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Posted

Hi,

 

i've finally built my sammichSID, which has been waiting in it's package for quite some time now. after soldering i measured the voltages between various points, with success. so i happily inserted the minimum amount of ICs (left out SIDs and banks) to connect the whole thing with MIOSStudio. I connected the midi cable, power supply, switched on and followed the building instructions of this step.

 

MIOS Studio could successfully connect to the core and received the upload request. The manual says i should see a MIOS welcome message on the LCD after installing the PIC. But all it shows are the well known "top row of full recangles", exactly as before without inserted PIC. Even after successfully installing the SIDv2 Application via MIOS Studio the display does not show anything beside the rectangles. While rebooting the LED-Matrix show a kinda weird "animation", but i think thats normal behaviour? (it does that too, while formatting the bank ICs - while LCD still shows nothing of interest).

 

Another problem: how hot should the heatsink and SIDs become? I have inserted them to try if i could at least use the sammich without the LCD for now. After a short amount of time the heatsink and SIDs become warmer and warmer. Not as hot to burn your finger while touching, but hotter than i expected. Is this normal? I checked the voltages on the SIDs like described in the manual: it says there should be exactly 9V between pins 28 and 14. I measured something aroung 8.6V. Is this "exact" enough?

 

LCD: "white on blue" low-power LCD (included in kit)

SIDs: 2x 6582A (included in kit)

Power Supply: DSA-0151A-12 UP (12VDC 1.4A, unregulated)

USB/Midi Interface: Neusonik uMIDI/O22

 

Since i'm more of a newbie in the field of electronics (soldering is ok, but not as much theoretical background), i hope someone can help to debug this problems.

Thanks in advance.

Posted

Hi,

 

the LCD behaves this way if:

1) it isn't connected properly (e.g. because of bad solder joints)

2) it isn't compatible to the 4bit access mode (no problem if you got the LCD from Wilba)

3) you haven't installed MIOS yet - this has to be done before the MIDIbox SID application will be installed

 

If you are unsure, just install again the latest (public beta) versions which are linked here: 

 

But you are saying that the LEDs are somehow animated - this is the normal behaviour during boot.

After ca. 3 seconds the animation will stop, right?

If it does stop: then MIOS and the application has been installed correctly - the error must be somewhere else (probably topic 1)

 

 

It's normal that the voltage regulators get hot, therefore they have a heat sink

 

Best Regards, Thorsten.

Posted

Thanks for your fast reply.

 

Yes, the LED animation stops after about 3 seconds. Only directly after inserting the bank ICs and rebooting, the animation runs for a longer duration.

 

Is there any concrete target temperature to be expected for the heatsinks and SID chips, so i could check if their temperature is in acceptable range and not way too hot?

 

@3: i thought MIOS is preburned/installed on the PIC? Would MIOS Studio even install the SID application if MIOS isn't there?

@1: i will check that

 

Best regards

Posted

@3: not relevant anymore, because you confirmed that the animation stops after 3 seconds... MIOS is installed

@1: the most likely reason why the LCD doesn't work

 

No, there is no concrete target temperature - the voltage regulators get hot, that's normal!

 

Best Regards, Thorsten.

Posted (edited)

I was able to successfully use the sammich with my DAW to generate nice sounding audio output! So at least it's currently working in "headless" mode. as far as i can see, the control surface is working, too. :-)

 

I have tested the connections between the PIC/GND/etc and the LCD connector/interconnection stage (tested for continuity) which seem to be fine.

could there be a problem with the LCD itself?

 

Before installing the PIC/ICs, while measuring voltages on the PCBs i accidently shorted pins 5V and GND (on the LCD) with one of the multimeter's test leads. The display went dark and comes back to "life" immediatly after releasing the short. Could i have damaged some kind of controller unit of the LCD?

 

Best regards

 

 

Edit: added "(on the LCD)" to specify shorted pins

Edited by henk
Posted
Before installing the PIC/ICs, while measuring voltages on the PCBs i accidently shorted pins 5V and GND (on the LCD) with one of the multimeter's test leads. The display went dark and comes back to "life" immediatly after releasing the short. Could i have damaged some kind of controller unit of the LCD?

