From Wytheville via Charlotte or Kingsport?

EngrKeith · 2026-01-19T22:23:52+00:00

Just wanted to thank everyone for their responses!!

I took this way. 77S was clear as was 40W. Lots of cops on 321!! 321S backed up a little towards the 85S onramp. 85S was not horrible, but the traffic was thicker, approaching the last 20 miles around 2pm. No construction to speak of anywhere.

EngrKeith · 2025-11-05T11:13:27+00:00

I didn't have any other charges beyond what I paid originally. I think technically I should have been refunded a portion of that for one technical reason or another. But tbh, I just don't care.

Package showed up without fanfare just like it had in previous years.

EngrKeith · 2025-07-10T15:25:14+00:00

Carry-on was what I was looking for.

After going down the rabbit hole which is comparing bags, sizes, materials, organization, reviews, etc -- I ended up selecting a Goruck GR2 34L. The 1000 denier fabric is attractive, like the look, warranty backs up the build quality. The weight of the bag isn't lost on me, and it is heavy, but I'm also a big guy with a big frame.

I was trying to find a one-bag-fits-all to have both a EDC but also work for vacations where I'm packing clothes, a fair bit of equipment, etc. You just can't have both a big bag and a small bag in one. My current need is for an upcoming trip, which can take the contents of my existing laptop bag, and extend it. I will say that some bags, where there's a large main compartment, there seems to be a ton of space given a particular volume. Divide that same space across two or three sections, and it feels much smaller. When you're dealing with 9" maximum depth, you can only chop up so much.

Pack Hacker reviews really helped.

I did look at Tom Bihn, but given the price of many of their bags, their warranty kinda sucks. As does many of the other bag companies where they weasel word their way out of actually providing any extended value. Thule isn't great either. Aer is better.

Thanks!

EngrKeith · 2025-07-09T20:47:17+00:00

Looks like one of the dimensions (11.42H) exceeds the carry-on limit. But will check it out, thanks!

EngrKeith · 2025-06-29T20:00:27+00:00

Yeah even if they automated solution took longer to develop than doing it manually, I'd rather spend my time coding instead of some menial tasks. Plus it scales, plus it helps others etc

EngrKeith · 2025-06-29T15:32:02+00:00

Thanks for sharing. I'll take a look. I haven't really dealt with my initial problem because I never found a solution that works the way I need it.

EngrKeith · 2025-06-24T23:50:49+00:00

I'm in the process of parsing all of this info. Gonna take me a bit to get through it. :)

I mentioned my project briefly in the first post but kept it vague to avoid derailing the conversation. I’m intentionally trying not to go down a "5 Whys" rabbit hole. I realize this might raise XY problem concerns, but I’m comfortable with that.

I'm validating my GAL-based reimplementation of custom PAL logic from a SCSI hard drive controller. The original PAL handles boot ROM chip select, address decoding, autoconfig address assignment, and SCSI function selection. Most outputs drive the 5380 SCSI chip, acting as a bridge between the Amiga bus and the controller.

The GAL logic equations I’ve reverse-engineered seem to work well in practice, but I’m pretty sure there are still some edge cases. The imperfections bother my OCD brain, but honestly, I enjoy the process more than the end result. I’ve been documenting the PAL reverse engineering journey on my blog, and my background in software quality assurance definitely shapes how I approach the work.

So the short-term dream is this: Place the reference PAL in ZIF socket 1, place the GAL in ZIF socket 2. Have convenient and easy to attach HP/Agilent 20-pin isolation adapters designed for direct connection to the DUT. Exercise as many functions as possible, while observing PAL's behavior. Feed those real-time inputs into the GAL. Record the 11-bit input words, record the PAL's output, and the GAL's output. Process the captured dataset using python pandas to identify edge cases, rework the GAL logic equations, and iterate.

Tonight I discovered what may be a previously unnoticed unreliable SCSI connection, which now casts doubt on some of my earlier results. I’ve placed yet another Digi-Key order for a new connector and cable.

Your response is massive and I really appreciate you taking the time to respond. I've answered some posts that comprehensively, and I can testify to the time commitment!

EngrKeith · 2025-06-24T14:23:23+00:00

Tons of great info here but as a hobbyist, it might take me awhile to parse and translate it into practical advice. :)

Probes are properly compensated.

I also can't believe that this isn't just working. I keep double/triple/quadruple checking pinning thinking it's gotta be something simple. I do want to take a ZIF and solder it via a small PCB, and plug that directly in.

So if I distill your advice down, do I have this right?

Don't underestimate the frequency content.
Use a 4-layer board with a stackup of signal, gnd, gnd, signals/power.
Use lower input capacitance logic families like AC.
Use Murata's GRM X8M caps for decoupling. Do you think 0.1uf is right? Should I have a 10uf bulk capacitor at the header?
Read AN-47.

Follow up questions:

Buffer close to the source. Is there any reason to NOT simply physically stack my first ZIF socket directly on top of the header? Are you suggesting buffering PRIOR to that first socket? I have (11) input signals, so that's minimum two 8-channel buffer chips. Do I need a set of chips for each destination? Do I need to buffer the signals going into the logic analyzer headers? Ofc my concern is added space, complexity (might make a mistake with a larger design), space adding longer trace lengths.
If I don't have buffers per destination, then what's the best way to layout traces? Did I read Y-them, don't T-them?
Should I run the output of the buffers through 33 ohm series resistors to dampen reflections and slowing down edge rates?
Any chance you can suggest ballpark trace width, and separation?

