docbrown Posted July 6, 2006 Report Share Posted July 6, 2006 it's not as if i didn't want all that equipment... there are many things i want... an oscilloscope (+ signal generator), a nice lab psu, a GOOD multimeter, a CNC machine, heaps of components for experiments... and i could go on and on...Understood... I'm just suggesting a way to troubleshoot... I hope you understand... :P Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 6, 2006 Author Report Share Posted July 6, 2006 yeah, i understand. i'll have to check how much that stuff costs. ok lets recapitulate what i need:BreadboardParts to emulate the PSU Input:uC 7805 0.17€D40C800 0.17€2200 uF electrolytic330 nF cap10 uF electrolytic100 nF capdid i miss anything? Quote Link to comment Share on other sites More sharing options...
Shum Posted July 7, 2006 Report Share Posted July 7, 2006 Hi,I see you that you still have not found what was wrong with the board's power supply. Just a suggestion, you have already removed the rectifier from the board and mounted a new one. What you can do to check the rectifier that you removed and connect wires as shown in the attached picture. Connect 9VDC from your PSU to the ~ side of the rectifier and measure the + and - side. You should get 9VDC as well. If this is the case the rectifier is ok. The there might be some other problem with the board. Check this out first and let see the result. Good luckShum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 7, 2006 Author Report Share Posted July 7, 2006 i already checked the first rectifier after removing it. it's completely dead, but that might also be due to my methods of removing it from the pcb... ::)the board *should* be ok, i ordered one of those pre-made ones from mike's electronics (or what it's called) and looked pretty much like the sample pcb i printed for mounting, except for an excess hole (far from the psu part, and absolutely harmless) Quote Link to comment Share on other sites More sharing options...
Shum Posted July 8, 2006 Report Share Posted July 8, 2006 Hi,Really cannot understand why this simple problem cannot be traced. We almost exhausted the steps that could be taken to solve this problem. Unfortunately you don't have a desoldering pump to help removing the components, other wise you could trace the fault by elimination. Is the layout of the pcb you bought similar to that found on Thorsten's site? What I would do in a difficult case is to cut the suspected pcb track so that I can isolate the circuit for testing, and solder it back afterwords. Would you be will to do this, if so I can use Thorsten's pcb layout and mark the place where you can cut the track for testing.Shum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 8, 2006 Author Report Share Posted July 8, 2006 it's the same as the core v2 module on the ucapps site Quote Link to comment Share on other sites More sharing options...
Shum Posted July 8, 2006 Report Share Posted July 8, 2006 Hi,Basically the v2 and v3 boards are the same. Anyway, can't think of anyother ways to help except what I mentioned earlier that you cut the track to check and bridge it back by soldering a piece of wire across the cut track. I am attaching here a photo of the board which I marked the cut. Please follow the instruction written on the photo. Since you have experience with amplifier and other audio stuff, it should be easy for you to do this. Good luck. Let me know how you are progressing.Shum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 8, 2006 Author Report Share Posted July 8, 2006 so basically i should take the capacitors out of the equation so that i can see if i get 9v when they are removed, but why should i get an ohmic resistance as soon as c5 (and c6) is charged? shouldn't i get an infinite resitance as there are no resistors there? Quote Link to comment Share on other sites More sharing options...
Shum Posted July 8, 2006 Report Share Posted July 8, 2006 Hi,Yes, once the the caps are charged you should get infinite resistance. Since you have other components such resistors and IC on the boad you would have some resistance reading (depending on polarity). There is a typo error on the last sentence at the bottom of the photo. It should read "will increase to some ohmic value later" (depending on polarity).Shum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 8, 2006 Author Report Share Posted July 8, 2006 actually no, it should turn infinite here as well. remember, the 7805 is removed (and i didn't put in a wire bridge, so everything else is connected only via ground, and not via "+5v" and should have no effect, and if i cut at the point you marked i would only be measuring the resistance between C5 and C6 Quote Link to comment Share on other sites More sharing options...
Shum Posted July 8, 2006 Report Share Posted July 8, 2006 Hi,I did,nt know that you have already removed the 7805. What about the optocoupler? is it still in the circuit. If you have not cut the track, what would be the reading (resistance), (1) at the + and - points of the C5, (2) between + and - points of C4 (or at J2). The readings need not be exact. If it should turn infinite as you mentioned, then there is no short between 5v and ground. If you had the rectifier in place, and you feed J1 with your PSU (9vdc), then you should get 9vdc between + and - pionts at C5. Can you do this part and le me know the result.As I mentioned, cutting the track and feeding J1 with 9vdc you will get 9vdc between + and - points at the rectifier. Measuring the resistance between + and ground of C5 and C6 is to establish if the was any short before applying power to J1. Shum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 8, 2006 Author Report Share Posted July 8, 2006 i never put the optocoupler in as according to the tips for soldering the core module. yeah, 9vdc is what i would have expected at the outputs of the rectifier even without that cut track, but that's not what i get... well, i'll try the cutting later on, maybe tomorrow. Quote Link to comment Share on other sites More sharing options...
