Troubleshooting LCD-display?

[oberg]

I'm trying to build the MB-SID - this far I've finished my first (out of 4) Core/SID pair and the optimized recycled-C64 PSU-circuit. My PICs are burnt (bootstrap 1.1b) with the JDM module without much trouble (the voltages on the JDM didn't reach the levels stated on the ucapps.de webpage - but it seemed to work up just fine anyway).

So far so good...

When I hook up my Core-board to MidiOX I get the bootstrap upload request but I don't seem to be able to upload MIOS. I haven't done the LED-troubleshooting TK describes yet since I was planning to get the LCD working first to see what I'm doing.

BUT - right now the LCD gives me nothing. No blocks, no nothing. The wiring should be good, since I've used my multimeter to check connections from the solderingpoints at the LCD to the corresponding legs on the PIC.

I'm worried that I might somehow have burned my LCD - but before I go out and buy another one. Do you have any suggestions on further troubleshooting?

Thanks.

The LCD is a 2x20 OLED "PDC2002M".

specs: http://www.delta-opto.com.tw/PRODUCTS/PDC2002M_spec.pdf

[oberg]

I'm trying to build the MB-SID - this far I've finished my first (out of 4) Core/SID pair and the optimized recycled-C64 PSU-circuit. My PICs are burnt (bootstrap 1.1b) with the JDM module without much trouble (the voltages on the JDM didn't reach the levels stated on the ucapps.de webpage - but it seemed to work up just fine anyway).

So far so good...

When I hook up my Core-board to MidiOX I get the bootstrap upload request but I don't seem to be able to upload MIOS. I haven't done the LED-troubleshooting TK describes yet since I was planning to get the LCD working first to see what I'm doing.

BUT - right now the LCD gives me nothing. No blocks, no nothing. The wiring should be good, since I've used my multimeter to check connections from the solderingpoints at the LCD to the corresponding legs on the PIC.

I'm worried that I might somehow have burned my LCD - but before I go out and buy another one. Do you have any suggestions on further troubleshooting?

Thanks.

The LCD is a 2x20 OLED "PDC2002M".

specs: http://www.delta-opto.com.tw/PRODUCTS/PDC2002M_spec.pdf

[oberg]

I've done some measuring and VSS is grounded, the VDD and VBT seem to get the voltages they should. The rest of the pins show low voltages which seem ok. (All according to the LCD-datasheet). All the pins and wirdes are connected accordingly to the wiring shown in mbhp_lcd.pdf.

Strange...  ???

Since I get the bootstrap upload request over MIDI I guess that my PIC is alright. But is there some other critical component of the Core-module that could be wasted that would make the LCD go out? (I'm thinking oscillator? Or can I assume that the oscillator is ok since I get the upload request?)

[oberg]

I've done some measuring and VSS is grounded, the VDD and VBT seem to get the voltages they should. The rest of the pins show low voltages which seem ok. (All according to the LCD-datasheet). All the pins and wirdes are connected accordingly to the wiring shown in mbhp_lcd.pdf.

Strange...  ???

Since I get the bootstrap upload request over MIDI I guess that my PIC is alright. But is there some other critical component of the Core-module that could be wasted that would make the LCD go out? (I'm thinking oscillator? Or can I assume that the oscillator is ok since I get the upload request?)

[pay_c]

Perhaps your LCD needs negative Voltage for Contrast...

did you try to put the voltage for contrast the full way up / down? Does it get black anyhow?

If not try following: Use a 1,5V AA battery. Hook the + to the ground of the core and the - to the contrast Pin on your LCD. Should at least get black now - or even characters and stuff.

It´s pretty hard to wreck a LCD, so I don´t think this is the reason. Greetz!

[pay_c]

Perhaps your LCD needs negative Voltage for Contrast...

did you try to put the voltage for contrast the full way up / down? Does it get black anyhow?

If not try following: Use a 1,5V AA battery. Hook the + to the ground of the core and the - to the contrast Pin on your LCD. Should at least get black now - or even characters and stuff.

It´s pretty hard to wreck a LCD, so I don´t think this is the reason. Greetz!

[oberg]

Thanks for your suggestions!

On my LCD they don't call i contrast but rather "brightness" (pin 3 "VBT" on my LCD, V0 on Thorstens drawings). I've tried adjusting the 10k-contrast pot without any signs of life from the screen. The batterytest also failed (+ to ground - to pin three, and vice versa).

