you are from Vancouver. I grew up there until about 14 then Montreal and now Toronto. Fond memories of biking down to Kitsilano beach. |
| Fred McKenzie <fmmck@aol.com>: Dec 31 11:49AM -0500 In article <ed08d40b-16f6-4438-8fac-4f41eb383840@googlegroups.com>, > recommend a glass epoxy for cracked halogen light covers ? I think the temperature may be too high for epoxy. If the covers are plastic, perhaps a solvent can be found that will "weld" the pieces together. What about fiberglass tape? Fred |
| Jeff Liebermann <jeffl@cruzio.com>: Dec 31 09:17AM -0800 >recommend a glass epoxy for cracked halogen light covers ? No. Halogens run very hot and G10/FR4 will scorch or crumble. Try sheet aluminum roof flashing. Paint it glossy white to reflect the heat. See examples in Luxo and Ledu desk lamps and overhead track lighting. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| Michael Black <et472@ncf.ca>: Dec 31 03:22PM -0500 |
| whit3rd <whit3rd@gmail.com>: Dec 31 01:04PM -0800 > recommend a glass epoxy for cracked halogen light covers ? Halogen lights emit significant UV light. I think the cover glass for them is UV-absorbing, and you don't want to use just any random glass. |
| avagadro7@gmail.com: Dec 31 03:49PM -0800 > recommend a glass epoxy for cracked halogen light covers ? uh the bulb is a small incandescent of flashlight bulb size running on 12 volts. There is a halogen assembly with glass missing I'm looking at trying a temperature analysis. The repair field is not in epoxy. Locktite suggests 350F for $24 then searching thru Google I remembered furnace cements leading to silicone furnace gasket cements leading to http://shop.advanceautoparts.com/p/permatex-sensor-safe-high-temp-rtv-silicone-gasket-3-oz-81422/7160173-P?searchTerm=hi+temp+silicone+sealer also 'flexible furnace cements' probabbbly paintable with a temp sealer both meant for metallic expansions not brick so the repair is possible. |
| Jeff Liebermann <jeffl@cruzio.com>: Dec 31 05:04PM -0800 On Thu, 31 Dec 2015 09:17:40 -0800, Jeff Liebermann <jeffl@cruzio.com> wrote: >sheet aluminum roof flashing. Paint it glossy white to reflect the >heat. See examples in Luxo and Ledu desk lamps and overhead track >lighting. Ummm... by "light cover" do you mean a lamp shade, luminaire, lens, or glass plate as used these fire hazards? <https://www.google.com/search?tbm=isch&q=halogen+pole+lamp> I thought you meant the thing (luminaire) that covers the light. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
| isw <isw@witzend.com>: Dec 31 07:54PM -0800 In article <ed08d40b-16f6-4438-8fac-4f41eb383840@googlegroups.com>, > recommend a glass epoxy for cracked halogen light covers ? If it's really glass, sodium silicate (a.k.a. water glass or egg preserver) might do the trick. Isaac |
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