feipoa wrote on 2022-12-11, 21:44:

Is 1 M-ohm input impedance not sufficient for these measurements?

yes, check bandwidth of your probe in 1x mode.

feipoa wrote on 2022-12-11, 21:44:

This is the interposer GND I've been using for the last little while and with these tests. It is as short as I could make it. Clipping two probe GNDs directly to the header was causing shorts with the adjacent 5V pin, so I had to use a connector:

watch video linked above

I watched the link. Thanks.

I don't think I have an extra BNC cable I want to hack up like that poster did. My probes have a 15 cm ground lead. I'm not sure how to shorten that without destroying the lead. The distance from the ground lead attachment to the probe tip is already 7 cm, so the shortest possible GND cable for my existing probe would be 7 cm. I don't have an internal GND as part of the probe tip like that Tecktronics unit shown in the video.

This is how I've connected GND for all the tests - directly to the GND header on the interposer. Should I not be doing this? I was pretty sure I was supposed to connect VCC and GND to the closest point of the VRM. With the LP regulator, I don't have the lead sticking down like I used with the MIC regulator. For LP, I've been using:

Previously, I had a slightly longer connector on the pin header, perhaps 3-4 cm longer than shown above. It looks like:

I did not see any change when I switched to the shorter stub.

I also do not see any change in the waveform when poking around the GND with my finger, like shown in that video.

Probe bandwidth... by the markings on the probe, PP510 100 MHz.

Aside from hacking up probe or a BNC cable, is there anything you recommend I change in the setup?

PP510 Bandwidth: 6 MHz (X1)

pull on the tip, its removable, dig in the box scope came with and find rest of accessories, find the spring and put it on

Anyone with photochop able to super inpose these I’m not in front of computer for a few days and feiopa and I are trying to figure out how much closer the pin header is to the cpu.

Scale and center images so that the four cpu pins line up ontop of one another

Or… if someone wants to open up the previous version (one feiopa has) and the latest place save from a couple posts back and measure. That would work also 😀

What's the 100 MHz for then? The 1x probe and the 10x probe are the same, just a switch on the housing. x1 = 6 MHz and x10 = 100 MHz? More likely seems x1 = 10 Mhz and x10 = 100 Mhz, no?

The box the scope came in? lol. That was thrown out 12 years ago. I looked in the package I kept the probes in, but there's no spring or alternate assembly. Looking thru the PDF manual, I don't see any mention of a spring in the accessories section.

By way of comparison, here's the Improve-It plus Gainbery VRM at w/x10 probe:

Edit: @Sphere, there is no rush. Just check it when you are home.

feipoa wrote on 2022-12-12, 02:54:

What's the 100 MHz for then? The 1x probe and the 10x probe are the same, just a switch on the housing. x1 = 6 MHz and x10 = 100 MHz? More likely seems x1 = 10 Mhz and x10 = 100 Mhz, no?

no 😀
https://res.cloudinary.com/iwh/image/upload/q … es_brochure.pdf
absolute probe basics https://www.youtube.com/watch?v=rzo4Ntxqu1E

feipoa wrote on 2022-12-12, 02:54:

The box the scope came in? 🤣. That was thrown out 12 years ago. I looked in the package I kept the probes in, but there's no spring or alternate assembly. Looking thru the PDF manual, I don't see any mention of a spring in the accessories section.

its visible in the linked brochure, but you can make one yourself https://www.youtube.com/watch?v=-4q8geE5ef8

feipoa wrote on 2022-12-12, 02:54:

By way of comparison, here's the Improve-It plus Gainbery VRM at w/x10 probe:
Improve-IT_plus_Gainbery_VRM_setup.JPG
Improve-IT_plus_Gainbery_VRM_scope.JPG

at this point I wouldnt worry to much about previous measurements 😀
try this setup: find/make a spring or solder a diy spring probe receptacle, set 10x, compensate probe, set scope to FFT/Hanning window mode
fft basics https://www.youtube.com/watch?v=EqRvUyPhbu8

Hey rasz_pl, can you generate the gerbers for this and send to feiopa. download/file.php?id=152383

I’m away from keyboard for a couple days. I suggested feiopa just order it since it is $2.50 🤣 before we risk missing the sale.

