rambinator Posted October 9, 2005 Report Share Posted October 9, 2005 Hi!It's quite late here (in the middle of the night :)) and I have been working on my motorfader-module. When I measure the Voltage at C4 it's 6,45V only which is way to low. The faders just move a little.Now a small story which might have nothing to do with that, so you don't have to read it:I couldn't find out what could be the cause, so I thought I might have connected the 1k pot in a wrong way. I'm not an electronic engineer and I had some beer so there might be some stupid thoughts behind that...I have the pcb from mike and it has 4 pads and 4 drilled holes where there should be 3 for the pot. (there are just 3 green pads in the brd-file). Well I then tried the "other" possible way the pot could be connected, resulting in a mf-voltage of 10V and a small fire between the pot and C3 which melted the cap's isolation... I think I can fix that tommorow... still have a pot and a cap somewhere.. hope that nothing else has been fried.Just to be sure that this was a stupid idea...... the 4th hole is where I drawed the red dot. that's where I moved the bottom pin of the pot when the inferno broke loose... Well I really don't know why mike drilled this hole (anyway the all of the holes where too small for the pot he sent me with it).But now back to the MF-Voltage and the question why it is that low. I tried with different psu's from 12-15V with the same result. Any ideas?Is it normal that the LM317 get REALLY hot? I put a small heatsink on it when I realized that but I still don't trust it. Could that have to do with my voltage problem.I hope someone with a little more knowledge can help. cheers,rambinator Quote Link to comment Share on other sites More sharing options...
rambinator Posted October 9, 2005 Author Report Share Posted October 9, 2005 Damn what a nightmare! I just didn' realize that the lm317 pins in reality are from left to right "adjust, output, input" and not "input, adjust, output"...But back to the voltage problem... from the datasheet of the voltage-regulator I see that the higher the pots resistance the higher the output voltage. If I turn the 1K pot up completly theres just 6,45V just as I sais. Maybe 1K is not enough. The example circuit in the datasheet has a 5K pot. Quote Link to comment Share on other sites More sharing options...
rambinator Posted October 9, 2005 Author Report Share Posted October 9, 2005 Well, I now put a 10K pot in and it's now possible to get 8V. One should really read the schematics before soldering something to "get it work now". The faders are really moving now!!! although not smoothly yet, will have to work on that. With a 10k pot it's quite difficult to fine-adjust the voltage. This mornig I thought about this "extra-hole" thing again and I came up with the idea that there might be pots with an anclosure which has some sort of pin in the middle for fixation... ???the regulator still gets very hot! do I need active cooling? Quote Link to comment Share on other sites More sharing options...
rambinator Posted October 12, 2005 Author Report Share Posted October 12, 2005 problem with the heat is solved. the motordrives were consuming way too much current because they were sort of blocked due to fals connection. now it works pretty well without getting hot. how do I declare a thread "solved" in this subforum? Quote Link to comment Share on other sites More sharing options...
smashtv Posted October 13, 2005 Report Share Posted October 13, 2005 how do I declare a thread "solved" in this subforum?I added (solved) to the subject of the first post in the thread.....I -think- the original poster can edit the subject too (never tried).....Best!Smash Quote Link to comment Share on other sites More sharing options...
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