USB connectors

If you're having problems with the hardware of a DM41X or DM42, post about them here.
grsbanks
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USB connectors

Post by grsbanks »

A few of you have reported that you've had problems with USB connectivity so we looked at this in greater detail.

The DM42's USB connector is close to the tolerance regarding its distance to the edge of the calculator. If a cable is used of which the length of the actual connector is also close to the tolerance then the casing around it might well come into contact with the DM42 if that casing is a bit bulky. This could prevent you from inserting the connector far enough. We're only talking about tenths of a millimetre here but that's clearly enough to get in the way.

In order to test this theory, try removing the rear case and connecting the USB cable again. If you now have a stable connection then connector length/recess is indeed the problem.

In this case, one solution is to shave some of the plastic off the top part of the connector housing on your cable. Observe the photos below:

BEFORE:
Image

AFTER:
Image
There are only 10 kinds of people in the world: those who understand binary and those who do not.
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4ster
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Re: USB connectors

Post by 4ster »

In case someone else finds that they need to buy a connector: What you are looking for is a cell phone charge/sync cable; Micro-B to A, USB 2.

I was looking in the "Computer Cable" section in my local electronics Big Box store and couldn't find it. There were lots of USB varieties but nothing with a Micro-B on one end. I asked a sales person if they had another area with cables and, seeing my "cell phone" (DM42) in my hand suggested the cell phone cable section. I hadn't thought to look there.
Steve
Acquired in order: HP 41CV, CMT MC-GPS, HP 41CX, DM41, DM42!
redglyph
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Re: USB connectors

Post by redglyph »

Thanks! I realized after spending a lot of time with the driver that it was the problem, and reached the same conclusion: I tried by opening the case to get a proper connection and it worked.

Without that, I get the icon on the calculator telling me it's connected to an USB power source, but still it fails to connect, which is *very* confusing (it's too easy to believe it's an USB driver issue on Windows). So don't get fooled by that!

If I push a bit on the connector, sometimes it works, but I'm really not comfortable to proceed like that :|

I'm not pleased, especially after seeing the DM42 has key debouncing issues, but I hope at least it'll help if someone else is confused by the USB icon.
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groenewe
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Re: USB connectors

Post by groenewe »

Make sure you have a good and proven working USB data cable and not only for POWER delivery. Yes those cables exist and put the most avid user sometimes in a difficult spot and in hindsight caught off-guard. I had this twice with a borrowed cable in the office here. They need to be good otherwise no data exchange.
cdmackay
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Re: USB connectors

Post by cdmackay »

I had read that the power pins of the USB connection may be slightly longer, so that power is up before the data pins are connected. Whether that's true or not, I don't know, and I think it referred to the USB-A (i.e. PC/host) end.
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M0oml
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Re: USB connectors

Post by M0oml »

redglyph wrote:
Tue Jan 08, 2019 3:22 pm
Thanks! I realized after spending a lot of time with the driver that it was the problem, and reached the same conclusion: I tried by opening the case to get a proper connection and it worked.

Without that, I get the icon on the calculator telling me it's connected to an USB power source, but still it fails to connect, which is *very* confusing (it's too easy to believe it's an USB driver issue on Windows). So don't get fooled by that!

If I push a bit on the connector, sometimes it works, but I'm really not comfortable to proceed like that :|

I'm not pleased, especially after seeing the DM42 has key debouncing issues, but I hope at least it'll help if someone else is confused by the USB icon.
On the USB specifications the power pins in the connector should be slightly longer than the data pins so it's possible to connect to charge and not connect the data pins
redglyph
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Re: USB connectors

Post by redglyph »

M0oml wrote:
Thu Jan 10, 2019 12:12 am
On the USB specifications the power pins in the connector should be slightly longer than the data pins so it's possible to connect to charge and not connect the data pins
Thanks!

That would explain it, however when it happened it was confusing. Even more so because I had previously connected it with another cable and by luck it didn't have that issue.
TwoWeims

Re: USB connectors

Post by TwoWeims »

I am very happy to report that the USB Connector on my DM41X Beta Unit has been moved so that it will connect without trimming the connector!
Thank You.

I don't suppose that a retrofit of my DM42 is possible...
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pcscote
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Re: USB connectors

Post by pcscote »

TwoWeims wrote:
Wed Feb 05, 2020 3:06 pm
I am very happy to report that the USB Connector on my DM41X Beta Unit has been moved so that it will connect without trimming the connector!
Unfortunately not for me, I had to trim my USB connector (like I did with the one I am using for my DM42).
[DM1x/DM1xL/DM41/DM41L/DM41X/DM42]
TwoWeims

Re: USB connectors

Post by TwoWeims »

Hmm...
It is time to crack this thing open to see what the difference is...
IMG_4019.jpg
IMG_4019.jpg (84.24 KiB) Viewed 10051 times
It looks like the DM41X Connector is mounted slightly further back than on the DM24. It doesn't look intentional.
Maybe a different part from a different manufacturer or just a bit of soldering serendipity...
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