Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 AFAIR, there is a diode after each 9v battery, and two sets of caps between V+ and ground and V- and ground each. There is a series resistor inside each 9V rechargeable lithium battery, as I recall, but I can't figure out why they won't work with the SR-71. Any ideas why? Quote Link to comment Share on other sites More sharing options...
aardvark baguette Posted October 2, 2008 Report Share Posted October 2, 2008 because I require food energy to function. not batteries. Failing that, Mountain Dew. Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 because I require food energy to function. not batteries. Failing that, Mountain Dew. you duplicate sound in real time? Quote Link to comment Share on other sites More sharing options...
aardvark baguette Posted October 2, 2008 Report Share Posted October 2, 2008 **clears throat** "ahhhhhhhhh". Quote Link to comment Share on other sites More sharing options...
hYdrociTy Posted October 2, 2008 Report Share Posted October 2, 2008 because it's no longer pretend dual mono Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 Another piece of humor that escapes me? Guess I'm not yet in synch with this forum, but I am trying. Seriously, anyone know? Quote Link to comment Share on other sites More sharing options...
deepak Posted October 2, 2008 Report Share Posted October 2, 2008 Another piece of humor that escapes me? Guess I'm not yet in synch with this forum, but I am trying. That's pretty obvious. Quote Link to comment Share on other sites More sharing options...
justin Posted October 2, 2008 Report Share Posted October 2, 2008 AFAIR, there is a diode after each 9v battery, and two sets of caps between V+ and ground and V- and ground each. There is a series resistor inside each 9V rechargeable lithium battery, as I recall, but I can't figure out why they won't work with the SR-71. Any ideas why? What happens if you put in an alkaline 9V and a li-ion 9V? Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 I haven't tried, and I don't have any alkalines lying around. Before I spend any money.. there is a point to what you're saying, I would presume. Do you suspect it is the cutoff inside the lithiums that might be faulty? Quote Link to comment Share on other sites More sharing options...
n_maher Posted October 2, 2008 Report Share Posted October 2, 2008 Yes, now it's the confusing moniker of 'dual headphone amplifier', whatever the heck that means. Quote Link to comment Share on other sites More sharing options...
justin Posted October 2, 2008 Report Share Posted October 2, 2008 There is no point, but if it doesnt work w/ 2x li-ion (what exactly do you mean by it doesn't work), then try 1x li-ion and 1x alkaline, and then see if it makes any difference if the li-ion is on the + or - side inside each cell is probably a protection circuit that looks something like this, so that needs to be added to the schematic Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 Thanks, I'll try it with one NiMH and one Li-Ion. With 2 Li-Ions it works for ~.5sec when I connect the second battery and when I disconnect it, but not when they're in. The circuit has, as far as I can tell, one diode each at the +V and -V of the batteries, dropping to two parallel caps and the opamps and buffers with filter caps, pretty standard except for the diodes. I bypassed the diodes but it still did not work (duh!). Don't have a schematic I can post, and am unsure of the circuit, anyway. Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 Just out of curiosity, the thermometers cost ~$2 ea. You sure there is one in each battery? Quote Link to comment Share on other sites More sharing options...
justin Posted October 2, 2008 Report Share Posted October 2, 2008 i dont know if they would have built in temperature protection, but they would at least have voltage and current protection. maybe the capacitors are enough to trigger the discharge current protection. try putting a resistor 10-100 ohms in series with each cell and see if it works Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 2, 2008 Report Share Posted October 2, 2008 I'll give that a try and post my results. Quote Link to comment Share on other sites More sharing options...
jinp6301 Posted October 2, 2008 Report Share Posted October 2, 2008 does anyone else think its funny that justin is answering questions about the SR-71? Quote Link to comment Share on other sites More sharing options...
Guest sacd lover Posted October 3, 2008 Report Share Posted October 3, 2008 does anyone else think its funny that justin is answering questions about the SR-71? He probably knows more about the design than Ray does. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted October 3, 2008 Report Share Posted October 3, 2008 does anyone else think its funny that justin is answering questions about the SR-71? Because i'm to busy... My guess is that the current draw is actually too low to keep the battery protection circuit turned on. Some of the Li-ion batteries do that. They are designed for a minimum of 10% power draw. And justin clearly knows more about that circuit than resistor ray. Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 3, 2008 Report Share Posted October 3, 2008 The debate just ended so I can post. It's weird. When I hook up two NiMHs with alligator clips, then, as the amp is running, switch one to iPowerUS Li-Polymer, then the other, it keeps running. But when I power up with a Li-Poly battery on one side, either side, and a NiMH on the other, or with both sides with Li-Polys, it powers up for ~.5sec and then shuts down. Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted October 3, 2008 Report Share Posted October 3, 2008 If this is true, then it is likely that the batteries charging the capacitors is causing an overcurrent condition and the batteries are turning off. Look up what the maximum output current for the battery is, replace the diodes with resistors to limit the maximum current. Should work fine. And drop less than the .7 volts that the diodes require. Don't ever get the batteries in backwards. Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 3, 2008 Report Share Posted October 3, 2008 Don't ever get the batteries in backwards. Only if I want the real Blackbird, with flames coming off its butt, and all... Quote Link to comment Share on other sites More sharing options...
Grahame Posted October 3, 2008 Report Share Posted October 3, 2008 Only if I want the real Blackbird, with flames coming off its butt, and all... Quote Link to comment Share on other sites More sharing options...
Guest receph Posted October 4, 2008 Report Share Posted October 4, 2008 Yes, of course, a 25ohm resistor at v- and v+ solved the problem. What else? (my 20/20 hindsight is working perfectly) Thank you guys I guess I was hoping that those thingies that look and act like diodes were "secret" components RS built and custom painted, this time with a devious substance that does not resemble nail polish. What a disappointment... Quote Link to comment Share on other sites More sharing options...
spritzer Posted October 4, 2008 Report Share Posted October 4, 2008 What a disappointment... This should be the RSA motto... Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted October 4, 2008 Report Share Posted October 4, 2008 Yes, of course, a 25ohm resistor at v- and v+ solved the problem. What else? (my 20/20 hindsight is working perfectly) I smell a high priced military spec modification service being offered by APL. Say $1500 to modify your sr-71a. Actually a pair of the appropriately rated CRD's or fets wired for same would be better than either diodes, or resistors. Quote Link to comment Share on other sites More sharing options...
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