GeorgeP Posted May 29, 2013 Report Share Posted May 29, 2013 I have returned things to Mouser with no issue and full refund, even where I changed my mind. The real question is who will cover the return shipping on those bad boys - they look almost beer can sized. Quote Link to comment Share on other sites More sharing options...
justin Posted May 29, 2013 Report Share Posted May 29, 2013 use for singlepower repairs? Quote Link to comment Share on other sites More sharing options...
GeorgeP Posted May 29, 2013 Report Share Posted May 29, 2013 use for singlepower repairs? If Mikhail did the repair wouldn't that mean he would just glue them to the top cover and not actually attach them to the circuit? Quote Link to comment Share on other sites More sharing options...
shipsupt Posted May 29, 2013 Report Share Posted May 29, 2013 I'm a little surprised at spritzer didn't say as long as we've got them lets build a monster around them. Thanks for catching the Mouser error. I'll be sending them back this week. Hopefully that will get them to cover shipping because beer can size is about right and they are full and heavy! Quote Link to comment Share on other sites More sharing options...
spritzer Posted May 29, 2013 Report Share Posted May 29, 2013 Hey!!! I just got home from work... 400V isn't enough for any serious amp. I have some 3900uf/550V caps here somewhere and some 3*110uf/630V film caps. Two of them are the size of that 717... Quote Link to comment Share on other sites More sharing options...
s_r Posted June 4, 2013 Report Share Posted June 4, 2013 How much output current could one really get away with for the offboard version? I actually had my working board running at ~10mA by swapping R5 and R6 with 100ohm resistors. After nearly an hour being on the outside of the heatsink reached about 37C, also the lowest I could get the offset was 7V. Quote Link to comment Share on other sites More sharing options...
johnwmclean Posted June 4, 2013 Report Share Posted June 4, 2013 8.8mA here. I can get within 5V. Drift will rise the more you increase current. Quote Link to comment Share on other sites More sharing options...
spritzer Posted June 4, 2013 Report Share Posted June 4, 2013 Which version are you using, IXYS or the A1968? Personally I'd only do this on the Sanyo part... As for how much current, until there is smoke. You can also tweak the offset series resistor to give you more range. Quote Link to comment Share on other sites More sharing options...
s_r Posted June 4, 2013 Report Share Posted June 4, 2013 I'm using the 1968s. So would I lower the value of the 2k resistor then (R26)? I'll probably just leave it at 10mA though, not going to be running anything but a lambda with it for a while. Quote Link to comment Share on other sites More sharing options...
Victor Chew Posted June 4, 2013 Report Share Posted June 4, 2013 (edited) I'm using the 1968s. So would I lower the value of the 2k resistor then (R26)? I'll probably just leave it at 10mA though, not going to be running anything but a lambda with it for a while.I was running at 34v (using ixys parts) when I ran out of turns. Lowered R26 to 1.2k and the problem was fixed. I believe that current variation is the same as the ixys parts, you may want to try dropping it to 1.5k. For some strange reason, both my on-board and off-board suffered the same problem. Edited June 4, 2013 by Victor Chew Quote Link to comment Share on other sites More sharing options...
GeorgeP Posted June 4, 2013 Report Share Posted June 4, 2013 Could you not use a 2k pot instead of the 1k pot to also deal with the issue, or is that to be avoided? Quote Link to comment Share on other sites More sharing options...
spritzer Posted June 4, 2013 Report Share Posted June 4, 2013 There are voltage issues at play here so stick with the 1K pot. Quote Link to comment Share on other sites More sharing options...
johnwmclean Posted June 4, 2013 Report Share Posted June 4, 2013 8.8mA here. I can get within 5V. Drift will rise the more you increase current. Sorry s_r, I was not clear. I’m able to zero offset, but it drifts 5V - 0 + 5V because of the extra current. As the guys have said R26 needs to be a lower value if your pegged at 7V. Quote Link to comment Share on other sites More sharing options...