Last I looked at it it looked pretty good. I’ll continue tweaking it but it seems the significant stuff is done. The last hour I spent on it has been basically tweaking silk screen and silly stuff 🤣. By the time he gets the $2.50 order I should know if there were any significant errors haha. Seems like a gamble worth taking.

You could look it over if you like, lmk if you see anything.

Plenty of time. See screenshot.

No matter what, I think both fan header pins should be on the outside of the overhang, this way if they receive a unit with offset heatsink, like I have 1 in 3, it won't interfere with the fan header. And the other header, for IBM systems - maybe 1% will use this, so put it inside for increased usability.

I uploaded your latest zip, but it auto-detects as 2-layer and even if I select 6-layer, it shows $2.50. This value is in disagreement with the advertisement of $20. Perhaps something is up again.

rasz_pl wrote on 2022-12-12, 04:01:

no :) https://res.cloudinary.com/iwh/image/upload/q … es_brochure.pdf absolute probe basics https://www.youtube.com/watch?v=rzo4 […]
Show full quote

feipoa wrote on 2022-12-12, 02:54:

What's the 100 MHz for then? The 1x probe and the 10x probe are the same, just a switch on the housing. x1 = 6 MHz and x10 = 100 MHz? More likely seems x1 = 10 Mhz and x10 = 100 Mhz, no?

no :)
https://res.cloudinary.com/iwh/image/upload/q … es_brochure.pdf
absolute probe basics https://www.youtube.com/watch?v=rzo4Ntxqu1E

feipoa wrote on 2022-12-12, 02:54:

The box the scope came in? lol. That was thrown out 12 years ago. I looked in the package I kept the probes in, but there's no spring or alternate assembly. Looking thru the PDF manual, I don't see any mention of a spring in the accessories section.

its visible in the linked brochure, but you can make one yourself https://www.youtube.com/watch?v=-4q8geE5ef8

feipoa wrote on 2022-12-12, 02:54:

By way of comparison, here's the Improve-It plus Gainbery VRM at w/x10 probe:
Improve-IT_plus_Gainbery_VRM_setup.JPG
Improve-IT_plus_Gainbery_VRM_scope.JPG

at this point I wouldnt worry to much about previous measurements :)
try this setup: find/make a spring or solder a diy spring probe receptacle, set 10x, compensate probe, set scope to FFT/Hanning window mode
fft basics https://www.youtube.com/watch?v=EqRvUyPhbu8

I remember this guy, very enthusiastic. I'll have to watch after everyone is asleep and yelling no longer fills the air with bitter melody.

I did some digging through various drawers and found what sort of looks like the presentation in that catalogue, however I don't know what these do and there is was no spring in the bag.

EDIT: Ok, that eevblog video explained a lot in just 3 minutes. I had never taken the clips off the probe tips before. I'll see if I can make a spring thing for the probe tip's GND.

EDIT2: I'm going to try to make the spring ground connector. My unit must not have come with one since it wasn't in the bag.

rasz_pl wrote on 2022-12-12, 04:01:

try this setup: find/make a spring or solder a diy spring probe receptacle, set 10x, compensate probe, set scope to FFT/Hanning window mode

Is there some cheap already assembled probe available for purchase which will meet the requirements?
EDIT: Never mind this comment. Now that the house is asleep, my brain can function. I'm going to make the coil out of 22 AWG.

feipoa wrote on 2022-12-12, 04:50:

Plenty of time. See screenshot. […]
Show full quote

Plenty of time. See screenshot.

No matter what, I think both fan header pins should be on the outside of the overhang, this way if they receive a unit with offset heatsink, like I have 1 in 3, it won't interfere with the fan header. And the other header, for IBM systems - maybe 1% will use this, so put it inside for increased usability.

