oberg Posted August 3, 2004 Report Share Posted August 3, 2004 Hi all!My name is Robin Öberg. I live in Falun / Sweden and I'm currently trying to turn some old C64:s into a masterpiece.  ;)I've just completed my first veroboard-circuit trying to get the optimized C64 PSU-thing working. Everything seems ok and the LED lights up just fine. The thing is though that I get 18,1 V DC instead of the 14 V I wanted. The LEDport reads 5,2 V DC as does the other port. I've checked everything and I think I've succeded in copying Torsten´s design to veroboard. Any ideas where I could have misplaced something would be of great value. Thanks!I've included some pictures, but since the construction is kind of messy I'm not sure if they are of any help.Left view, capacitators marked.Right view, capacitators marked.Top view, voltages marked.Edit: My recycled PSU gives me 5,2 V DC and 10,5 V AC (instead of 9) - could that explain it? Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 Hi all!My name is Robin Öberg. I live in Falun / Sweden and I'm currently trying to turn some old C64:s into a masterpiece.  ;)I've just completed my first veroboard-circuit trying to get the optimized C64 PSU-thing working. Everything seems ok and the LED lights up just fine. The thing is though that I get 18,1 V DC instead of the 14 V I wanted. The LEDport reads 5,2 V DC as does the other port. I've checked everything and I think I've succeded in copying Torsten´s design to veroboard. Any ideas where I could have misplaced something would be of great value. Thanks!I've included some pictures, but since the construction is kind of messy I'm not sure if they are of any help.Left view, capacitators marked.Right view, capacitators marked.Top view, voltages marked.Edit: My recycled PSU gives me 5,2 V DC and 10,5 V AC (instead of 9) - could that explain it? Quote Link to comment Share on other sites More sharing options...
doc Posted August 3, 2004 Report Share Posted August 3, 2004 Hard to answer with this pictures ...First of all: the 10,5 V AC ar ok !Your regulator is a 78L09 ? The 18,1 V: Did you measure the 18,1V under load ?If not: Try to measure under load. For example with a 10K resistor as load (connected between ground and the 14VDC pin). Another thing: What is the type of your bridge-rectifier ? greets Doc Quote Link to comment Share on other sites More sharing options...
doc Posted August 3, 2004 Report Share Posted August 3, 2004 Hard to answer with this pictures ...First of all: the 10,5 V AC ar ok !Your regulator is a 78L09 ? The 18,1 V: Did you measure the 18,1V under load ?If not: Try to measure under load. For example with a 10K resistor as load (connected between ground and the 14VDC pin). Another thing: What is the type of your bridge-rectifier ? greets Doc Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 Thanks Doc!The pictures are colorful and all - but not that helpful I guess. :-[I'm using a "78L09" regulator and the rectifier is a "B40C800DIP". The 18 volts are measured "as is/unloaded". I'll measure again using a resistor when I get home. Thanks! Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 Thanks Doc!The pictures are colorful and all - but not that helpful I guess. :-[I'm using a "78L09" regulator and the rectifier is a "B40C800DIP". The 18 volts are measured "as is/unloaded". I'll measure again using a resistor when I get home. Thanks! Quote Link to comment Share on other sites More sharing options...
titan Posted August 3, 2004 Report Share Posted August 3, 2004 With 5V and 10V its strictly impossible to have 18 V .Maybe the Ground of the voltage regulator isnt connect correctly or something like that? ??? :o Quote Link to comment Share on other sites More sharing options...
titan Posted August 3, 2004 Report Share Posted August 3, 2004 With 5V and 10V its strictly impossible to have 18 V .Maybe the Ground of the voltage regulator isnt connect correctly or something like that? ??? :o Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 That's an idea. I'll triplecheck all my solderings. Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 That's an idea. I'll triplecheck all my solderings. Quote Link to comment Share on other sites More sharing options...
pay_c Posted August 3, 2004 Report Share Posted August 3, 2004 Little thing: The SID needs 12 Volt @ very low current. So it should be no prob to get the 18 Volt down to 12 or 9 Volt without to much heat (heatsink really not needed!).So, if you can´t find any solution, just forget it right now and go on.And: 10 kOhm @ 18 Volt is not really a "Load": That´s just 1,8 mA...The voltage will go down with some more current (@ about 50 mA) for sure.Greetz! :) Quote Link to comment Share on other sites More sharing options...
pay_c Posted August 3, 2004 Report Share Posted August 3, 2004 Little thing: The SID needs 12 Volt @ very low current. So it should be no prob to get the 18 Volt down to 12 or 9 Volt without to much heat (heatsink really not needed!).So, if you can´t find any solution, just forget it right now and go on.And: 10 kOhm @ 18 Volt is not really a "Load": That´s just 1,8 mA...The voltage will go down with some more current (@ about 50 mA) for sure.Greetz! :) Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 I've gone through the veroboard again, and when measuring with a 10k load the voltages read 17,7.The ground pin of the 78L09 seems connected alright and measuring on the regulator pins gives me- leg 1 to leg 2 13,4 V - leg 3 to leg 2 12,8 VWhen measuring from + on the bridge-rectifier to ground I get the same 18 volts - but when measuring from + to - (both on the rectifier) I get 13,4 V. Does that seem ok?[pay_c]: Ok, so I'll just stick with my 18v and let the regulators on the SID-module do the work?Thanks for all your help! Quote Link to comment Share on other sites More sharing options...
oberg Posted August 3, 2004 Author Report Share Posted August 3, 2004 I've gone through the veroboard again, and when measuring with a 10k load the voltages read 17,7.The ground pin of the 78L09 seems connected alright and measuring on the regulator pins gives me- leg 1 to leg 2 13,4 V - leg 3 to leg 2 12,8 VWhen measuring from + on the bridge-rectifier to ground I get the same 18 volts - but when measuring from + to - (both on the rectifier) I get 13,4 V. Does that seem ok?[pay_c]: Ok, so I'll just stick with my 18v and let the regulators on the SID-module do the work?Thanks for all your help! Quote Link to comment Share on other sites More sharing options...
oberg Posted August 9, 2004 Author Report Share Posted August 9, 2004 It was the 78L09 placed backwards. I must have misunderstood the datasheet I looked at... :-[ Quote Link to comment Share on other sites More sharing options...
oberg Posted August 9, 2004 Author Report Share Posted August 9, 2004 It was the 78L09 placed backwards. I must have misunderstood the datasheet I looked at... :-[ 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.