Emooze Posted June 9, 2013 Report Share Posted June 9, 2013 So put in a new set of zeners, ohmed out the traces to make sure I didn't wreck something and everything checked out. Turned it on and something made a small zap. I got 750V on the output and about 320 across the zeners. I'm starting to think I should just populate a new board. Quote Link to comment Share on other sites More sharing options...
shipsupt Posted June 9, 2013 Report Share Posted June 9, 2013 Maybe not a good night for KGSShv power boards! I powered up my board for the first time and had a nice little spark at R17. I was not able to keep it powered up to do any checks as it was giving me a nice steady snap, snap, snap. Nothing else visually appears damaged. After removing the resistor (which tested OK after removal) I noticed this hanging solder and wondered if I had a cold joint that allowed some arcing? Do I need to protect that board now where the arc has gouged into the copper? I tried putting another resistor in and had the same result, arcing in the same spot. I'm calling it a night, starting to get tired which is not a good time to start trouble shooting high voltage. Quote Link to comment Share on other sites More sharing options...
spritzer Posted June 9, 2013 Report Share Posted June 9, 2013 Carbon is an excellent conductor so clean all that off and seal the exposed copper somehow. Glue, varnish, something like that. Quote Link to comment Share on other sites More sharing options...
jwzhan Posted June 9, 2013 Report Share Posted June 9, 2013 It's a bad idea to solder the voltage reference in there as those are very easily damaged. If you read previous posts, you can see that I had a strange problem with mine. Do what Birgir said. clean those nasty stuff off and tape it up with a small piece of kapton or seal it with epoxy. Pull all active components out and test them individually. Also... I can see quite a few very very large balls of solder.... come on... clean those shit up.... even if they aren't arcing right now, they will in the future for sure. I would highly recommend after the soldering job, go back and add some quality flux to every joint and reheat them to make them all nice, smooth, and shinny. If you can make the solder just seep through a little to the other side of the board all the better, but not like those balls of solder tho. And good luck! Quote Link to comment Share on other sites More sharing options...
livewire Posted June 9, 2013 Report Share Posted June 9, 2013 @shipsupt - Quote Link to comment Share on other sites More sharing options...
GeorgeP Posted June 9, 2013 Report Share Posted June 9, 2013 Maybe not a good night for KGSShv power boards! I powered up my board for the first time and had a nice little spark at R17. I was not able to keep it powered up to do any checks as it was giving me a nice steady snap, snap, snap. Nothing else visually appears damaged. After removing the resistor (which tested OK after removal) I noticed this hanging solder and wondered if I had a cold joint that allowed some arcing? Do I need to protect that board now where the arc has gouged into the copper? I tried putting another resistor in and had the same result, arcing in the same spot. I'm calling it a night, starting to get tired which is not a good time to start trouble shooting high voltage. What are you using to insulate your 7815 and 7915? Quote Link to comment Share on other sites More sharing options...
livewire Posted June 9, 2013 Report Share Posted June 9, 2013 O_o Quote Link to comment Share on other sites More sharing options...
jwzhan Posted June 9, 2013 Report Share Posted June 9, 2013 (edited) Well alomost all 78XX and 79XX today have tab connected to ground, so it's not a safety hazard per se. Grounding problem, however, is an entirely different matter. my bad, 78XX has tab connected to ground while 79XX has it connected to input. Edited June 10, 2013 by jwzhan Quote Link to comment Share on other sites More sharing options...
kevin gilmore Posted June 10, 2013 Author Report Share Posted June 10, 2013 NO, you have to use a thermal insulator on the 78xx and 79xx tabs are not ground Quote Link to comment Share on other sites More sharing options...
eggil Posted June 10, 2013 Report Share Posted June 10, 2013 non insulated parts need insulation (i.e. 4171G ceramic pads) plus thermal paste. Quote Link to comment Share on other sites More sharing options...
justin Posted June 10, 2013 Report Share Posted June 10, 2013 and are those flat head screws? Quote Link to comment Share on other sites More sharing options...
eggil Posted June 10, 2013 Report Share Posted June 10, 2013 (edited) Yeah, panhead would be better. That snapping cracking sound must have been disturbing... That 50k is in the negative rail though. I am not sure I follow how only that resistor blew, just by its little self. Edited June 10, 2013 by eggil Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.