Snoozr

Desoldered and replaced the vregs. 9V rail now gives about 9.03V so that seems fine. 5V rail now gives 6.7V. The new 7805 has 7.5V going into it, i.e., the Pin 1 to Pin 2 reading is 7.5V. The Pin 2 to Pin 3 reading is as before. I will upload some pics in the next post in case that helps.

Thanks Phil. So should I snip out the cathode, the anode or both? Also, based on your description of the right way to do it, the "right" reading of the above two was the 770 one. Of course, the real right way would be to snip out like you said. By the way, I tried putting the 1K resistor in J20 and J2 but this did not help. I also put my finger on there (bridging the pads) as kind of a 1M resistor. No change.

I have a diode checker on 1 of the meters. I have no idea what the units are. When I put the positive probe on the lead in the direction of current ("output") and the negative probe on the other side ("input"), I get a reading of -458. When I reverse the probes, I get a reading of 770. These numbers are pretty consistent across diodes.

I had a 470 ohm resistor which I inserted in J2. This dropped the 5V line's voltage to about 7.5V as measured both at J2 (measured across the resistor) and at J4 (sanity check). For the Wilba test, I removed the resistor. I tested the 7805. Ground to "Leg 3" (the one on the right as you look at the board with the power switch away from you) gave 8V. Ground to "Leg 1" is around 8.95V depending on the meter. For the 7809, Ground to "Leg 3" (the one on the right as you look at the board with the power switch away from you) is about 11.85 and around 9.5 on "Leg 1". The whole 9V rail seems to have improved as a result of the insertion of the resistor. I decided to stick the resistor in J20 since J2 (oddly) seemed to clear up the 9V line. Hence, resistor ih 9V might help 5V line. Putting it in and taking it out brought the 5V line closer to 7.1V, a small improvement. I will see if I can scrounge up a bigger resistor and try to keep pushing the voltages back to spec.

From Wiki: I would be in for 20 black/white.

Also, JBP has the 2 shunts as per the 6581 build instructions.

Thanks Nils. Here are some updates. These are all correct polarity except for C6 which appears to be non-polarized (monolithic and no + sign on the board). They are both correct. JP is set for 6581. I am using the PS-1251 regulated 12V power supply from All Electronics which was mentioned here on the forum. The output of this is 12VDC as checked on meter. The output across C6 is still 12V. The output across J20 is still 10.5V. The output across J2 is still 8V. I checked these voltages with two meters, so these numbers are good. A few other things - I touched up a few solder joints around this part of the board. No obvious bridges or shorts. Also I happened to have labeled the 7809 and the 7805 on the visible side and so I can confirm they are correctly stuffed. I checked the small heatsink for the 7809 and it has no connectivity with the rest of the board. However, the large heatsink is connected to ground. I don't know if this matters or not. It is not connected to any of the 5V, 9V or 12V lines. This is probably not the issue but it's the only thing I can think of. There are four holes for C6, two inner holes and two outer holes. The Build Guide shows the leads of C6 going into the outer holes, and that's what I've done. Some of the solder dribbled over into an inner hole and I am having a hell of a time getting it out. There are a number of other points on the board where this issue crops up. I am actually a passable solderer and have yet to have a soldering issue come up on any of my builds, plus I can see some places on the board such as C7R where the inner hole and outer hole appear to share a common metal border by design. So I assume this isn't an issue because the inner and outer holes are already bridged, but just thought I would mention it.

PS - I followed the ucapps schematic because I read somewhere that the sammichSID follows this.

Funky in a bad way unfortunately. sammichSID voltages are too high. 9V rail is reading about 10.5V. 5V rail is reading around 8V. 12V rail is fine. I followed the Sid V2 optimized PSU schem at http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf J1 (input plug) fine (fine means I can get 12V across the part). Rocker switch is fine. Bridge rectifier X1 is fine. Large cap C5 is fine as is little C6. After that, something happens. From the schem I assume (maybe) that next up is the little electrolytics C4 and C10 and the little radial caps C3 and C9. However, by the time it gets to these, the voltage has gone weird. Voltage is also wrong at the 7809 and the 7805. Read all the voltage Sid threads but couldn't find any smoking guns yet. I'll give the solder joints of all the above a once-over but in the interim if any ideas crop up, let me know. Thanks.

Watch out for SammichCat :)

Dear Santa - pleaze haz SammichMB-808 beneath mai tree next year. I b gud boy! :whistle:

Wear can eye sign up for de sammichFM - must have moar Sammich. :frantics: Eye's hungry. Kthxbai!1

If you have some to sell, give me a PM with price. I am looking for 10 or more. Thanks.

