LED colors

Phillip Porch, MD

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Oct 8, 2025, 4:32:39 PM10/8/25

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I noticed when testing the LEDs that some were a pretty bright white and others seemed less intense and had a yellowish hue to them. I don't think it looks bad, kind of like you had some incandescent lights that were older and not quite as bright. It looks like there might have been 2 lots of LEDs in my kit. I wondered if anyone else had noticed this?

Mike Arrington

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Oct 8, 2025, 5:10:13 PM10/8/25

to Phillip Porch, MD, [PiDP-1]

I had the same problem. CEDS is aware of the problem.

I purchased the rack version and the LEDs that came with the rack kit were yellow. The console part of the kit had a mix of both white and yellow. I was able to use the rack's yellow LEDs to substitute for the console's white LEDs. There were enough white LEDs to make the I/O panel one color.

On Wed, Oct 8, 2025 at 3:32 PM Phillip Porch, MD <ppp...@gmail.com> wrote:

I noticed when testing the LEDs that some were a pretty bright white and others seemed less intense and had a yellowish hue to them. I don't think it looks bad, kind of like you had some incandescent lights that were older and not quite as bright. It looks like there might have been 2 lots of LEDs in my kit. I wondered if anyone else had noticed this?

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Phillip Porch, MD

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Oct 8, 2025, 5:17:15 PM10/8/25

to Mike Arrington, [PiDP-1]

Thank you for confirming this. You were smart to sort them into colors. I was just checking that they worked and didn’t think about separating them.

Oscar Vermeulen

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Oct 8, 2025, 8:22:45 PM10/8/25

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Philip,

Can we fix this for you? Send some extra LEDS and a solder sucker to replace the wrong-mix LEDs? Or a new IO panel, that might be quicker than replace the LEDS on that one. For the main PCB, just changing some LEDs will be quicker.

Yes. We are now testing every single LED that goes into a kit, until we are sure we have a batch of the LEDs delivered from the manufacturer themselves. That is no fun, I can tell you...

It is the reason no new kits went out for a week, we start tomorrow again.

But I got to make you good on this :-(

Kind regards,

Oscar.

Kristen R.

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Oct 8, 2025, 8:35:06 PM10/8/25

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I haven't noticed this LED color issue, but wasn't looking for it. Is there an easy way to turn on all LEDs at the same time?

Thanks,
Kristen

Oscar Vermeulen

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Oct 9, 2025, 8:21:15 PM10/9/25

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Kristen,

On Thursday, October 9, 2025 at 2:35:06 AM UTC+2 k...@elitemail.org wrote:

I haven't noticed this LED color issue, but wasn't looking for it. Is there an easy way to turn on all LEDs at the same time?

It was a one-off fluke - the manufacturer put two tones of white in one bag of 1,000. I think we've chased up the expected 7 kits that were affected. But if you have one, let us know. This group in general is far too nice in accepting things like this.

Another problem we're currently grappling with: it seems about 0.5% of the LEDs are not working. Or maybe they too are the wrong colour, black?

So now we test every single LED before it goes in a kit. It is not fun, and is why we're slow shipping out kits. Well, we're running out of PCBs soon too, as JLCPCB delayed a 2-week order into a... 8 week turnaround, by now?

I'm sure someone will say this LED problem can be solved by buying through Mouser. Yes. If we want to add $50 to the cost of each kit. We'll just keep checking all LEDs until we receive the parts for a little LED tester, that will then be part of the kit.

Because not many things are more annoying than soldering up a PiDP-1, discovering one LED is dead, bug hunting why that is (the rule is 'least likely is a dead part', so go check all your soldering etc), and then having to take the machine apart.

So, a little LED tester will be part of the kit as soon as the parts (we need a USB cable for this) arrive. Till then, I plan not to see Jose in person because he's not thrilled by this. But agrees it is necessary.

Kind regards,

Oscar.

Adam Thornton

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Oct 10, 2025, 8:45:13 AM10/10/25

to Oscar Vermeulen, [PiDP-1]

Also I know the warnings are very scary on "don't heat a switch for more than 7 seconds" but I have not broken one yet, even when desoldering a very recalcitrant one.

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Unibus

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Oct 10, 2025, 8:45:19 AM10/10/25

to Oscar Vermeulen, [PiDP-1]

Hi,

Hopefully your LED tester has a reference LED wired in series so that you can compare colour, intensity and presentation with the LEDs under test.

Regards,

Garry

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Malcolm Ray

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Oct 10, 2025, 8:45:23 AM10/10/25

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Well, I had one dead LED out of 194 (0.5%), and I'm sure it wasn't one of those legendary black LEDs, because it tested as open circuit.

All the other LEDs are the same colour and approximate brightness.

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Oscar Vermeulen

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Oct 10, 2025, 8:59:19 AM10/10/25

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On Friday, October 10, 2025 at 2:45:19 PM UTC+2 uni...@gmail.com wrote:

Hopefully your LED tester has a reference LED wired in series so that you can compare colour, intensity and presentation with the LEDs under test.

That won't be necessary, the problem was with LEDs of two different colors. I think Warm White and Cold White. The wholesaler gave us one bag with a mix of them!

The real problem is 'black LEDs' versus 'warm white LEDs', so a little tester for that would suffice. It is just tremendously annoying to find your board with a LED that does not work. Because, is it a soldering problem? Or a dead LED? Then you have to open up the panel and replace it. That is too annoying.

So for now we test all LEDs in each kit to eliminate this risk. But that's not sustainable... then the LED tester will be the line of defence.

Kind regards,

Oscar.

Unibus

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Oct 10, 2025, 11:45:41 PM10/10/25

to Oscar Vermeulen, [PiDP-1]

Hi,

The attached photograph illustrates LED differences. This is a photograph taken of some LEDs from my PiDP-10 with its display frozen. The colour balance on the camera was wrong as these were yellow LEDS. I was holding the camera for a very long exposure so it is a blurred image. The top right LED has a bright spot. If I used a tripod then the bright spot would be a circular, very well defined, very bright spot. The bottom left LED is significantly brighter than the other LEDS. If you are trying to match LEDs.

I would consider all the LEDs with a bright spot to be defective. I'm not going to do anything about them. I wouldn't have even raised the issue except it illustrates the reason for my suggestion.

Regards,

Garry Page

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IMGP6971-1.JPG

Charles Ess

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Apr 8, 2026, 6:25:40 AM (2 days ago) Apr 8

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I was just sorting through the leftovers from my #248 rack build - lots of spare parts, along with the switch/LED tester mentioned here. Very nice! I wish I'd seen it before using my breadboard tester - and perhaps I missed it somehow, but I didn't see a reference to or description for how to solder / wire it up in the building instructions? Not hard to figure out from the print on the PCB - but if its missing from the parts list and building instructions, would be good to add at some point.

Many thanks for it in any event. Just have to order another kit, I guess, in order to make good use of it ... ;-)

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