---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 06/16/11: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:58 AM - Re: AEC 9009 Audio Amplifier Troubleshooting Questions (Jared Yates) 2. 08:14 AM - Re: Photo FET Optocoupler (John Grosse) 3. 08:22 AM - Re: AEC 9009 Audio Amplifier Troubleshooting Questions (Robert L. Nuckolls, III) 4. 08:23 AM - Re: Photo FET Optocoupler (Robert L. Nuckolls, III) 5. 09:39 AM - Re: Photo FET Optocoupler (John Grosse) 6. 09:46 AM - Re: Photo FET Optocoupler (Robert L. Nuckolls, III) 7. 11:34 AM - Re: Photo FET Optocoupler (Daniel Hooper) ________________________________ Message 1 _____________________________________ Time: 07:58:04 AM PST US Subject: Re: AeroElectric-List: AEC 9009 Audio Amplifier Troubleshooting Questions From: Jared Yates Indeed, I had installed the 122 backwards. It works now, thanks! On Jun 15, 2011, at 22:45, "Robert L. Nuckolls, III" wrote: > > At 07:39 PM 6/15/2011, you wrote: >> I just got to the point where I can test my home-made audio amplifier, but it isn't working yet, and I was hoping I might be able to get some help from those who have built the circuit before to help narrow down the troubleshooting. I wired it up, applied power, and it blew the 1A fuse. I looked everything over to be sure that I didn't have any obvious shorts and couldn't find any. Just to be sure that the rest of the wiring wasn't the problem, I removed all of the wires except for the power and ground, but it still blows the fuse. I went through each component and verified the placement of the ICs and resistors. I did notice that I had one capacitor backwards, number 127, 1uF capacitor. I reversed it but still didn't notice any difference. Is there an easy way to test a capacitor to see if it is still good? There isn't any physical damage to any of them. > > Hmmm . . . I wish I had called out sockets under the > amplifiers so that the builder can power it up with the > ic's out. > > Capacitor size is not terribly critical but polarity > is. MOST of the times you get a hot LM317 is for > a reversed capacitor C122. > > Do an ohmmeter test from pin 6 to ground on either > of the two amplifier chips. It should be non-zero. > Actual measurement depends on your ohmmeter and > polarity of the ohmmeter connections. The main > thing is that it should be some substantial number > showing that the path is not shorted. > > > >> I replaced the fuse with my multimeter leads to try and measure how much current it was taking, but the meter read zero, so I turned off the switch after a second or so. After that test the 317 was warm, but not hot, and nothing seemed to be smoking. > > When powered up, you should have just under 9v > on pin 6 of the two amplifiers. I don't know how > you heat up the LM317 with zero current. Check > the measurement setup. > > > Bob . . . > > > > ________________________________ Message 2 _____________________________________ Time: 08:14:38 AM PST US From: John Grosse Subject: Re: AeroElectric-List: Photo FET Optocoupler The voltage from the gauge is +5v or 0 with respect to ground. The bulb is incandescent: 140 mW at 5 VDC, but that was what I was going to use when I thought a direct connection to the gauge would work. Now I'll use a #73 which is 1.12W at 14 VDC . Yes I can turn the bulb on by pulling it to ground. John > ------------------------------------------------------------------------ > > Robert L. Nuckolls, III > June 15, 2011 9:57 PM > > > At 08:30 PM 6/15/2011, you wrote: > > Doesn't need to be a photo-fet. There are plenty of LED > couplers that would work. Is the 5v output measured with > respect to ground . . . and does it go to zero volts > in the off state? Can you turn the bulb on by pulling > its control lead to ground? 28 mA lamp sounds like an > LED, no? > > Emacs! > > > OOPS! You said pressure gage? Is this output a linear > voltage that represents pressure or some voltage that is > zero some times and 5v other times? > > Bob . . . > ________________________________ Message 3 _____________________________________ Time: 08:22:27 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: AEC 9009 Audio Amplifier Troubleshooting Questions At 10:53 AM 6/16/2011, you wrote: > >Indeed, I had installed the 122 backwards. It works now, thanks! You might want to consider replacing the capacitor. Reversed polarity can have deleterious effects on service life. Bob . . . ________________________________ Message 4 _____________________________________ Time: 08:23:14 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Photo FET Optocoupler At 11:11 AM 6/16/2011, you wrote: > >The voltage from the gauge is +5v or 0 with respect to ground. The >bulb is incandescent: 140 mW at 5 VDC, but that was what I was going >to use when I thought a direct connection to the gauge would work. >Now I'll use a #73 which is 1.12W at 14 VDC . Yes I can turn the >bulb on by pulling it to ground. The the single transistor buffer suggested by myself and others is a practical solution. Bob . . . ________________________________ Message 5 _____________________________________ Time: 09:39:14 AM PST US From: John Grosse Subject: Re: AeroElectric-List: Photo FET Optocoupler I'm curious why Daniel recommended a 2.2K resistor and you suggested a 1K resistor. Thanks to both for your suggestions. This looks like it should work for me well. John > ------------------------------------------------------------------------ > > Robert L. Nuckolls, III > June 16, 2011 10:20 AM > > > > > > The the single transistor buffer suggested by myself > and others is a practical solution. > > > Bob . . . > > ________________________________ Message 6 _____________________________________ Time: 09:46:45 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Photo FET Optocoupler At 12:34 PM 6/16/2011, you wrote: > >I'm curious why Daniel recommended a 2.2K resistor and you suggested >a 1K resistor. Not critical. Throw a dart and anything from 1k to 50K would probably work. Bob . . . ________________________________ Message 7 _____________________________________ Time: 11:34:57 AM PST US Subject: Re: AeroElectric-List: Photo FET Optocoupler From: Daniel Hooper I actually thought about it, changed to a 1K, then changed back to a 2.2K before I sent it. I guess I just like the color red.. haha On Thu, Jun 16, 2011 at 11:43 AM, Robert L. Nuckolls, III wrote: > > > At 12:34 PM 6/16/2011, you wrote: >> >> >> >> I'm curious why Daniel recommended a 2.2K resistor and you suggested a 1K >> resistor. > > Not critical. Throw a dart and anything from 1k to 50K would probably > work. > > > Bob . . . > > -- Daniel Hooper ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.