I uploaded your latest zip, but it auto-detects as 2-layer and even if I select 6-layer, it shows $2.50. This value is in disagreement with the advertisement of $20. Perhaps something is up again.
PCB_Sale.png

There are no gerbers in the latest zip. Were you able to generate them?

Apparently they have high and standard precision pcbs now

Sphere478 wrote on 2022-12-12, 05:10:

feipoa wrote on 2022-12-12, 04:50:

Plenty of time. See screenshot. […]
Show full quote

Plenty of time. See screenshot.

No matter what, I think both fan header pins should be on the outside of the overhang, this way if they receive a unit with offset heatsink, like I have 1 in 3, it won't interfere with the fan header. And the other header, for IBM systems - maybe 1% will use this, so put it inside for increased usability.

I uploaded your latest zip, but it auto-detects as 2-layer and even if I select 6-layer, it shows $2.50. This value is in disagreement with the advertisement of $20. Perhaps something is up again.
PCB_Sale.png

There are no gerbers in the latest zip. Were you able to generate them?

Apparently they have high and standard precision pcbs now

That explains it. I didn't even look in the zip, just clicked DOWNLOAD, then UPLOAD. At any rate, we have plenty of time.

rasz_pl, I have done as you suggested by making a low inductance ground tip for my oscilloscope probe. The probe tip's ground connection has a 4.78 mm diameter. I used a drill bit of 4.32 mm diameter to create the coil with solid 22 AWG. 6 full wraps. I spaced the GND lead out so that the distance from the tip to GND tip equalled the distance from the LT1528 OUT to GND.

First, I took a measurement with the original probe configuration (yellow) plotted against the low inductance ground model (blue). Then I took another shot without CH1 (yellow) connected all together.

It looks as if the low frequency waveform is still present and the Vpp is about the same as the noisier probe's connection.

EDIT: I'm continuing to watch that eevblog guy's video on the probes and at around 6:40 it seems like he says to use x1 mode for measuring low voltages, which I'm assuming that's what we're doing if looking at 50 mV swings. Am I mistaken?

@feiopa
The feature pin header appeared to meet the same clearance on my end that you said is okay for the trim pot and regulator. I am asking to be extra sure. I fear though you don’t have the answer as you don’t have the measurement from the file. I can’t get that to you at the moment. Wait, or see if rasz can help. But it looked okay on my end. You have said that the wire connector that slips over the pins is no bigger than the abs pad. If so, should all be good. But I may none the less be able to move the pins out without making it bigger again, I have an idea. Clearance is a good thing.

You want the fan header far from the heatsink. And the other two ibm ones farther in Let me look to see if this makes sense. I suspect that it won’t because the traces will cut down the 5v plane to the outer pins, unless I get creative (again) Ideally, I would actually move it to the inward pin spots. The fan plug shouldn’t short on the heatsink when installed because the plug is abs obviously. And if the pins have enough clearance for a fan plug they have enough clearance to not short. They would have nearly the same risk of shorting to one another

A crooked heatsink seems like it is a impossible thing to plan for. If a heatsink is crooked it should be reseated. Heat it up and push it over or pop it off. Re seat it/etc. as you see fit. Or did they use a non heat sensitive adhesive?

@sphere, I understand why you don't want to move the location of 5V fan, but if are able to get creative with routing, it may be for the best.

1 in 3 of my SXL2 heatsinks are factory placed off-centre.
1 in 2 of my IBM 5x86c heatsinks are factory placed off-centre.

The clearance values I gave you are for heatsinks placed on centre. They have a thermal pad type of tape under them. To remove and re-secure the heatsink, I think, is not a move most people would be interested in. I wouldn't do it.

