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This text is posted for me to http://www.electronics-lab.com/forum/index.php?board=13;action=display;threadid=196;start=165 ***************************************************** I don't understand like they where carried out the calculations of this original PSU from Mixos. I have carried out the following changes: D1 D2 D3 D4 for component brige S4VB (8A 200V) with heatsink C1 3300uF x 50V for 10000uF x 50V R7 0.47 ohms 5W for 0.47 ohms 10W Q2 2N2219 for TIP31A with heatsink R15 1K 1/4W for 100 ohms 1/2W Q4 2N3055 with heatsink and fan The correccion suggest AUDIOGURU, thank's!!! Working with 1V 3A the brige burn not hot R7 burn 2N3055 very hot He wanted to know that you probe I carry out. Since the values of the original components are very below those that I have changed. I was very silly of not seeing that the difference of Voltage, 24 V to 1v it represent 23V * 3A = 69W this is the heat to dissipate for 2N3055 is to much for one device, the heatsink is to big. The power dissipation at 25 grade centigrade is 115W but TC case 75 grade is only ~60 grade. I request them they excuse me but it was very delighted with this PSU thinking that it had already bean proven (testeada). In any way the idea is very good but there would be that dimension most of the components ones and therefore the printed circuit. Until soon and thank you. ************************************************* I am very happy of being able to speak with you. C1 across Voltage is 31V I am a doctor in medicine but I like the electronics for that reason I am studying ,my I finish exam it was regrettably on feeding sources (PSU) when I began this project it doesn't revise my notes. For example for an output of 30V 3A the VA to transformer it should be 207W. The value for rectifiers it is of three times the half current n this case 9A and the voltage for each diode 200V. The C1 = (40 * 10000) / RLoad For 30V 3A RLoad = 10 ohms C1 = 40000uF insulation is output to filter more 50% in this case around 150V.(it is loaded to the pick tension 60V minimum). I can be mistaken but it is what you/they taught me . I thank you your attention By AudioGuru

Hi my friend: I make the changes Full-Bridge rectifier 8A 200V C1 10000uF 50V Q2 TIP31C with heatsink R15 100 ohms R7 10W The measurment are: Not RLoad (not charge) 27V RLoad 100 ohms 10W 25V 0.25A RLoad 50 ohms 10W 23.8V Rload 25 ohms 10W 23.4V 0.55A RLoad 10 ohms 10W 19,8V 1.7A One Car Bulb (Lamp) 12V 20W 12V 1.66A Two Car Bulb in // parallel 12V 3.47A Two Car Bulb in series (10V across each lamp) 20V 1.55A What is your appreciation??? Sorry my english is horrible Thank's AudioGuru

Hi Audioguru Ok this change I'cant make. R7 is 5W suggest more?? Q1 is BC548 You suggest change?? What dimension heatsink for Q2?? Thank's

Thanks, Thanks, Thanks.... R7 is open the PSU start I was very upset because my PSU didn't work What change do You suggest to make in the PSU??. The device TLE2141CP and MC34071AP is not able in my country but TIP31A and the other component is available Best regards AUDIOGURU

Hi!! Sorry for my english is only technic My PSU is original circuit. The PSU not start Led is ligh permanetly Volt across C1 (33.2V) Volt pin 6 (U3) and point 4(ground) (-5.8V) Volt pin 6 (U1) and point 4(ground) (11.5V) Volt pin 6 (U2) and point 4(ground) (-5.3V) Volt across R15 (3.9V) Volt across Base-emitter Q4 (0V) Volt across Base-emitter Q2 (0.7V) Thank in advance