Shum Posted July 9, 2006 Report Share Posted July 9, 2006 Hi,Let us summarise what had been done so far;(1) No ICs are being mounted on the board except the rectifier.(2) No short circuit between positive rail and ground (measured betweeb + and - points of C5.(3) Rectifier is mounted correctly with the two points marked ~ connected to J1.(4) Applied 9vdc from your psu to J1 and had only 0.9vdc across + and - of C5.Can you confirm what I listed above is correct.Please do two more measurements before you cut the track, (a) Use ohm-meter with its positive lead (red) at + point and negative lead (black) at - point of C5. What is the measured reading.(b) Do same measurement, this time with negative lead (black) at the + point and positive lead (red) at - point of C5. What is the reading.© Do ohmic measurement of J1 with positive lead of meter to one point and negative lead to the other and vice versa. What are the readings.Sorry for asking so many questions, I am trying to help.Shum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 9, 2006 Author Report Share Posted July 9, 2006 a: value started at -15k (precision setting: 200k) which would be the capacitor discharging, value kept rising and rising and after approx 5 minutes the value surpassed 200k so i got a display of infinity and switched to 2M precision where the displayed resitance jumped to 1.98M and kept rising. so yeah, i was charging the cap reaaaaal slowly...b: basically a in reverse, and honestly i didnt feel like holding the multimeter there for more than 5 minutes again...c: infinity (or more than 2 megaohms) regardless of polarity, this does seem strange and can't really be true. Quote Link to comment Share on other sites More sharing options...
Shum Posted July 9, 2006 Report Share Posted July 9, 2006 Hi,The reading on (a) is correct, but you need not hold the probes there for more than 5 minutes (few seconds would do). This test was to establish if there were a short. It has not. (b) is to check if the rectifier is ok. In this test you should get some resistance value(not infinity) reading. © shows that J1 terminals are connected to the ~ side of the rectifier, which is correct. All these tests indicated that you do not have a problem with the power circuit of the board. If you apply 9vdc to J1, you should get 9vdc at the + and - terminals of C5 as you have expected it also. I am really puzzled if you are not getting the 9vdc there. Sorry for not being able to help solve your problem if this is the case. ShumShum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 9, 2006 Author Report Share Posted July 9, 2006 well i reconnected the psu, got 0.09V this time at C5 and then figured that if everything seems ok, why is it wrong? i then checked the + an - pins of the rectifier directly by pushing the probes onto the pin ends directly (which wasn't particularly easy when the "helping hand" always slides away" and guess what? 9v. so yeah probably i fried the first rectifier and this one has a bad solder point (although it looks ok...) Quote Link to comment Share on other sites More sharing options...
Shum Posted July 9, 2006 Report Share Posted July 9, 2006 Well, good for you. So, you can now proceed to remount the 7805 and when it's done and powered up, you should get 5vdc between pins 3 and 2 of the 7805 or at J2. Good luck with the rest of your project.Shum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 10, 2006 Author Report Share Posted July 10, 2006 put in a new 7805 and now i got a nice and steady 5.04V at all pins mentioned in the soldering guide 8) i suppose i can put in the optocoupler and microcontroller now and connect the midi ports to check if my core is ok and then i can upload mios, right? (and then i'll start building the sid module and think about how i'll go about making a psu for both. probably using the C64 psu.) Quote Link to comment Share on other sites More sharing options...
Shum Posted July 10, 2006 Report Share Posted July 10, 2006 Hi,The 5vdc you measured is only the dc supply points to the ICs, however, there is a need to ensure that there are no bridges between tracks, especially between the IC legs. Also make sure that there are no bad or dry solder joins. The pic18F452 is susceptible to high frequency digital noise. Make sure you have the decoupling capacitors inplaced. A good power supply is also needed. When all these are inplaced you can plug in the optocoupler and the pic. If everything is ok, and your pic has a preloaded bootstrap loader, you can upload MIOS and later the application programme.Please read from the following web page if you intend to use the C64 PSU for the core and the SID module. http://www.ucapps.de/mbhp/mbhp_4xsid_c64_psu_optimized.pdf.Shum Quote Link to comment Share on other sites More sharing options...
docbrown Posted July 10, 2006 Report Share Posted July 10, 2006 Just FYI:Before you insert the PIC, make sure you do the voltage check that was recommended on the Core module page.. Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 10, 2006 Author Report Share Posted July 10, 2006 i checked for bridges between tracks after every soldering, so it should be fine. the solder joints look ok (except for the rectifier and regulator, where they are real ugly, but they seem to conduct just fine) the decoupling caps are in place although not as close as shown on the images as i didn't have any tweezers i could use for this and didn't want to burn my fingers. the psu is an ebs psu (for guitar effects rated 9V 500mA) and i ordered a pic with a bootstrap loader so i guess as soon as i connect the midi ports i should be good to go (i sure hope it works...) Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 11, 2006 Author Report Share Posted July 11, 2006 wohoo! i powered my core up, connected it to my motu traveler and got a nice steady blinking from my midi in port due to the upload requests. uploaded mios 1.9b: no errors. :D to do a little midi test i uploaded midi benchmark. seems to work great. on to the sid module! Quote Link to comment Share on other sites More sharing options...
Shum Posted July 12, 2006 Report Share Posted July 12, 2006 Hi,I am glad to note that you are progressing well. Wishinh you the best with the the SID module. By the way where did you buy your SID chip from and at what price?RegardsShum Quote Link to comment Share on other sites More sharing options...
l0calh05t Posted July 12, 2006 Author Report Share Posted July 12, 2006 i got my sid chip(s) on ebay. actually i bought a C64 but i talked a little with the seller and he suggested selling me a bunch of 6581's (two 6581's and a 6581R4AR) and a C64 psu for 15€ instead. Quote Link to comment Share on other sites More sharing options...
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