Received: from PCH.mit.edu (18.7.21.50) by mail.efplus.com (192.168.0.8) with Microsoft SMTP Server (TLS) id 8.3.485.1; Thu, 7 May 2020 22:18:02 -0700 Received: from PCH.MIT.EDU (localhost.localdomain [127.0.0.1]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 0484upI1015818; Fri, 8 May 2020 00:57:21 -0400 Received: from outgoing-exchange-7.mit.edu (OUTGOING-EXCHANGE-7.MIT.EDU [18.9.28.58]) by PCH.mit.edu (8.14.7/8.12.8) with ESMTP id 0484uoQf015815 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 8 May 2020 00:56:50 -0400 Received: from oc11exedge1.exchange.mit.edu (OC11EXEDGE1.EXCHANGE.MIT.EDU [18.9.3.17]) by outgoing-exchange-7.mit.edu (8.14.7/8.12.4) with ESMTP id 0484uEge001892 for ; Fri, 8 May 2020 00:56:15 -0400 Received: from w92expo8.exchange.mit.edu (18.7.74.62) by oc11exedge1.exchange.mit.edu (18.9.3.17) with Microsoft SMTP Server (TLS) id 15.0.1293.2; Fri, 8 May 2020 00:56:06 -0400 Received: from oc11exhyb8.exchange.mit.edu (18.9.1.113) by w92expo8.exchange.mit.edu (18.7.74.62) with Microsoft SMTP Server (TLS) id 15.0.1365.1; Fri, 8 May 2020 00:56:49 -0400 Received: from NAM12-DM6-obe.outbound.protection.outlook.com (104.47.59.177) by oc11exhyb8.exchange.mit.edu (18.9.1.113) with Microsoft SMTP Server (TLS) id 15.0.1395.4 via Frontend Transport; Fri, 8 May 2020 00:56:49 -0400 Received: from MWHPR04CA0066.namprd04.prod.outlook.com (2603:10b6:300:6c::28) by BYAPR01MB3846.prod.exchangelabs.com (2603:10b6:a02:82::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2958.20; Fri, 8 May 2020 04:56:48 +0000 Received: from CO1NAM03FT044.eop-NAM03.prod.protection.outlook.com (2603:10b6:300:6c:cafe::d9) by MWHPR04CA0066.outlook.office365.com (2603:10b6:300:6c::28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2979.26 via Frontend Transport; Fri, 8 May 2020 04:56:48 +0000 Received: from mail-pf1-f169.google.com (209.85.210.169) by CO1NAM03FT044.mail.protection.outlook.com (10.152.81.108) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2979.27 via Frontend Transport; Fri, 8 May 2020 04:56:47 +0000 Received: by mail-pf1-f169.google.com with SMTP id 18so323113pfx.6 for ; Thu, 07 May 2020 21:56:47 -0700 (PDT) Received: from esk ([1.129.198.112]) by smtp.gmail.com with ESMTPSA id n5sm436826pgg.31.2020.05.07.21.56.44 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 07 May 2020 21:56:44 -0700 (PDT) Received: from james by esk with local (Exim 4.90_1) (envelope-from ) id 1jWv3v-000320-Bc; Fri, 08 May 2020 14:56:39 +1000 From: James Cameron To: Microcontroller discussion list - Public. Sender: "piclist-bounces@mit.edu" Date: Thu, 7 May 2020 21:56:39 -0700 Subject: Re: [EE] Thermally Protected Motor Thread-Topic: [EE] Thermally Protected Motor Thread-Index: AdYk+Ay2BwxLcBrEQ4G7PvJ7vOhp2A== Message-ID: <20200508045639.GA10870@laptop.org> References: <20200501215653.GD16970@laptop.org> <6E7CCD09-A0DE-4248-A733-06CADE1BCEDA@standingwave.org> <20200502001948.GG16970@laptop.org> List-Help: List-Subscribe: , List-Unsubscribe: , In-Reply-To: <20200502001948.GG16970@laptop.org> Reply-To: Microcontroller discussion list - Public. Accept-Language: en-US X-MS-Exchange-Organization-AuthAs: Anonymous X-MS-Exchange-Organization-AuthSource: TS500.efplus4.local X-MS-Has-Attach: X-Auto-Response-Suppress: All X-MS-Exchange-Organization-SenderIdResult: Pass X-MS-Exchange-Organization-PRD: mit.edu X-MS-TNEF-Correlator: received-spf: Pass (protection.outlook.com: domain of laptop.org designates 209.85.210.169 as permitted sender) receiver=protection.outlook.com; client-ip=209.85.210.169; helo=mail-pf1-f169.google.com; dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=laptop-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=k/DjD8S8iZ7DvapUNMzw4sVup2s7T8C77S9YWzFYxZg=; b=postVb2vz22UeCwuX8oQoVxKbt37y3QuPiNTWTvyKCfLYEvqcRdmBFd0FmQBkAU9gV 2A4ic8PIwDSaZu2Lici/LKujlLvaMEfp75kFqhyyg2JOJiNLgwzvWqC87mfZS2a1WflE sAJ8m5k+DkmgibBeOtIxi70YD+5qyYxw8qUDXvxdSw99j0akw0S29LddMQbWfH5qzO3F I1Z29z/qGj8I+LMN4/jD1h3CLhBwMDUA+E4IaXjNKP47vBd7LMb6yDybcq/4IyYqMB1Z 3N8j/lvUGy9NOLn01jUe0WymdqqdrYZ0J0LVQaOSnwf8IVriZx48RiHB8r4xgiPkUGo9 BoqA== authentication-results: spf=pass (sender IP is 209.85.210.169) smtp.mailfrom=laptop.org; mit.edu; dkim=pass (signature was verified) header.d=laptop-org.20150623.gappssmtp.com; mit.edu; dmarc=bestguesspass action=none header.from=laptop.org;compauth=pass reason=109 user-agent: Mutt/1.9.4 (2018-02-28) errors-to: piclist-bounces@mit.edu list-id: "Microcontroller discussion list - Public." list-post: x-beenthere: piclist@mit.edu x-mailman-version: 2.1.6 x-received: by 2002:a63:1515:: with SMTP id v21mr600902pgl.229.1588913806272; Thu, 07 May 2020 21:56:46 -0700 (PDT) x-topics: [EE] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 On Sat, May 02, 2020 at 10:19:48AM +1000, James Cameron wrote: > - three power boards, switched six-outlet, with built in red LED > power indicator; the LEDs no longer glow on two of the boards, but > the area around them is heated on all three boards, New one from stock got warm and stank. A red LED 5mm round package and a 68k 5% 2W resistor mounted on a small PCB. http://dev.laptop.org/~quozl/tmp/.20200508-pcb.png 250V AC 50 Hz active -> LED -> resistor -> neutral. Thermal camera showed the resistor was hot, and nothing else. Couldn't be bothered returning it, so I cut the resistor out and marked the front face with a cross over the LED. Resistor was tested as 67.7k Guess the stink was from resistor, PCB, or a conformal coating. --=20 James Cameron http://quozl.netrek.org/ --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .