Additional Build Tipps / Feedback

Nasrudin

Hi all,

I just finished the assembly of my LXR and want to share my experiences Overall, the build is very easy. However there are a few things which are a little bit tricky to handle, especially if you are a newbie to soldering.
Following tips worked for me, i hope they help you too.

Nr.1: Use the provided bubblefoil as your building- /soldering underground. This will protect the enclosure from scratches and prevent resistors, screws etc from falling over the table. Also, you dont ruin your kitchentable if you accidentally produce tin solder splashes (your mom /dad / boy-/girlfriend / husband / wife /whatever will thank you xD).

Nr.2 When it comes to soldering the resistors near the USB jack, cut the wire first, then add tin solder carefully. this way the USB jack can be placed plain to the board.

Nr.3 If you have some jumpers laying around, do not solder the bridge in. Instead, solder in a pair of jumper pins and connect them with your spare jumper. This way you can add a power switch later without having to (de-) solder on the board again.

Nr.4 Aligning the LEDs is the trickiest step in my oppinion. Put them in, then rotate the board at 90 ° and solder 1 pin. Now bend the LED until it stands vertical on the board. Now solder the second pin.

Nr.5 After soldering the LCD connector, "carefully" remove the plastik spacer and mount it upside down. this way, the u-profile of the spacer leaves more space for tin solder bubbles on the surface of the board.

Nr.6 Just in Case you dont know how to update the firmware (didn't find anything with forum search): Load the binary on the SD card and put it into the slot. Now press and hold the encoder right from the display and power on the LXR. you can now observe the firmware update via LCD and the sequencer LEDs.

Some suggestions for the next batch:

* the LEDs near the voicebuttons should be moved a little bit ahead from the switches.
* In my case, some of the switchcaps wont stick on the switches. Maybe caps from another source would fit better.

Regards,
Nasrudin

julian

thanks for the treport!
I think I will include some of the stuff in the assembly instructions.

paul_v

A little hint on how to "fix" the button caps without actually gluing them irreversibly:

A smaaall piece of insulating tape (or something like that) does the trick. 

Don't let it overlap the grey, fix area of the button! 

toneburst

Just finished my build yesterday. Wish I'd read Nasrudin's tips now, though!

Just to echo what Nasrudin says: the LEDs for the voice selector buttons should definitely be moved a little further away from the switches in a future revision of the board. I ended up having to file one side of each of the LEDs in this section in order to get them to stand up straight.

The components around the inductance resistor L1 are very tight, and I don't like the way the pads for L1 are narrower than the actual component so you end up having to bend one of the legs around and making the resistor 'float' above the board. I don't know if there's any way round this, routing-wise, but it might be worth mentioning something about it in the Assembly Instructions.

There are also a couple of pads on the bottom of the board that are far too near to the sockets for the mainboard. One instance of this is flagged up in the notes, but there's another pad which is not mentioned, that is equally hard to solder without melting the plastic of the mainboard socket.

There are quite a few instances of very closely-spaced pads. I can't remember off the top of my head were exactly, but again, it might be worth some warnings in the instructions. I can imagine relatively inexperienced builders accidentally bridging some pads in various places.

It would be nice to have a larger photo showing the LEDs, as it's hard to tell what colour is supposed to be installed where from the tiny photo in the Assembly Instructions. I managed to work it out in the end, but it could definitely have been clearer. I know from experience that desoldering LEDs isn't much fun, so this should be made as clear as possible in the documentation, I think.

The most challenging part of the whole build for me was getting the case together. I'm still not happy with the way it bulges out in various places, and I ended up having to loosen the 5 small standoffs on the top of the control board in order to be able to screw in the black screws. The whole case now creaks when moved. They seem symmetrical, but do the case side panels have to be a particular way around in order for the whole thing to fit together properly, maybe? If there is a 'best practice' method for assembling the enclosure, it might be a good idea to add that to the documentation, too.

