Problems with Parallel Display from eBay...

dan0h · Post by **dan0h** » January 21st, 2006, 9:07 pm

Firstly let me say hello forum goers and LCD peeople, I know the topic sounds ominous!

As an LCD n00b I bought a pair of new 20x4 displays from the eBay store http://stores.ebay.co.uk/HNQH-LCD whom I saw came on the recommendation of another user of this forum (cant recall the name though).

I have one of the displays wired up to the parallel port, and have checked the wiring over three times, but the display won't go any further than past its initialization screen, I have the top and third lines of the display showing boxes and the second and forth blank - which I am assuming is its initialization.

If I use the CrystalFontz parallel testing/debugging software the display appears to move through a number of characters and initialize, but LCDSmartie just wont work with it, no combination of ECP/EPP/SPP and Timing multiplier seems to work.

The display part numbers are:

UC204A-YP-RB-N (non-Illumination, this is the one I am using right now.)

And a...

UC204A-YP-FB-N-LB-YG (Illuminated, as yet untried as I wanted to test with the non-illuminated one first).

Both the LCDs are branded "Unitech" on the back. Does anyone have any experience with these displays (maybe the member that posted the eBay store link?)... Any help very much appreciated. Though I must admit I am now tempted to try the illuminated one also just incase there is a compatibility issue...

Thank you!

jonny · Post by **jonny** » January 21st, 2006, 9:56 pm

check your port numbers in smartie and match them to the configuration for the crystalfontz testing software. if the lcd works in another program, than it is not the wiring that is the problem.

dan0h · Post by **dan0h** » January 21st, 2006, 10:04 pm

Well the crystalfonts kind of works, I am now also on the other display with illumination - and the results are so far identical. I am guessing that these displays are not quite HD44780 compatible, they were sold as such though.

The port settings between the two App's match up, but while Crystalfonts does do something with the display (ie. Random characters moving left to right and then stopping) I still cannot get even the Crystalfonts test software to display any user text... Hmmm...

Thank you for the post though Jonny, I should have been a little clearler in my original post!

Can anyone confirm they have had these displays working!?

dan0h · Post by **dan0h** » January 21st, 2006, 10:58 pm

Found the problem!

Two broken wires making momentary contact, they seemed to keep the display initializing over and over...!

Post by **limbo** » January 21st, 2006, 11:54 pm

Sorry I missed your post...
I'm using Unitech LCD's without any problem.

If you getting nothing but the block you have to check wires and program configuration.

These sceens are fully compatible with LCD Smartie. Thats for sure!

dan0h · Post by **dan0h** » January 22nd, 2006, 8:26 pm

limbo - thats the name I saw previously!! Thank you for your reply. There was a broken wire in the cable I was using (old printer cable), but now I have verified it all works I am ordering an enclosure and some stripboard to make a nicer job of it, I am thinking of pulling the +5 for the screen and Backlight from a USB lead, anyone have any experiences with this? I mean, does it provide enough power? I would have guessed yes, but it never hurts to ask

Post by **limbo** » January 23rd, 2006, 6:37 am

Usb Provides quite enough power....
Penjuin has builded and usb-powered lcd...

I suggest to use it in line with a fuse just in case of any short circuit!