4PM Issue / No LCD

I finished soldering up my 4PM, connected the filter board to the control board and fired it up without the LCD attached. According to the build/test instructions, I was able to toggle around with the buttons to verify that the LEDs were cycling properly. I then soldered on the LCD display and tried adjusting the trimpot, but was unable to get a display to show up. The buttons would not cycle at this point and the 4PM seemed to be locked up. I have attached a photo of it powered on with the LEDs that are lit up. The backlight of the LCD does appear to be on.

MCU pic

Finished Midipal :slight_smile: Booted up first time no issues!

The MCU wasn’t too bad (I need glasses lol), I found that putting a small drop of solder on the chisel tip worked best and flux penning all of the pads before dragging the small solder drop on the leads. I will take some pics when I get off work.

Oh! and Frank suggested that I dremel out the LCD or cut the pins between the LCD and the board. I actually found a really cool solder trick to remove components (potentially save them) and in this case the orange LCD. Basically I applied a large pool of solder to the top part of the LCD pads, and essentially bridging all of the pins into one large line of solder. By doing this, I was able to heat all of the pads at the same time and was able to lift the LCD off of the header without destroying it. I then used solder wick to wick up all of the solder on the orange LCD! :slight_smile:

How did you do with the MCU? Post a pic!

My wife said the other LCD was orange. I’m color blind, so those colors just run together anyway. Anywho, building the 4pm was a great experience and a very challenging one at that. Somehow I managed to not destroy the orange LCD, but at this point, I have no idea if it works. Now I’m working on my Midipal and it has its own set of challenges. After trying various solder tips, I find the chisel tip to be excellent for just about all soldering working from SMD to thru-hole. Also, everything flows better with the flux pen when doing SMD stuff. I use Kester brand for everything. Kester makes some high quality soldering materials. I am about half way thru the Midipal project and hope everything fires up the first time. :slight_smile:

aww, I kinda liked the yellow LCD :stuck_out_tongue:

Happy Shruthi! Thanks for the replacement LCD Olivier!

Cut the pins BETWEEN the LCD and the PCB and desolder one by one. Heat, push/pull (to your like) out the Pin and THEN remove the Rest of the solder either with Wick or by pushing thru a needle from a Syringe (the solder won’t stick on the Stainless Steel Needle. Never try to remove a MultiPin Item if you can make it a single Pin Problem just by sacrificing a 0,05€ Part)

I don’t think you can remove the LCD from the header while it’s attached to the Shruthi. Not without a suction/reworking rig.

Best you can hope for is to carefully dremel between them, likely sacrifice the LCD, and hope you don’t gouge or screw up any traces on the Shruthi board from all the hell you’re going to put it through.

In all likelihood, unless you’re really great at this or really lucky, you will lose a couple of pads on the control board and you’ll have to solder jumpers back to the ATMega. It’s not the end of the world, but it’s a helluva lot of shit to go through when you have a functioning display.

Next time socket the LCD. I’m doing this from now on no matter what. It’s way cheaper than buying a desoldering station.

Well, couldn’t you solderwick the solder from the pins on the LCD side? IE removing the LCD, not the LCD+16pin header?
This way the only thing that would run the risk of being damaged would be the LCD pads, not the shruthi-1 PCB . .
Having successfully replaced a LCD once, the only thing i remember is that it’s a major PITA :confused:

I was thinking the same thing. Desoldering the LCD side does seem like a viable option.

If you aren’t bothered about the LCD then use the dremel cutting disk to cut slots into the pads on the outside edge of the LCD board. Once the solder had been wicked away you can pull it away from the pins easier?

Brute force, but possibly easier?

you already have a special price, this will bid worth a fortune some day like the Blue Marituis

Hmm. Okay I stand corrected. I thought the b/w 4PM display was an OLED. Nice looking LCD then.

What are the odds that I got the random LCD with my kit. Maybe I should get a special prize. :slight_smile:

It’s not an OLED (there’s a glow of the orange/yellow backlight LED on the right hand side), but looks fine.

I swapped the control board on my 4PM for one with an OLED and yellow LEDs instead of white. Looks like yellow snow lol.

crank up the resonance!

turning up the resonance will activate the LEDs?