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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / February 2005stereo loses settings when startup
Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set stations, it remembers fine going from on to off to access to off. But! When I start i, the starter seems to drop the "voltage threshold"(at least that's what I visualize) such that all memory settings are lost. Ideas, please? Thank you, s > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > stations, it remembers fine going from on to off to access to off. But! > When I start i, the starter seems to drop the "voltage threshold"(at least > that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s Maybe a small 12V battery or large capacitor that's hooked up with a diode between it and the car battery so voltage to the stereo won't drop when the car battery voltage drops significantly. -Bruce > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > > stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 7 lines] > > -Bruce Bruce, thanks. I like these ideas, and prefer the capacitor idea. But, I need specifics; I understand the theory & agree with you on both. But my background is ME instead of EE, so I need someone to do a 'practical design' so I can assemble the components. More help, please? Sorry to ask so much, but I'll admit where my knowledge ends! s >> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >> > stations, it remembers fine going from on to off to access to off. [quoted text clipped - 20 lines] > so I can assemble the components. More help, please? Sorry to ask so > much, but I'll admit where my knowledge ends! s I would imagine you could use an IN4001 diode and wire that from a constant 12V to the positive terminal of the capacitor which is connected to the constant power lead of your radio. The negative terminal of the capacitor should be connected to the ground of the radio. Everything else should remain the same. How big a capacitor? That's a good question. Let me think outquiet. Energy stored in a Capacitor = 1/2 C V*2 Joules 1 Joule is 1 watt for 1 second. Your radio will draw 50mA at 12.6 while the engine is off. That's equal to .63W and multiply for 5 seconds of cranking (I know, I'm doing a lot of assuming that things remain constant. Based on those figures, you'd need a 39000uF capacitor or bigger. (if I did my calculations right). It's been a long time since college. -Bruce >>> > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I >>> > set [quoted text clipped - 42 lines] > > -Bruce I'd be cautious of using a 1N4001 diode for this purpose as it has a current capacity of 1 amp. Unlike some older units, most newer head units draw full power from the "constant" lead and use the "switched" lead only as a signal for the head unit to power on/off - backwards of what one might tend to think. Other head units used the [typically orange] "constant" wire only for memory retention. The reason they have started using the "contant" wire instead of the "switched" wire for power is so that head units with logic-controlled cassette mechanisms, CD players, and motorized faceplates can load/eject with the ignition off. Roger >> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >> stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 5 lines] >between it and the car battery so voltage to the stereo won't drop when the >car battery voltage drops significantly. You need two diodes. One diode prevents the car from trying to charge the small batteries, and the second to keep the small batteries from trying to help crank the starter. The large capacitor will cause a voltage spike, just after the motor starts, so a choke coil will be needed to protect the sound unit. Here, in the Great White North (How's it goin', eh?), we would advise you that your battery is seriously short of cold cranking amperage and that you should buy the biggest battery that will fit in the tray. However, being designed for old-tech batteries, you should accept anything that covers half of your '55 studebaker's battery tray. While cold weather starting may be the least of your worries, a larger battery is the simplest (if not the cheapest) solution to your problem. > Here, in the Great White North (How's it goin', eh?), we would advise you > that [quoted text clipped - 5 lines] > the least of your worries, a larger battery is the simplest (if not the > cheapest) solution to your problem. I couldn't agree more, all those other fixes are just going to hide the symptom and not repair the problem which is either a bad battery, a bad connection or bad wiring. Bob > >> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > >> stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 19 lines] > the least of your worries, a larger battery is the simplest (if not the > cheapest) solution to your problem. Replacing the battery tray with one from a 56-64 Stude (assuming it's a C-K body, I'm not sure about sedans) will allow a larger battery to fit. nate > >> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > >> stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 5 lines] > >between it and the car battery so voltage to the stereo won't drop when the > >car battery voltage drops significantly. The large capacitor will cause a voltage > spike, just after the motor starts, so a choke coil will be needed to > protect the sound unit. Inductors generate spikes, not capacitors. The best arrangement has a choke in the supply line, with a capacitor between the hot side of the choke and ground. That'll swallow most interference. It would take a pretty big capacitor to keep a stereo happy. Spikes are generated by the starter solenoid and by the starter itself when the current is cut off. A capacitor cannot provide any higher voltage than it was provided with in the first place, but an inductor like a solenoid can make a 600-volt spike. I've measured it. It's the principle behind the ignition coil. > Here, in the Great White North (How's it goin', eh?), we would advise you that > your battery is seriously short of cold cranking amperage and that you [quoted text clipped - 3 lines] > the least of your worries, a larger battery is the simplest (if not the > cheapest) solution to your problem. A 35-watt electric battery blanket will make that battery perform. Some guys use them instead of a block heater. A battery loses something like 60% of its capacity at -25 degrees C. Dan >The large capacitor will cause a voltage >> spike, just after the motor starts, so a choke coil will be needed to [quoted text clipped - 5 lines] >interference. It would take a pretty big capacitor to keep a stereo >happy. The car sits with the engine not running for a long time, so the voltage on the capacitor drops to the battery terminal voltage (hopefully 12.6v). During cranking, the battery voltage drops to below the keep-alive threshold (whatever that is), but the low load