 

That's very unlikely, because this caused a short circuit for the complete unit.

It's possible to damage a LCD if it's plugged in the wrong direction into the socket, but I guess that you haven't done this.

 

Which LCD are you using exactly?

(I remember that Wilba provided two different types)

 

Best Regards, Thorsten.

Posted (edited)
Which LCD are you using exactly?

(I remember that Wilba provided two different types)

 

Right. I have the "white on blue / low power" (5V, 25mA) type.

Text on backside: DISPLAYTECH 202A / 94V-0 CP5 KW

 

post-5190-0-46215000-1404681606_thumb.jp

post-5190-0-71876700-1404681613_thumb.jp

 

Best regards

Edited by henk
Posted

This LCD should work.

 

I would propose to install the lcd_interconnection_test, which can be downloaded from http://www.ucapps.de/mios_download.html

 

See the README.txt of this .zip package for test procedure details.

 

Note that D0..D3 won't output the voltage, because PIC18F4685 accesses the LCD in 4bit mode

 

Best Regards, Thorsten.

Posted (edited)

Hi Thorsten,

 

I just finished your proposed test.

 

The first measurement has taken place with detached control PCB. I measured the soldering points of the connector socket on the backside of the base PCB.

post-5190-0-47350400-1404763886_thumb.pn

 

For a second measurement i have added the control surface PCB and measured the soldering points on top of the connector, directly on the LCD. Since some voltages have changed quite a bit, i have measured the backside of the base PCB again (in some cases) and could verify the different voltages with attached control surface PCB there, too.

post-5190-0-38791600-1404763894_thumb.pn

 

 

with control surface/lcd detached

  • RS off = 0,09V
  • B- = 0V
  • D0-D3 = always 0V

 

with control surface/lcd attached

  • RS off = 0,09V
  • B- = 1,78V
  • D0-D3 = either 0V or 5V

 

Best regards.

Edited by henk
Posted

All values are in the expected range, even B- (which is the backlight voltage)

 

I've no idea what else could cause the problem.

 

Best Regards, Thorsten.

Posted

hm k... then i will check the soldering points on the LCD again. maybe even simply resolder that part or finally try a replacement LCD. Maybe there is really something wrong with my LCD. If the values are in their expected ranges like you said, then the problem has to be the LCD/LCD soldering...

 

thank you for your help! :-)

Posted

Hi again,

 

I resoldered the LCD without success. It is still showing only the first row with all filled rectangles.

I played around with the two brightness and contrast thingies on the side and noticed, that i could only see these rectangles if the contrast controller is all the way "down". if i slightly (maybe up to 5%) rotate it up the rectangles fade away, so the display only shows the blue background "light". the brightness control barely has any effect: the brightness only changes slightly while turning the control from min to max.

 

I am kind of stuck now, has *anybody* any idea to try/measure?

Could the power supply be a problem? (see initial post)

 

thanks

Posted (edited)

Hi

If you hear any sound (clear sound) then power supply is ok. I think you can check that there maybe invisible shorts - these thin like hair. Anyway also check other side - i mean uC and contacts here. If nothing help then simplest way to be sure is to check your LCD in another device or use another LCD in your setup.  Maybe you have some friend or someone who can "rent" you LCD just for while. As i wrote in similar problem - topic, you may even buy lcd. These 1602 on ebay from China cost now 2$ incl shipping - i think youre rich enough;) If not sell then few bottles;) Not nice is only time to wait.

Cheers

C_04 

 

P.S. Try maybe to solder both sides of LCD if metalization through holes could weak.

Edited by C_04
  • 4 years later...
Posted

Hi again,

I just wanted to say thank you to everyone involved in this troubleshoot thread, thanks for all your help!
Last week my sammichSID has finally been completed, after replacing the propably broken original LCD.

Everything is finally working as expected.

Sorry for this late reply and thread necromancing.
This thread can now be flagged as "solved".

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