The default setting for the HH voice with no SD card installed seems to have an infinite release. I didn't have a spare SD card when I was testing the LXR last night, and I found when I'd triggered a HH, it just kept sounding, and the only way I could get it to stop was to restart the unit! More generally, is it worth setting all the voices to more useful (or at least conventionally drum-like) settings by default, so that you can get a sense of what the machine is capable of, even without an SD card installed? Might be something to consider for a future firmware release. I'm assuming this is already the case with a properly-formatted SD card with the right files on it in the slot.

All in all though,  I've found the documentation and quality of the board to be top-notch. It took me most of the day to put together the kit, but I was also listening to the tennis, and had to go out and source a replacement soldering iron when my old one died half way through the build! Everything worked perfectly first time!

One last observation: It might be worth adding a note in the Instructions to the effect that when testing the board before installing the display, but after fitting the mainboard, the LXR takes several seconds to start up, before there are any signs of life. I actually panicked at this point, because nothing appeared to be happening. It turned out I just hadn't waited long enough, but because the LEDs had lit up almost immediately in my previous voltage test, before I installed the mainboard, I assumed the same was supposed to happen with the mainboard installed, and when it didn't, I thought something was wrong.

Anyway, looking forward to getting to grips with this exciting machine! Well done Julian!

a|x

toneburst

To be fair, it does clearly say in the Assembly Instructions that you should install the SD card, properly formatted, with the correct files on it before starting, so maybe that last point doesn't really need addressing. I'm just too impatient, I think..

a|x

julian

it is also on the buglist (no init sound without SD card)
but the other points are good hints.
I'm trying to put an assembly instruction for the case online this week! so far the cases i've build di not creek or need excessive bending to screw together... :-/

toneburst

@julian cool

Re. init sound: Ah, sorry. Should have looked at the buglist.

Re. the enclosure: It's weird, I've made quite a few projects using Frank's cases, and never had such problems getting them together- none of the holes seemed to line up as they should, for some reason. The only parts I could potentially have got the wrong way round are are the side-panels. They obviously have slots that need to be towards the back, but there are still a number of different ways they could be fitted. Having said that, it was the holes in the bottom and (particularly) top panels that didn't line up, leading to much frustration and not a little swearing as I was trying to put the thing together late last night.

a|x

fcd72

Can you post a pic of the Panels? If it fits now its ok. I have sometimes (1 in about 700 cases) an occurance of misaligning i cant explain....

toneburst

@fcd72 I'm at work right now, but I will post a photo when I get back home.

a|x

FLOz

I mounted successfully (=straight) the LED like this:

- insert all the LED in the PCB (easy)

- mount the front panel

- return the complete machine on a plane working face (the front panel has tendency to bend)

- push the LED against the front panel in order to have them straight

- solder one pin for each of them keeping them straight (not easy)

- adjust them if necessary

- finish to solder.

I think it more readable/clear with the LED lying directly on the front panel and there is no collision anymore with push buttons.

FLOz

For L1 I would advice to mount it à la x0xb0x (i.e. like the resistors on this picture: http://www.ladyada.net/images/x0xb0x/fab/vco/sawprobe.jpg).

shiftr

I love those pictures! But i like it better when the Leds get a bit vague inside the case. Makes it look a bit more magical i think.

julian

@shiftr maybe install a small fog machine inside the case then!

shiftr

It would be too cool if it would constantly emit a little smoke through the vent holes!.. :-D

fcd72

Märklin had these small fog generators for ht HO Railroads....

Looks like Conrad is our friend this time ;-)

julian

and the great thing is the smoke comes with lemon or spruce smell! =P~

fcd72

@julian

can you please include a dedicated transistor for about 200mA and include a dedicated CC in the Firmware?

julian

A little hint on how to "fix" the button caps without actually gluing them irreversibly:

I'll borrow these pics for the assembly instructions if you don't mind

shaduz

I've finished my unit yesterday, here's my build log - it might be helpful in case you need to troubleshoot your LXR 

(and thanks, Julian, for the patience and support in the last few days!)

July 4th, 2013

unit received! After three hours of soldering, everything is ready for the final test! 