Great stuff! Gotta go run and get some Dramamine now though :)

Awesome! Love the what-patch-is-that moment :)

Just my two cents (because I am not very knowledgeable), but I think you might want to start checking the line backward from the audio jack. There is a schematic around here which tells you which pin goes to what - have a search. You will need to report back more information about what does appear to be connected and what does not. Check for shorts. Report more information and someone might be able to help you. You've identified the problem which is signal does not travel from Sid to jack, so now you will just need to start narrowing that down.

Haha - it's all good. I learned some new stuff and I got a great synth. Thumbs up for Midiboxes!

I had absolutely no skills either but I managed to complete an MB-6582 (with patience and some kind help from the forum folks). Any skill required for this project is learnable. The Sammich is dramatically simpler from what I understand (haven't started on mine yet). You can do it, and it's very rewarding. It's not just an instrument but also an accomplishment. Good luck :clover:

Great walk-through - would have made my build go a lot faster. I nominate this for a sticky in the MB Sid section. Not everyone will find it over here.

Lol. :thumbsup: Case closed. I had previously applied electrical tape to the top part of the LCD so as to protect the LCD inputs from contacting anything. I decided to remove the LCD again so as to similarly apply tape to the bottom portion. Once it was removed, I powered up the little guy and there was no problem. Ka-ching. I applied electrical tape to the underside of the CS where Select 1-5 were and re-attached the LCD. Powered up and the problem was gone :D Select 5 does a number of important things like Save and Detune so I am glad to get that functionality, plus the perma-blinking matrix was cool for a while but started to get distracting. THANKS WILBA!!! :sorcerer:

I'm getting 5V except for on the bad line which is 0V. Procedure was take out U20, touch red lead to JD5 solder joints, touch black lead to GND. Repeated procedure with U23 out as well and got same result. I'm getting about 13K on the Sanwa, except for on the bad line which seems to have very little resistance (needle flies over and pins to zero). Procedure was take out U20, touch red lead to +5v, touch black lead to JD5 solder joints.

Thanks - these are all aligned as you mentioned. I checked this and the adjacent ones and the ones on the IC socket as well. They looked fine but I touched them up anyway. The problem is still there. On checking voltages with the power on, I've cooked a few things to date doing this so I want to be extra sure I know what I am doing. It sounds like: remove U20 and U23; touch unconnected pin of a given button such as Mod O2 PW with the red lead of the multimeter; touch IC socket associated with JD5 D4 with black lead of the multimeter; verify 5V on multimeter. Yes, that's right - except for the Env Sel button. For Env Sel the unconnected side is the side away from the diode. I don't know if that's a clue or not but I rechecked everything and that's the unconnected side on mine at the moment.

For what it's worth, your LCD may have come with a little tech sheet -- it might be worth reading through this. My experience has been that LCD's are a bit delicate as I've cooked two so far.

I experienced this problem too. I could be wrong but my thoughts were that the stranded wire might not be as idiot-proof as solid copper "hook up" wires in the sense that solid core might tolerate metal fatigue better. Hence, beginners might have a bit more luck with solid core, although you would have to cut and strip each one individually and identically. I did not check that solid core would fit in the holes - that would be another consideration. Knock on major wood that I don't have to repair this again. I had to pick out little strands while desoldering, I lifted two pads, etc.

In the course of using my MB 6582 it's become clear that the above problem is related to some other problems. In addition to the Mod O2 PW & Mod Src 5 buttons, the Env Sel and the Select 5 are all out. These are all on a single line - the JD5 D4 line. I've tried a number of things to troubleshoot/fix this myself, including: * Removing the IC as Wilba mentioned above and testing all 4 buttons individually at the appropriate IC socket. All buttons, when pressed, get connectivity with the socket and are disconnected otherwise. * Replacing the IC with a new one. Didn't help. * Checking at numerous places along the line for connectivity - everything's fine. * Testing JD5 D4's neighbors for a short with D4 - none found. * Spot checking around for shorts - none found. Since the Matrix Col. 5 & Row 5 lights are blinking, the MB-6582 must be assuming the Mod O2 PW & Mod Src 5 buttons are pressed, even though the testing above in Bullet Point 1 indicates that it should not be assuming this. It's possible that the MB-6582 is also assuming that the other 2 buttons are the line are pressed as well - however, there are no flashing lights that would reveal this. I'm running out of ideas - the only thing I can currently think of is maybe a MIOS problem but this seems extremely unlikely as I used the default package. Thanks gang.