If someone buys an SXL2-66 and the heatsink is off-centred, thus cannot get the fan header on without a lot of bending, it can be avoided by putting the fan header on the outside of the overhang. 99% of people probably won't use those two pins from u1 and u2 as the application is very specific. Thus, the user with an off-centred heatsink would simply not solder on that inner header, or if already soldered on, simply cut the leads off. Moving the 5V for fan one position over makes the unit more versatile in this regard. If it simply cannot be done, then so be it. It is far better to have a smaller overhang than moving the header out further.

Here is an factory off-centred heatsink placed next to a factory centred heatsink. The offset shown is 1.0 mm.

For the on-centred heatsink, with alpha1, I noted previously we had 0.7 mm clearance. If you recall, I said for safe keeping, you can move that header 0.5 mm closer to the CPU. So now we only have 0.2 mm clearance for on-centred heatsinks.

Now that same heatsink/CPU placed into alpha1:

That amount of bend is BEFORE you moved the header 0.5 mm inward. You did this in order to make the overhang smaller. I am proposing that you keep the header and overhang as they are (smaller than alpha1) and just re-route 5V fan to the outer portion of the header. U1/U2 pins on the inside towards the heatsink, and MEMW#, 5V, GND on the outer edge of the overhang. If it cannot be done, or you don't want to deal with it any longer, that's perfectly understandable. Keep in mind that the 5V fan is only 80 mA. Will the re-routed traces be too narrow to handle that?

In general, if someone is going to use a 5V peltier and some massive heatsink/fan combination, they are better off running it directly from the molex, not the replica's header.

EDIT: In summary, I am weighing probabilities. The probability that someone is going to use u1/u2 AND has an off-centred heatsink is far lower than the user not using u1/u2 who has an off-centred heatsink.

Okay. Let me see if I can accomplish this.

you can always bend headers to fit whatever radiator you want, can even solder right angled header
sorry, I dont know the first thing about generating gerbers, not a layout engineer.

feipoa wrote:

I select 6-layer, it shows $2.50. This value is in disagreement with the advertisement of $20. Perhaps something is up again.

its actually $2 for 6 layer boards till January if they are small enough
"$2 limited-time special offer before 5th January 2023, that the board within 5cm*5cm"

feipoa wrote on 2022-12-12, 09:47:

rasz_pl, I have done as you suggested by making a low inductance ground tip for my oscilloscope probe. The probe tip's ground connection has a 4.78 mm diameter. I used a drill bit of 4.32 mm diameter to create the coil with solid 22 AWG. 6 full wraps. I spaced the GND lead out so that the distance from the tip to GND tip equalled the distance from the LT1528 OUT to GND.

thumbs up

feipoa wrote on 2022-12-12, 09:47:

Low_inductance_GND_on_x10_probe_3.JPG

it looks like most of that high frequency noise doesnt exist and was being picked up (emi) by the antenna you made with bad ground connection. More of a near field measurement 😀

feipoa wrote on 2022-12-12, 09:47:

It looks as if the low frequency waveform is still present and the Vpp is about the same as the noisier probe's connection.

fft? BW limit on/of? I wouldnt worry about low frequency fluctuations that much as long as sudden spikes are tamed

feipoa wrote on 2022-12-12, 09:47:

EDIT: I'm continuing to watch that eevblog guy's video on the probes and at around 6:40 it seems like he says to use x1 mode for measuring low voltages, which I'm assuming that's what we're doing if looking at 50 mV swings. Am I mistaken?

probe bandwidth

rasz_pl wrote on 2022-12-13, 01:27:

you can always bend headers to fit whatever radiator you want, can even solder right angled header sorry, I dont know the first […]
Show full quote

you can always bend headers to fit whatever radiator you want, can even solder right angled header
sorry, I dont know the first thing about generating gerbers, not a layout engineer.

feipoa wrote:

I select 6-layer, it shows $2.50. This value is in disagreement with the advertisement of $20. Perhaps something is up again.