Unfortunately there is no connection between the frontpanel and the mainboard. The UI is working properly, but when I hit the start button nothing happens, and I'm not able to enable/disable steps.

July 5th, 2013

Alright, there should be a short somewhere, let's find it! First of all, I reflowed all the soldering joints, then checked the following with my multimeter:

- 5V between pin 8 and pin 16(+), on every 165 and 595

- 3.3V between pin 1(+) and pin 8 of U4 (4050)

- 5V between pin 10(+) and 11 and between 10(+) and 31 of the ATMega

- 5V between pin 1 and 2(+), between 2 and 5(+) and between 2(+) and 16 of the display connector

- 3.3V between pin 11 and pin 21 of the ATMEGA(reset line for the mainboard)

- 5V between pin 11 and pin 9 of the ATMEGA (reset line for the ATMEGA)

- continuity test between: ATMEGA-1:OLED-11, AVR-2:OLED-12, ATMEGA-3:OLED-13, ATMEGA-4:OLED-14, ATMEGA-25:OLED-6, ATMEGA-26:OLED-4

- continuity test between: ATMEGA-14:P1-9 and ATMEGA-15:P1-11 (P1 is the mainboard connector on the right, if you look from the top of the front panel)

- continuity test between: ATMEGA-7:P1-1

- continuity test between: ATMEGA-5:U4-7, ATMEGA-6:U4-3 and ATMEGA-8:U4-5

- continuity test between: U4-2:P1-5, U4-4:P1-7 and U4-6:P1-3

- no shorts between all the P1 pins (excluding: P1-21:P1-22, P1-23:P1-24 and P1-25:P1-26)

- no shorts between all the P2 pins (excluding: P2-1:P2-2, P2-3:P2-4, P2-5:P2-6, P2-7:P2-8, P2-9:P2-10)

- if no audio jack is plugged into the synth, there will be a short between pins 9, 10, 12 and 14 of P2

At this point, I turned on the synth pressing down the encoder, to start the firmware update: success! (the day before I had an error in phase 2/2, "no ack")

Then, after reboot, the synth was still not working:

- UI was responsive for a while, but still I couldn't set steps or start the sequencer

- After a few seconds the display started to show weird characters :-?

July 6th, 2013

- Connected the USB port, I can see the USB MIDI port in my sequencer! The synth responds to MIDI notes both from the regular MIDI interface and from the USB MIDI interface, but when I start the synth with the SD card inserted, I get random sounds after every reboot (hmm... interesting). 

- Without the SD card I always have the same init sound after every reboot (must be the one hardcoded in the firmare)

- MIDI CCs are also working!

- The frontpanel is still not working: weird chars after a few seconds, sequencer doesn't run.

July 7th, 2013

 - Removed the mainboard and connected manually just VCC (P1-23 or P1-24), GND (P1-25 or P1-26), ATMEGA-14 ( to motherboard TX3) and ATMEGA-15 ( to motherboard RX3) - had to bend the ATMEGA pins to keep them out of the socket. Still no success, communication between AVR and ARM is still messy.

 - Enough for today, it's sunday after all... time to grill in the park

 

 July 8th, 2013

 - Checked R6, replaced C7, re-checked again, just to make sure there are no spurious/random AVR resets. Still no success.

 - Wait a minute... maybe... THE QUARTZ!!!!!! :-B

Ok, let's replace it, maybe I somehow damaged it while soldering... ... ... (desoldering the quartz) ... ... ... (almost destroyed one pad of the quartz, shit!) ... ... ... solder new quartz........

 - Re-try firmware update... worked nicely

 - Reboot the synth... and voila'! WORKING :-))  

Time to play a little bit :@) ;

cheers,

shaduz

julian

thanks for the résumé!
I never had a quartz fail before... this was really a hard one. But I'm really glad you finally got it working!

paul_v

A little hint on how to "fix" the button caps without actually gluing them irreversibly:

I'll borrow these pics for the assembly instructions if you don't mind

Yes. I'm pleased to help. I did some more (and higher resolution as i resized them for the forum). i'll drop you an email this evening

toneburst

@paul_v great tip re. the button caps. Just tried it on one, and it works really well!

a|x

toneburst

Ah, another thing in the build guide I remember confusing me when I build my LXR:

This picture

It's not at all clear what you mean by the 'orientation' of the jumpers. I wasn't aware they had a right and a wrong way around. Or do you mean check they're the right way up? Surely they'll work fine whichever way around/up they are (albeit they're slightly trickier to remove if they're upside-down).

