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Chuck H. <chuck@dejanews.net>: Sep 19 09:16PM -0500 On Mon, 17 Sep 2018 11:30:08 -0700, dplatt@coop.radagast.org (Dave Platt) wrote:   >looks at a "standby" pushbutton... this is a low-level contact closure >and seems to be tied in with the main keyboard scanning logic. So, a >contaminated "standby" PC board / assembly might be at fault.   David, As you surmised, the problem was the power tact switch. I didn't check it because I heard a weird distortion while playing a cd the night before. So I thought the problem was a voltage inbalance causing the protection circuit to engage. The last unit I repaired was a dehumidifier where every tact switch was open so luckily I had the switch in stock. Years ago a high end Technics cassette deck came into the shop. Every tact switch was open so I asked the customer what environment the unit was used in. It was used in a room where metal was etched. The fumes ate away the tact switches' internals. Thanks for guiding me in the right direction.

jurb6006@gmail.com: Sep 19 11:27PM -0700 >"The last unit I repaired was a dehumidifier where every tact switch was open"   So dehumidifiers are fucking digital now ? What is next, bath towels ?   (it took me a while to think of something, can't use chairs, toilets, vacuum cleaners, lawnmowers, refrigerators, flashlights, toasters, sinks, bathtubs, ummm, what else can you use ?)

tabbypurr@gmail.com: Sep 20 03:08AM -0700 > >"The last unit I repaired was a > dehumidifier where every tact switch was open"   > So dehumidifiers are fucking digital now ? What is next, bath towels ?   electronically controlled units work much better than mechanical humidistats   > (it took me a while to think of something, can't use chairs, toilets, vacuum cleaners, lawnmowers, refrigerators, flashlights, toasters, sinks, bathtubs, ummm, what else can you use ?)   should I ask why you can't use any of those?     NT

Tim R <timothy42b@aol.com>: Sep 20 07:11AM -0700 On Wednesday, September 19, 2018 at 5:16:35 PM UTC-4, Chuck H. wrote: > David, > As you surmised, the problem was the power tact switch. I didn't check > it because   Even though I know better, I have screwed diagnosis many times by thinking I knew what the problem might be and going down the wrong path. It's almost irresistible sometimes.

John-Del <ohger1s@gmail.com>: Sep 20 07:21AM -0700 > > dehumidifier where every tact switch was open"   > > So dehumidifiers are fucking digital now ? What is next, bath towels ?   > electronically controlled units work much better than mechanical humidistats   If you need to keep humidity to within a fraction of a percent perhaps, but in my experience, electronic controls add complexity and complexity means trouble.   If this dehumidifier was used to keep someone's basement dry and sweet smelling, it would be far better off with a quality mechanical humidistat that kept the humidity within a few points either way. As it is, the poster mentioned that this needed tact switches, something a mechanical unit wouldn't have.

Chuck <ch@dejanews.net>: Sep 20 10:14AM -0500 On Thu, 20 Sep 2018 07:11:02 -0700 (PDT), Tim R <timothy42b@aol.com> wrote:   >> As you surmised, the problem was the power tact switch. I didn't check >> it because   >Even though I know better, I have screwed diagnosis many times by thinking I knew what the problem might be and going down the wrong path. It's almost irresistible sometimes. You bet. I spent 47 years repairing consumer , pro audio, television studio, video conferencing, and server equipment. Though retired, I shouldn't have slipped this much.

"jfeng@my-deja.com" <jfeng@my-deja.com>: Sep 20 06:31AM -0700 Here is an article from one of the electronics trade magazines on 18650 cells:   https://www.electronicdesign.com/power/standard-18650-li-ion-cell-isn-t-always-standard?NL=ED-001&Issue=ED-001_20180920_ED-001_284&sfvc4enews=42&cl=article_1_b&utm_rid=CPG05000000306689&utm_campaign=20055&utm_medium=email&elq2=d60026c895f74e0289ff9cc19fbc9ac3

rodrigorivas33@gmail.com: Sep 19 10:41AM -0700 I love old electronics and recently purchase a Panasonic TR-4CT5, it powers on and volume text is normally bright. Just have issues when I plug line in. Brightness of the input is fine for a minute then fades to super dark.   Volume label stays at right brightness so I figured it;s not the CRT or brightness, feel it's a capacitor somewhere or something to do with the video input as on UHF noise is OK and doesn't fade dark.   I scoured google for a manual or service manual but I could not find anything. Any help or guidance would be appreciated as I think it's an electronic I really want to conserve.   Thanks guys

John-Del <ohger1s@gmail.com>: Sep 19 11:18AM -0700 > I scoured google for a manual or service manual but I could not find anything. > Any help or guidance would be appreciated as I think it's an electronic I really want to conserve.   > Thanks guys     Yes, it's always a capacitor...   Get the numbers off any IC you can find and get the datasheets off the web. The datasheets will tell you what they are and what the inputs and outputs are as well as what voltages should be on the Vcc. Unless it's mostly discrete transistors, datasheets are almost as good as a schematic.   With some searching, you may be able to identify another Panasonic model that might be virtually identical from a chassis standpoint, and you might find the schematic to that.

tabbypurr@gmail.com: Sep 19 01:33PM -0700 > I scoured google for a manual or service manual but I could not find anything. > Any help or guidance would be appreciated as I think it's an electronic I really want to conserve.   > Thanks guys   can't work out what you mean at several places. It doesn't sound like a bad electrolytic capacitor, they don't work ok for a bit then not.     NT

tabbypurr@gmail.com: Sep 19 01:34PM -0700 > > Thanks guys   > can't work out what you mean at several places. It doesn't sound like a bad electrolytic capacitor, they don't work ok for a bit then not.   > NT   I'd probably start by prodding the pcb with a plastic stick, see if one spot is sensitive.     NT

John-Del <ohger1s@gmail.com>: Sep 19 06:39PM -0700 > > Any help or guidance would be appreciated as I think it's an electronic I really want to conserve.   > > Thanks guys   > can't work out what you mean at several places.   I think he means that the only source that goes dark after a minute is the video input. The UHF snow and the on screen display maintain normal brightness at all times, so he correctly assumed the CRT as well as the HV and CRT circuitry are OK.   If it goes dark after running normally for a minute or so, I'd try cheating by applying freeze spray. Might turn up a gimpy IC or transistor in a couple of minutes.   If it's not thermally sensitive, I would check to see if the composite switching is done by a mechanical select switch or by logic control. A schematic would be a big help but on a b&w TV there's not much to them. If it's got ICs, that's half the battle as datasheets provide a partial schematic.

OGER <OGER@NOWHERE.COM>: Sep 19 06:38PM -0700 Need the schematic for   4VWIN Wireless Home Security Driveway Alarm https://www.amazon.com/4VWIN-Wireless-Security-Driveway-Receiver/dp/B01JRASCDU/ref=sr_1_129?ie=UTF8&qid=1537407005&sr=8-129&keywords=garage+door+monitor   or Harbor Freight Home Security Driveway Alarm https://www.harborfreight.com/wireless-security-alert-system-62447.html   or ? whatever name it is sold under.   I want to modify it for my special application.

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