of the audio system keep the cap at about 12.6v. The engine catches, and the alternator now cranks out current at a voltage that will charge the battery (14+ volts). The cap draws a current appropriate to two or more volts divided by the wire's resistance in ohms, or a few tens of amps. As all wires in the real world, running close (or within) large steel objects have non-zero inductance, the circuit will ring. Without the capacitor, the switching transient is not as bad, as there is no apparent short circuit to a lower voltage, so there is no inrush overcurrent. Switching transients always happen. Capacitors make them worse. On some powerlines, switched capacitor banks are more serious than lightning strikes. Although it is possible, most aftermarket stereos are quite that sensitive. My first bet would be on a bad or marginal ground connection for the radio. Run a separate ground to the battery and a fused positive lead to the battery and if that eliminates the problem. I have had a variety or 1950-1967 vehicles and failed ground connections from alternator/generator to block to chassis to dash can be problematic. Good luck. Don > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > stations, it remembers fine going from on to off to access to off. But! > When I start i, the starter seems to drop the "voltage threshold"(at least > that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >stations, it remembers fine going from on to off to access to off. But! >When I start i, the starter seems to drop the "voltage threshold"(at least >that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s Have you checked the retained power line to make sure that it still has power when the starter is engaged? If it doesn't have power even for a couple seconds your radio will loose its settings. Steve B. > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > >stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 7 lines] > > Steve B. This is what I was thinking. Maintaining memory settings were no that big an issue back in '55, so a hard line to the battery might be hard to come by. Its best to run a dedicated wire from the battery (+), with an in-line fuse near the battery to the radio 'battery' input. If the radio is supposedly already connected to a hot point, the radio dropping out might be a symptom of a dirty, weak or loose connection, or a charging system problem.  SignaturePaul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ RAM disk is *not* an installation procedure. >>> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >>>stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 11 lines] > big an issue back in '55, so a hard line to the battery might be hard to > come by. Not at all, just pick it off the back of the ammeter or the "battery" post on the ignition switch. Both are ring terminals with nuts. > Its best to run a dedicated wire from the battery (+), with an in-line > fuse near the battery to the radio 'battery' input. If the radio is > supposedly already connected to a hot point, the radio dropping out > might be a symptom of a dirty, weak or loose connection, or a charging > system problem. > yes, an inline fuse is a must, as the wire to the ammeter is *not* fused. Also would be an excellent idea to put some fusible links or high-amp fuses inline up at the starter solenoid. Nothing sucks worse than a Stude with a crispy wiring harness... um, or so I've heard. (did I post about the last car show I went to...?) nate PS - sdlomi, if you haven't already, come on over to alt.autos.studebaker for the more Stude-specific questions you will undoubtedly have. Also check out my cheezy, suck-a.s web site (see .sig) to get you started towards some better Stude-related sites (stude.com and the forums at SDC are good, also Bob J's page and... well there's lots of them, really.) Signaturereplace "fly" with "com" to reply. http://home.comcast.net/~njnagel >>> Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set >>>stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 8 lines] >> >> Steve B. You may have to connect the player to something that does not draw alot of power upon startup.... for instance the headlights, or brake lights... Good Luck.. Fwed > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > stations, it remembers fine going from on to off to access to off. But! > When I start i, the starter seems to drop the "voltage threshold"(at least > that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s I'm assuming that this must have been converted to 12V at some point in time? Sounds to me like you need to look at the battery, cables, wiring etc... nate That usually means a corroded or undersized connection on the ground to me. If the body doesn't have a good ground tag, then the starter can draw enough to drop the body power way down. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > stations, it remembers fine going from on to off to access to off. But! > When I start i, the starter seems to drop the "voltage threshold"(at least > that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > stations, it remembers fine going from on to off to access to off. But! > When I start i, the starter seems to drop the "voltage threshold"(at least > that's what I visualize) such that all memory settings are lost. > Ideas, please? Thank you, s IRRC the start position disconnects the acc post to prevent drawing current the wrong way. The memory should be connected to +12V line, not the ignition switch or circuit controlled by it. Chas Hurst > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > > stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 7 lines] > > Chas Hurst We tried fusing a + line straight to the battery post--other thoughts? Thanks, Charles. s > > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > > > stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 13 lines] > We tried fusing a + line straight to the battery post--other thoughts? > Thanks, Charles. s I would run a booster cable from the battery negative to the radio case or the radio ground wire to see if that fixes it. Mike 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's > > > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > > > > stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 20 lines] > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 > 88 Cherokee 235 BFG AT's Thx, Mike. We'll do just that this evening. Sounds like the "next" logical thing to try. s > > > Help! Got a '55 Studebaker. Aftermkt. mp3/cd/amfm radio. If I set > > > stations, it remembers fine going from on to off to access to off. But! [quoted text clipped - 13 lines] > We tried fusing a + line straight to the battery post--other thoughts? > Thanks, Charles. s Connect an ammeter in the +12V line and see which way the current flows when starting. Check again that the radio is wired properly. |
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