These LEDs are very common. 5 minutes sourcing via Google brought up MANY suitable replacement from quality companies such as KingBright, ROHM, Vishay. All had immediate delivery on the white LEDs in sizes of 201, 402, 603, 804, 1206 in quantities of 200,000 to 1,000,000. These 3 companies produce the highest quality LEDs available on the open market and have zero lead time for delivery.
Seeing as these high quality LEDs are available NOW, Uniden must be sourcing cheap junk LEDs like what's already in the flagship scanners.
Really sounds like more "lip service" and attempts to buy even more time with excuses after excuses.
If you remove a LED on the x36HP, you will realize there is not proper heat sinking on the ground tab of the LED. A simple redesign of the circuit board to include a ground heat sink for each LED would most likely reduce, if not eliminate, the dimming displays even with the cheap LEDs.
Ha, I did not find any heat sinking behind the OEM LEDs!
Mine is an early model and one of the first 200 made.
ALL the LEDs in my 536 for the LCD and the Keypads are identical in all aspects.
Same voltage feeds them all but they are wired in series for each pair of two LEDs. The high side remains at 8 VDC to ground and they float the low side to dim or turn them off.
I did not bother looking at the two that illuminate the function knobs alert ring.
Like you, I also found several suitable replacements at Mouser alone and actually ordered some of the brightest white ones (guessing at the mcd output and color temp) made by OSRAM but I screwed up.
I was in a hurry to make their 8 PM cutoff time for same day shipping and I did not pay attention to the thickness of the models I ended up buying.
They fit length and width wise but not height! The bad thing is I actually had two KingBright models in my cart that would have fit fine but I swapped them for the Osram's as the Osram's had a slightly higher max voltage rating. My 536 measured a max voltage at each LED just under 2.9VDC and the OSRAM LEDs I bought had a rating of 3.2VDC.
I ended up buying two different models made by Osram that were nearly twice as tall as the ones Uniden used so no fit behind the light spreader for the numeric keypad. They may fit for the LCD backlights though as that light spreader appeared to be taller where the LEDs sit.
I still tested the two I bought in free air and current consumption was fine plus they emitted almost zero heat (after burning on high for over an hour) but they had the same or greater light output compared to when my 536 first came out of its box.
A color temp of 5600K was noticeably yellower (still almost undetectable) at the low setting only but would have still been plenty white enough. The other Osram had a color temp of 6500K
They put out 2240 mcd of light if ran at their recommended upper voltage of 3.2VDC, that would have been brighter than Unidens LEDs. My 536 only puts out just under 2.9VDC on high though so I was not running the OSRAM at full brightness but it was still at least as bright or maybe even a tad brighter than when my 536 was new out of the box.
All my LEDs in my early production 536 are identical. Same voltage, brightness, size and color. No difference at all like Voyager found. Maybe they changed something in different production runs.
All my LEDs are also wired in series of two LEDs per series circuit.
With that type of circuit, if an LED failed shorted, it would take out the other instantly when its voltage doubled. If one failed open (or is removed), it would just cause power loss to the other in that circuit.
I also found the reason I'd seen ALL my LEDs go dim for about a week until I opened it up and bumped something before I could find the cause a few months ago.
It was the 35 conductor ribbon cable that connects the front panel board to the main board. I hit it again this time while figuring out the new LED problem and I saw all the LEDs dim slightly or flicker as I bumped around on the ribbon cable.
So I ordered some Molex cables of 50mm length and .050 mm spacing for the contacts. I also stayed with the same connector end thickness of .027.
The only problem was Mouser does not sell a 35 conductor cable. They sell 40 though so I bought that and just trimmed 5 conductors off each end of the new cable.
The new cable was also about 1/2 inch shorter than the one Uniden used. Still plenty long enough with lots of slack so no stress placed on the sockets or the new cable. I did not want to chance using a longer cable not knowing what kinds of signals flow through the cable.
I did try reseating the original cable first but that did not last long at all before they all went dim again. Basically a matter of minutes before they started growing dim.
I must say that replacing that cable only, restored my backlighting to the same level they had when I first turned the thing on!
I don't know if the OEM cable just has cheap tinned ends that compressed or if the sockets use contacts that don't keep their form after time but something sure caused my ribbon cable to no longer make a good connection for at least the 8VDC signal that powers the LED circuits.
Of course if you only have a few LEDs that are dim, the cable is likely not the problem but if ALL LEDs are dim, I'd take a look at the ribbon cable.
The sockets appear to be decent quality and actually have a nice retention mechanism also but who knows the quality of the actual metal contacts inside those sockets.
Swapping the ribbon cable on mine with one of the same thickness as measured at the contact or tinned ends of the original cable sure made a difference in my 536 lighting.
Who knows who made the sockets or the ribbon cable Uniden used but one or the other may be poor quality or I was just unlucky.
I know they have had problems with other models in the past but most of that was caused be heating and cooling causing the ribbon cable to walk themselves out of the sockets. That was not the problem with my 536.
I also lost an LED behind the keypad and that was not caused by a bad ribbon cable so they may have two things going on.
I think most posts on this subject have just some failed LEDs so I may have just been unlucky and got one with a bad cable.
When I first found all LEDs dim though, I knew it was not the LEDs at that time and it had to be something more common to the entire circuit.
If one does not have the skill and proper rework tools, don't even think about attempting an LED replacement. Take up Unidens offer of replacing them if they ever get that program going.
I have the tools and skills needed but I'm not sure my old eyes are up to the task of swapping them all. I'll probably just replace the four behind the numeric keypad and take my chances that the ones behind the LCD will not fail! That poorly connected ribbon cable probably added some life as well plus I do run it on low or medium and rarely on high when I'm actually using it. Otherwise it is used for logging with the backlights off.
With the new ribbon cable, low is plenty bright enough again even with bright room lighting.
Of course replacing my ribbon cable did nothing for the LED that did fail the other day behind the numeric keys. I did not expect it to help either as I knew that one was an LED failure.