I think that needs clarifying

a|x

julian

No, what is meant is the way the jumpers are set to the pins.
On the 2x4 header it is quite obvious, but on the 2x2 header you could put the jumpers on like this || or like this =, whereas the 1st option would just short out the 2 output channels and not produce any sound.

toneburst

@julian Ah, I seeeeeeeeeee. That makes sense, now. It might be clearer if you just said something like 'make sure the jumpers are installed as below <picture>'.

a|x

SG88

Hi,

Completed LXR today - my first self build, feeling elated as I chew on victory candy.

Some feedback, probably more relevant for noob builders like me:

1. The mysterious 'bridge' at the very beginning - yes, it's just a bit of wire that you trimmed from a resistor or something - there's no context for this in the build info, it's kinda assumed that you know what a bridge is, I don't even know now (and don't care :0 ), except that it's just a piece of wire soldered across two points - hence 'bridge' - gettit? (I'll include a nice picture of a real bridge in my FINISHED post later).

2. There's a lot of stuff in the build guide about getting the display straight, fiddling about with the black plastic thingy, trimming leads to make sure the display lies flat etc etc - I worried and spent too much time on this and can't understand why? In the end I'm sure I used too much solder on the connector pins, didn't push the black thingy down far enough, and my display definitely does NOT sit flat on the board - but guess what? It looks great, is perfectly (I mean perfectly) readable, and rocks! Am I missing something? Will my display mysteriously fail or something later...

3. The one place I had trouble right at the end was with attaching the main board to the female connectors because I hadn't fixed them flush to the board at the beginning. This is an early step and should be emphasised in the build guide as one place where you definitely DO want the parts to be straight and flush. I ended up getting out the desolder braid out and having to coax one of the connectors into a straighter alignment with pliers (not pleasant) - even now I'm worried the main board may be under stress because of this...

4. The case - it would be nice to have a sticky link to some assembly instructions - I know there's a link somewhere in the forum already to the MI cases but after searching for 20 mins I gave up and just used The Force to figure it out myself, it's not hard, see below.

5. The case - there's some advice about 'keeping it loose' on the forum here - this is very important - in my build most of the stress was coming from the back panel where the various in/outs, power, usb etc have to be lined up with the panel cutouts - chances are, if your a noob like me, some of your in/outs etc may be a little squint - but trust me, as long as they are not off by a mile, just using a little patience and keeping the case screws/nuts loose, you will be able to prise the cutouts over your connectors then tighten up - overall I'm extremely pleased with the case - although I did get a strange assortment of panels which I'll post pics of later

Yum - this Victory Candy tastes gooooood!

julian

I'll try to include your tips in the next revised version of the build instructions. Since there are some small changes for batch 2 I have to rewrite them anyways over the next days. Then it will also come with a case assembly instruction.

thanks for taking your time to write your comment, very appreciated!

julian

1.)I added a picture and text explaining 'the bridge' to the assembly guide
2.) the problem is that if you use too much solder the display will be too high to fit under the enclosure afterwards. already had a customer who had to resolder the display when he wanted to assemble the enclosure.
3.)added a note to install them completely flat.
4./5.)added a dedicated illustrated step-by-step guide to the website http://www.sonic-potions.com/enclosureAssembly

The new assembly guide is currently in the proofreading stage and up soon.

borfo

Hey, the new "function:" notes in the build instructions are great.  Thanks for adding those.

SG88

Yes - ill have to re-read now so I can understand what I built

nightworxx

As Tim (Tooltime) already stated: "real men don't need instructions !"