DM42 "USB Disk Mode" works at random - mostly not at all

If you're having problems with the hardware of a DM41X or DM42, post about them here.
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rudi
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DM42 "USB Disk Mode" works at random - mostly not at all

Post by rudi »

Do I need a Windows 10 driver for the DM42?

Since I got it, it's been very sporadic weather I could get access to my DM42 on Windows 10.
Usually I just have to retry 2-3 times, then the connection succeed, but now I have tried a dozen times without any luck...
I have tried several cables, they all work find for on other hardware, so I doubt very much it's a cable issue.
The USB connection icon next to the voltage indicator on the DM42 is also showing all right.

I am running DMCP v3.22 (IFC 03.15), DM42 v3.20, Free42 3.0.5.
I have tried restarting Win10 several times, and switched the DM42 on/off several times as well.



Any suggestions?

Once in a while, Windows shows this:
DM42_not_connecting.jpg
DM42_not_connecting.jpg (21.42 KiB) Viewed 2933 times
/Rudi

DM-42 (s/n 06999), HP-42S, HP-35s, HP-11c, HP-32SII (ex HP-41CV, ex HP-75C, ex HP-48G + a lot, really lot of a accessories)
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rudi
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by rudi »

Update: If I press the USB plug hard, like really hard, into the DM42, it connects. I use this same cable for several other devices, so I don't think the cable is broken. Have also tried the same with my other cables. It's the same, need to apply a lot of pressure.
/Rudi

DM-42 (s/n 06999), HP-42S, HP-35s, HP-11c, HP-32SII (ex HP-41CV, ex HP-75C, ex HP-48G + a lot, really lot of a accessories)
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Florian
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by Florian »

This is (unfortunately) a known issue with the DM42. The micro-USB socket is sitting too far inside the case so that a USB cable with a standard connector will only barely make contact. Just for power supply is usually fine, those contacts are a little bit longer. But to get the data lines also connected some effort is necessary. There seem to be some cables that expose more of the plug so that they can be pushed in further. Also, some people cut away away a bit of the molded rubber from the connector to have an easier time connecting to the DM42 PCB.
rprosperi
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by rprosperi »

Here is a link to a USB cable with extra long micro-USB tip:

https://www.amazon.com/gp/product/B013CX6XO8

Alternately, depending on the cable you currently use, it may be simpler to trim the plastic "head" that surrounds the connector to allow it to seat deeper into the socket, but this is not feasible on some cables.
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
Thomas_ER
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by Thomas_ER »

Here is a solution like mine, to slightly modify your existing USB cable,
you need only a sharp knive. With good pictures!
viewtopic.php?p=3804#p3804

Good luck!
[ HP48/49/50/42S/WP34/HP Prime/ DM42 (#00185+00318) ]
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rudi
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by rudi »

Thanks for the advice Thomas, I'll try a sharpie and remove a slice at the top
/Rudi

DM-42 (s/n 06999), HP-42S, HP-35s, HP-11c, HP-32SII (ex HP-41CV, ex HP-75C, ex HP-48G + a lot, really lot of a accessories)
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Thomas_ER
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by Thomas_ER »

rudi wrote:
Mon Dec 20, 2021 11:03 pm
Thanks for the advice Thomas, I'll try a sharpie and remove a slice at the top
I keep my fingers crossed for you / your cable!
[ HP48/49/50/42S/WP34/HP Prime/ DM42 (#00185+00318) ]
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rudi
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by rudi »

Yes - both the sharpie, cable, calculator and my fingers survived the operation, and now the DM42 connects every and each time!

My cable was blocking both above and below. I tried to first remove a wedge at the top, but that wasn't enough, so I removed all the way arround the socket. Approximatly 3 mm had to go.

Image
/Rudi

DM-42 (s/n 06999), HP-42S, HP-35s, HP-11c, HP-32SII (ex HP-41CV, ex HP-75C, ex HP-48G + a lot, really lot of a accessories)
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Panchdara
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Re: DM42 "USB Disk Mode" works at random - mostly not at all

Post by Panchdara »

Probably the reason why that socket is so far back? Health and Safety. Someone in an office with no experience has dictated that the socket needs to be x-mm inset.... then again, the chinese are not part of that rule and make the cables... I'm shakin' my hed!
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