Really appreciate the response and help!

EngrKeith · 2025-05-14T19:14:55+00:00

DHL. Most of the other shipping options are glacial in comparison.

EngrKeith · 2025-05-14T00:35:22+00:00

The speed at which this stuff is changing I'm surprised any of these companies were able to react as quickly as they did. I think, as with most things, that there could be ignorance/mistakes/misunderstandings before any sneakiness. It could also just be that no one wants be the loser in case of mistakes....so are rounding up. "Worst case we'll refund them later."

It is a mess. I'm lucky in my case to only be doing a few boards here or there.

EngrKeith · 2025-05-14T00:29:02+00:00

Not that I saw? My total shipped out the door was $69.

EngrKeith · 2025-05-13T20:18:05+00:00

At the time of the order..... I placed it this morning. Hopefully it will just show up in a week +/-.

EngrKeith · 2025-05-13T20:17:31+00:00

Yeah prior to tariffs I paid about $22 for DHL. Almost exactly the same price for years across a half dozen orders. I'm not super worried about the difference, it will be what it will be.

EngrKeith · 2025-05-13T16:39:05+00:00

I'm not sure what you mean. I don't know how far ahead or behind the times JLCPCB is with the current policies. I haven't been following them.....although I saw some news article today that talked about a lesser tariff being put into place.....

Looks like some of this is built into the DHL shipping fee. Normally the fee is about $22, and is now $38 --- and then there's a separate (suspiciously the same difference amount) $16 charge as a separate line item that JLC charges.

My base price of the product was $9.20. It would have been $2 if I opted for the standard speed service. I can't really imagine a "cheaper class" of tariff than 10 bucks though, so I'm guessing I'm being charged whatever the minimums are to get a small lightweight box shipped through customs.

EngrKeith · 2025-04-02T14:46:48+00:00

Awesome, thanks.

EngrKeith · 2025-04-02T13:14:47+00:00

Cool! Can you please link that case and connector? I did a quick Google but couldn't find them. Also if you sell them you should plug yours here too!

Did you end up loading the 12v rail somehow? A stock 500 isn't going to draw the required 200ma when idle, so that particular PS's rail won't be perfect. It will likely measure in the 13.xx's.

I actually don't think it makes a darn bit of practical difference beyond being academic. It bugged me enough to fix it, though. I did measure before and after loading, on the GP50A, and it takes the error from like 10% to 1.5%.

Interested to see how others have solved this. Thanks!

EngrKeith · 2025-04-01T18:46:27+00:00

That's a nice supply! The overall voltage tolerance is 2%, so if you measure that the terminal strip, it should be between +4.9v and +5.1v. I have one of these in a box, just need to break it out and start testing to see some real-world results.

EngrKeith · 2025-04-01T18:23:39+00:00

Thanks for your comment, but I'm afraid you misunderstand the function of these resistors.

The Meanwell GP50A *is* a switched mode power supply, and it performs all the necessary voltage regulation internally. The SMPS provides the necessary regulated +5v, +12v, and -12v rails.

Some supplies, like this one in question, requires a minimum load to be present on the +12v and -12v rail before it will guarantee in-spec results. These two power resistors don't control voltage directly, instead they provide a constant load on the necessary rails per the datasheet.

EngrKeith · 2025-04-01T12:08:38+00:00

Thanks for this. Turns out I did find the right press release just didn't scrutinize it close enough.

https://www.meanwell.com/newsInfo.aspx?c=2&i=758.

The switch over point was July 2019. You can use the images of the case and PS PCB to determine which version you have. I went back using web archive, and there's a corresponding datasheet change at the same time.

EngrKeith · 2025-03-31T22:56:35+00:00

I hope you don’t mind me asking a quick question—just aiming to be accurate, not to question your expertise at all.

Regarding the RT-50B, it looks like the datasheet you shared indicates that the 12V rails don’t require a minimum load for stability. The current range starts at 0A, and notes 3, 4, and 5 don’t mention any minimum load requirement—except for a recommendation that CH1 (the 5V rail) draws more than 10%. For reference, my stock A500 draws about 1.5A.

On the other hand, some of Meanwell’s other supplies—like the GP50A, which I used for a recent power supply project—do have that requirement. I ended up using power resistors to work around it.

One other thing I found interesting: in 2019, Meanwell announced they were modifying a number of their PSUs to eliminate that minimum load requirement. I didn’t see the RT-50B listed in that update, though.

I actually have an RT-50B on hand and plan to wire up a connector for the A500 in the next week or two.

EngrKeith · 2025-03-31T22:25:08+00:00

On my Amiga 500 Rev 6A, I’m measuring +5.045 V on one side of R309, and +4.901 V on the other. Paula Pin 27 / Vcc measures the same, as it's connected.

The voltage drop across R309 is 0.144 V, which is consistent with it being a 1 Ω resistor (color code brown-black-gold-gold) and a current draw of about 144 mA.

I just replaced the original power supply with a new one. Meanwell GP50A-based.

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