its actually $2 for 6 layer boards till January if they are small enough
"$2 limited-time special offer before 5th January 2023, that the board within 5cm*5cm"

feipoa wrote on 2022-12-12, 09:47:

rasz_pl, I have done as you suggested by making a low inductance ground tip for my oscilloscope probe. The probe tip's ground connection has a 4.78 mm diameter. I used a drill bit of 4.32 mm diameter to create the coil with solid 22 AWG. 6 full wraps. I spaced the GND lead out so that the distance from the tip to GND tip equalled the distance from the LT1528 OUT to GND.

thumbs up

feipoa wrote on 2022-12-12, 09:47:

Low_inductance_GND_on_x10_probe_3.JPG

it looks like most of that high frequency noise doesnt exist and was being picked up (emi) by the antenna you made with bad ground connection. More of a near field measurement 😀

feipoa wrote on 2022-12-12, 09:47:

It looks as if the low frequency waveform is still present and the Vpp is about the same as the noisier probe's connection.

fft? BW limit on/of? I wouldnt worry about low frequency fluctuations that much as long as sudden spikes are tamed

feipoa wrote on 2022-12-12, 09:47:

EDIT: I'm continuing to watch that eevblog guy's video on the probes and at around 6:40 it seems like he says to use x1 mode for measuring low voltages, which I'm assuming that's what we're doing if looking at 50 mV swings. Am I mistaken?

probe bandwidth

90* header is a good idea

rasz_pl, thanks for your help here, but I don't really follow. It has been some time for me, but if I recall, we need something like 2.5x the bandwidth of the frequency under observance even begin to resolve it. There's a name for that law/rule, but I forget it. The signal I am looking at is 0.7 - 5.0 KHz in in the 50 mV range. In this case, wouldn't we want to use the x1 probe so that we are not attenuating our voltage 10x to the scope? And we are well withing the 6 MHz range of this probe. I think this is the message presented in that eevblog youtube post you directed me towards.

Regarding antenna's and picking up stray signals - when I probe my DC variable supply with a 3' long unshielded cable, I do not see any waveforms.

I haven't yet had time to watch the FFT video you provided. But I will present what I have in the second post. BW limit is off, but on did nothing.

I wanted to provide some update with the differences between the x1-standard, x10-standard, x1-low-inductance-gnd, and x10-low-inductance-gnd for the replica unit using the LP voltage regulator. Unit is powered on at sitting at DOS prompt, no clock doubling.

Here yellow is VCC3 with standard probe on x10, blue is VCC3 with x10 and low inductance GND probe. Is it because we have cut the voltages seen by the scope 10-fold that we are seeing this extra noise in the yellow signal, when compared with x1 standard probe? Low inductance probe cut out a lot of noise:

Low inductance GND probe also made the waveform more resolvable, it is really 5 KHz?

I then put CH1-yellow back to x1, but keep CH2-blue at x10 w/low inductance. The Vpp noise measured between the two is fairly agreeable. It seems to me that without a low inductance GND probe, it is better to use a standard probe in x1 for these measurements if you are after Vpp:

Next, I use the low inductance GND probe in x1 mode and tell the scope it is now x1. What is the true noise of Vcc3 then? Is it the low inductance probe at x1 32 mV, or in x10 mode at 72 mV:

Frequency still at 5 KHz:

Now, I adjust the voltage scale from 100 mV to 50 mV and compare both probe types at x1. If we cut-out the sharp peaks caused by a noisy ground from the standard probe, we can see how Vpp between the two are similar:

Still with 50 mV scale, I put the low inductance probe back on x10 mode. Is the real noise in VCC3 68 mV or 30 mV? From what the eevblog youtuber mentioned, it seems like x10 is attenuating the voltage too much and the scope cannot realise these small voltages properly. Please correct my understanding if I am not following:

Last check on freq:

I won't have time to watch the FFT videos until past midnight, but I have quickly grabbed what I think you were asking for. FFT/Hanning is part of the Math menu, not the probe menu. I took one shot at 1x zoom and Vrms, the other at 10x zoom and dbVrms.