My plan now is to buy another (cheap) ordinary LCD (no OLED) to see if my problems are within the Core or the screen. Any other suggestions?

[oberg]

Thanks for your suggestions!

On my LCD they don't call i contrast but rather "brightness" (pin 3 "VBT" on my LCD, V0 on Thorstens drawings). I've tried adjusting the 10k-contrast pot without any signs of life from the screen. The batterytest also failed (+ to ground - to pin three, and vice versa).

My plan now is to buy another (cheap) ordinary LCD (no OLED) to see if my problems are within the Core or the screen. Any other suggestions?

[pay_c]

I think I would do the same...

Just also google for some datasheet for your LCD there. Perhaps there´s something (like the needed voltage or similar).

Greetz & good luck!

[pay_c]

I think I would do the same...

Just also google for some datasheet for your LCD there. Perhaps there´s something (like the needed voltage or similar).

Greetz & good luck!

[oberg]

Got a new LCD today.

Soldered it in place - got a flash of the famous black boxes flickering - and then nothing. It just wont come alive again.

I think I'll build a new Core module to see if I have more luck with a new one.

B-B-Boring...  :P

[oberg]

Got a new LCD today.

Soldered it in place - got a flash of the famous black boxes flickering - and then nothing. It just wont come alive again.

I think I'll build a new Core module to see if I have more luck with a new one.

B-B-Boring...  :P

[pay_c]

Sounds like some short somewhere (or mixed up 5V/GND). Perhaps you can find it before starting all over (nearly).

*Sigh*

Good luck anyhow!  :)

[pay_c]

Sounds like some short somewhere (or mixed up 5V/GND). Perhaps you can find it before starting all over (nearly).

*Sigh*

Good luck anyhow!  :)

[Guest marr]

I was looking over the schematic pdfs last night and noticed a little warning about the transistor to the "LCD contrast" input..

it says something like "if you dont use the specified cap your BCE pins may be different..". Are you sure you have the right pins connected to the right places? I'm not sure what kind of effect it would have to be wrong, but something to look at...

Also, I think I read that your LCD docs had something like "brightness" which you said was equivalent for the CORE's "contrast", but are you sure it's not supposed to map to CORE's luminance?

Maybe worth a double-check even if you think it's not the case :)

Marr

Marr

[Guest marr]

I was looking over the schematic pdfs last night and noticed a little warning about the transistor to the "LCD contrast" input..

it says something like "if you dont use the specified cap your BCE pins may be different..". Are you sure you have the right pins connected to the right places? I'm not sure what kind of effect it would have to be wrong, but something to look at...

Also, I think I read that your LCD docs had something like "brightness" which you said was equivalent for the CORE's "contrast", but are you sure it's not supposed to map to CORE's luminance?

Maybe worth a double-check even if you think it's not the case :)

Marr

Marr

[oberg]

Thanks for your suggestions, I'll take a look at them when I've gathered enough entusiasm. It's more fun building things that work...  ;)

...but perhaps I shouldn't be complaining, I burned my PICs with a working JDM-module on my first try, which seems to be a success worth remebering seeing the other posts here.

Regarding the brightness/constrast thing - I really don't know. Perhaps I've messed things up. All I know is that on the CORE module the pins are labeled:

VS, VD, V0, RS, RW, E, D0-D7

...and on my LCD (according to the datasheet):

VSS, VDD, VBT, RS, R/W, E, D0-D7

I've just assumed that the LCD's VBT (brightness adjustment) corresponds to V0 on the CORE since Luminance is supposed to go to the backlight LEDs.

I'll recheck for shorts and see if I can have misplaced my transistor (did so on the PSU circuit).

[oberg]

Thanks for your suggestions, I'll take a look at them when I've gathered enough entusiasm. It's more fun building things that work...  ;)

...but perhaps I shouldn't be complaining, I burned my PICs with a working JDM-module on my first try, which seems to be a success worth remebering seeing the other posts here.

Regarding the brightness/constrast thing - I really don't know. Perhaps I've messed things up. All I know is that on the CORE module the pins are labeled:

VS, VD, V0, RS, RW, E, D0-D7

...and on my LCD (according to the datasheet):

VSS, VDD, VBT, RS, R/W, E, D0-D7

I've just assumed that the LCD's VBT (brightness adjustment) corresponds to V0 on the CORE since Luminance is supposed to go to the backlight LEDs.

I'll recheck for shorts and see if I can have misplaced my transistor (did so on the PSU circuit).