Wilba
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Posts posted by Wilba
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Thanks guys for your support. I ordered a new resistor, they are really cheap. To a noob like me it was quite surprising HOW cheap most standard electronic pieces are.
Be sure to check it is a "common pin" type resistor network... i.e. 5 resistors... and not the other kind with 3 separate, unconnected resistors.
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I wouldn't say it's malfunctioning, it's just not very good tolerance. I would expect regulated supplies to have less than 5% tolerance.
It should be OK for 8580 SIDs. If you don't get high enough voltage going into the 7809, you can try putting shunts in JBP to bypass the bridge rectifier. You must make sure the tip is positive (+) if you do that, but it will then put your 11.51V directly into the 7809 instead of losing ~1.2V from the two diodes in the bridge rectifier.
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LOL
Luckily, people who google image search for "SID synth" will find the results dominated by MIDIbox SID synths... my theory is it's because they are awesome.
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I know creatorlars does silkscreen, and he's in the US.
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If your aim is not to salvage a part (i.e. it's easily replaceable), then I advise sacrificing the part, chopping it into single pins which are then easy to desolder. You save a lot of time and it is less risk damaging the pads.
After you get the part out, removing solder from small pads is tedious and annoying. I often use a vice to hold the board vertical, edge towards me, so I can heat the pad with a soldering iron from one side while sucking solder from the other. Sometimes adding more solder to the pad can help, so there's more of a blob to be sucked out, i.e. if it's only a tiny bit inside the hole, this can be hard to get into an easily suckable state.
I have plenty spare resistor networks so just email me and I'll post you a new one.
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I've been very slack and never got around to uploading the PCB layout PDFs to assist with troubleshooting. I guess 95% of the time, I diagnose what's wrong and people just fix their solder joints or replace parts put in the wrong way :wink:
The troubleshooting section of the wiki now has PDFs: http://www.midibox.org/dokuwiki/doku.php?id=sammichsid#sammichsid_troubleshooting
So now you can see which tracks lead between the PIC and the LCD header. There are 4 data lines and 3 control lines, all on the top layer (red).
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If you are not getting text on the LCD (i.e. only "black bars") then that's the first problem you need to fix.
The PIC has MIOS installed so you should get the MIOS boot screen. Check the connections between the PIC and the LCD header, solder joints on both ends of the LCD header, etc. It might help to remove the LCD from the CS PCB so you can resolder the joints without the CS PCB getting in the way.
Perform continuity tests on all the pins of the LCD header, both ends, check there are no adjacent pins which are shorted, etc.
Also, check that you are getting some MIDI output, i.e. the single "upload request" sysex message... or just use MIOS Studio 2 and query the sammichSID (you need both MIDI In and Out connected and MIOS Studio ports configured correctly)... it should report that MIOS is installed on the PIC. This will help validate that your PIC is running and should be sending data to the LCD.
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A short beep when testing continuity between power rails is expected when there are capacitors between the rail. While the capacitor is charging up from the multimeter probe, it is fooled into thinking there is very low resistance. Once the capacitor is fully charged, there is no more current and the beep will stop.
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It's a wiki. Login using your forum username and password. Edit the page. Preview before saving. Don't make a mess.
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You may have shorts on the far left DOUT module (74HC595) causing the switch matrix to not work, buttons being pressed are thought to be other buttons being pressed. So check there first, then check solder joints on all the 74HC165 and check orientation of the resistor networks.
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Nice!
The list is not centrally maintained. Add yourself to the list!
http://www.midibox.org/dokuwiki/doku.php?id=wilba_mb_6582_builders_list
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I think the heat comes from both the 5V and the 9V/12V supply. They suck max. 100mA on the 5V, 40mA on the 9V/12V. So... P=IV... 0.5W + 0.36W (if 9V), or 0.5W + 0.48W (if 12V). I'm guessing... I don't really know the physics of this stuff :rolleyes: but that power has to go somewhere, doesn't it? So I guess it goes out as heat.
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Some fans are noisier (on the audio) than others. From experience, fans with LEDs are often noiser. Powering from J25 is best because it's before the regulators of SID audio voltage (i.e. the 12V or 9V supply to SIDs). Also, dropping the voltage to the fan somehow will keep its RPM low and the fan noise down too, but I don't have advice on that... I suppose sticking an 7805 between J25 and the fan would work... it doesn't need smoothing caps IMHO.
As for not powering SIDs... I can only guess that it's OK to leave out the 12V/9V supply to SIDs, since this is only powering the filter/amp inside the SID... let's say, I'd do it for my 6582A SIDs without worrying but for 6581 SIDs which spontaneously die on me even when packed in an antistatic tube, I would avoid even looking at them the wrong way, let alone rob them of power. :rolleyes:
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They should work. For reference, I use Mouser part 511-M74HC595.
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If it's doing things just when your hand is near, sounds like some pins on the 74HC165 are floating (not connected) so your hand is acting like an antenna, channeling interference into that pin. It's a bit like the buzz you hear when touching an audio plug that's plugged into an amp.
Check there's no shorts between encoder/switch pins and the heatsink... check all the solder joints there, resistor network orientation, parts in the right place, etc.
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Using a 12v unregulated, 500ma power supply, with 6581 Sids.
NO! You need REGULATED 12V DC for 6581 SIDs.
Certainly I've made this clear in the build manual. You should also not have inserted 6581 SIDs unless you get exactly 12V on the points marked 12V. Seems unlikely to have happened with unregulated power supply.
Most likely your other issues are due to too much current load, causing the internal voltage regulator to fail, causing the PIC to sometimes not boot and/or other stuff not working.
Remove SIDs immediately. Get everything going again WITHOUT SIDs. Get a regulated 12V DC power supply, preferably more than 500mA (to be sure) but a 500mA one will work.
Also turn down the LCD backlight brightness to half-way or less. This reduces current load, so when SIDs are eventually put in, you won't go over 500mA. Note SIDs each take 100mA on the 5V supply! So to balance it, the LCD should be drawing ~100mA to keep it all around 300mA or so.
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I haven't looked at the Eagle brd file (I can't even load it), but I can confirm both YAC512 should have VSS connected to ground, and on the OPL3 module itself, they are both connected to the ground plane. Maybe because those chips are mounted on the bottom makes it a bit confusing? i.e. pin 2 (VSS) is one pin up from bottom left corner.
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Mebbé we all make spam off fur of £1 nao?
Yeah, but has anyone really been far even as decided to use even go want to do look more like?
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The negative green LCDs I sell are high-power. Set JBL to 12V and put shunt in JR4, set brightness pot to half-way and no more. That will keep the total current load low enough for a 12V AC 500mA power supply. Any higher and the input voltage will sag, the voltage regulators won't have high enough input voltage to regulate 9V and 5V, and the PIC won't boot.
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You could cut off the DIN/DOUT section from the bottom and it would just fit :wink: But whether there would be clearance between the PCBs is another issue. You have to mount the PCB pretty high due to the extrusion at the back.
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Also, sometimes a C64 PSU has the 5V pin on the other side of ground. It is safe to connect both those pins together on the socket side (this is what I did on MB-6582 PCBs).
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Well, it is in the UK... they tax the crap out of everything going in, and then he probably had to pay £100 for the wind-generated electricity he used to solder it together. :whistle:
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Cool!
Where did you get the LCD?
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Wilba uses and recommends LEDs from Mouser, parts 638-204GD and 638-204ID
Excellent diffused and bright light at low currents.
20000 sold, never a complaint. :wink:
my new GM5x5x5 in a 19" rackmount enclosure
in MIDIbox of the Week
Posted
Awesome.