BeebSCSI 7_7

for bbc micro/electron hardware, peripherals & programming issues (NOT emulators!)
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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Thu Aug 15, 2019 10:37 pm

Manually shorted the detect pin to ground, while typing mount, required 3 hands, and it works then. So reflow it is.

And the debug was indeed reporting no card.

Code: Select all

FAT FS: mmc_disk_initialize(): Executing
FAT FS: power_off(): Powering down SD card
FAT FS: mmc_disk_initialize(): ERROR: No card detected in socket
File system: filesystemMount(): ERROR: FR_NOT_READY - No SD Card reports not ready!


SCSI State: Resetting SCSI emulation
SCSI State: Firmware: V002.004
Emulation mode is Winchester (ADFS SCSI-1 hard-drive)

SCSI State: Bus Free
SCSI State: Information transfer phase: Data out

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Fri Aug 16, 2019 4:01 am

Great. Also you should upgrade the firmware; 2.5 is the current version (and contains some nice performance improvements for big files).

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Aug 16, 2019 6:40 am

It was after 2.5 firmware upgrade issue happened, so I downgraded it to see if that fixed issue. Obviously just s coincidence.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Aug 16, 2019 10:38 am

Original BeebSCSI now fixed and working again.

Of the two new BeebSCSIs I built, one works and the other one has the same not registering card issue. I did check that before I hooked it up but now pin 15 not going to ground also. So it appears if the connection is not great then the mechanical stress of plugging and unplugging the sdcard breaks it.

Just need to get the thrid beebscsi fixed and then run the stress test on all 3. Might try a physical stress test as well, plug and unplug sdcard a few hundred times!

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hoglet
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Re: BeebSCSI 7_7

Post by hoglet » Fri Aug 16, 2019 10:57 am

Elminster wrote:
Fri Aug 16, 2019 10:38 am
Of the two new BeebSCSIs I built, one works and the other one has the same not registering card issue. I did check that before I hooked it up but now pin 15 not going to ground also. So it appears if the connection is not great then the mechanical stress of plugging and unplugging the sdcard breaks it.
It is slighly awkward to re-solder the SD Card switch connections.

Here's a photo that shows the back of the SD Card socket:
IMG_1732.JPG
There are two connections: the left one is the ground connection, and the middle one connects though a large via to pin 15 of the microcontroller.

In my case, it was the connection in the middle that was dodgy. I reflowed it with a fine tipped soldering iron bit, in conjunction with a small amount of flux, and it's been fine ever since.

I should also say, it was hard to tell with a visual inspection that there was anything wrong.

Dave

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Fri Aug 16, 2019 11:12 am

If they are soldered correctly, you would need a silly amount of force to break the solder; try pulling a SMT cap off a board without heating it and you'll find out just how strong solder is. Basically, if you don't heat both the PCB pad and the pin of the component you will end up flowing solder only on one - with the pressure from the other pads you will then get an intermittent connection due to one half resting on the other - which will work/not work as the metal casing flexes from card insertions.

There are really only two sure-fire (simple) ways to solder hard to reach pins/pads with a high degree of accuracy: hot-air reflow or a fine tip iron under a soldering microscope.

Stress-testing a socket after soldering to see if your soldering was good is only going to result in faster wear on the socket. Get a cheap microscope from ebay (one of the cheap hand-help USB toys) - it's enough for a good post-assembly visual inspection (and is especially useful whilst learning to solder SMT devices).

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danielj
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Re: BeebSCSI 7_7

Post by danielj » Fri Aug 16, 2019 11:21 am

Elminster wrote:
Fri Aug 16, 2019 10:38 am
Original BeebSCSI now fixed and working again.

Of the two new BeebSCSIs I built, one works and the other one has the same not registering card issue. I did check that before I hooked it up but now pin 15 not going to ground also. So it appears if the connection is not great then the mechanical stress of plugging and unplugging the sdcard breaks it.

Just need to get the thrid beebscsi fixed and then run the stress test on all 3. Might try a physical stress test as well, plug and unplug sdcard a few hundred times!
If you checked just by installing the firmware, it won't tell you if that pin was well connected. The firmware will install regardless of the insert-detect.

d.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Aug 16, 2019 11:28 am

danielj wrote:
Fri Aug 16, 2019 11:21 am
Elminster wrote:
Fri Aug 16, 2019 10:38 am
Original BeebSCSI now fixed and working again.

Of a the two new BeebSCSIs I built, one works and the other one has the same not registering card issue. I did check that before I hooked it up but now pin 15 not going to ground also. So it appears if the connection is not great then the mechanical stress of plugging and unplugging the sdcard breaks it.
If you checked just by installing the firmware, it won't tell you if that pin was well connected. The firmware will install regardless of the insert-detect.

d.
Yep. I discovered that from the other board. This was tested with a multimeter.
Last edited by Elminster on Fri Aug 16, 2019 11:38 am, edited 1 time in total.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Aug 16, 2019 11:33 am

simoni wrote:
Fri Aug 16, 2019 11:12 am
If they are soldered correctly, you would need a silly amount of force to break the solder; try pulling a SMT cap off a board without heating it and you'll find out just how strong solder is. Basically, if you don't heat both the PCB pad and the pin of the component you will end up flowing solder only on one - with the pressure from the other pads you will then get an intermittent connection due to one half resting on the other - which will work/not work as the metal casing flexes from card insertions.

There are really only two sure-fire (simple) ways to solder hard to reach pins/pads with a high degree of accuracy: hot-air reflow or a fine tip iron under a soldering microscope.
I do have all the gear, but at the time I didn’t realise it would be a pain, or I would have got the solder paste out of the fridge. Although saying that those connectors were soldered on all 3 boards in Sept last year, just I didn't finish boards 2 & 3 till this year. Was only the second surface board I had done at the time, done a dozen or so since, so wouldn't have had the experience to know that it would be an issue. I don’t plan to make more anyway, but other people might find info useful. [Edited]

I have ripped off usb connectors, but only by accident.
Last edited by Elminster on Fri Aug 16, 2019 11:57 am, edited 4 times in total.

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Aug 16, 2019 11:40 am

hoglet wrote:
Fri Aug 16, 2019 10:57 am
Elminster wrote:
Fri Aug 16, 2019 10:38 am
Of the two new BeebSCSIs I built, one works and the other one has the same not registering card issue. I did check that before I hooked it up but now pin 15 not going to ground also. So it appears if the connection is not great then the mechanical stress of plugging and unplugging the sdcard breaks it.
It is slighly awkward to re-solder the SD Card switch connections.

Here's a photo that shows the back of the SD Card socket:
IMG_1732.JPG

Dave

You board looks different? It that one of the mini ones?
Last edited by Elminster on Fri Aug 16, 2019 11:56 am, edited 1 time in total.

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simoni
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Re: BeebSCSI 7_7

Post by simoni » Fri Aug 16, 2019 11:55 am

Hoglet's board is a 7_5 PCB - the 7_7s have a more compact Molex microSD socket that's easier to solder (7_7 is the current PCB release version).

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Elminster
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Re: BeebSCSI 7_7

Post by Elminster » Fri Aug 16, 2019 7:12 pm

Lucky I don't have the hard to solder sdcard slots then.

All 3 working now.

Soak tested the first one for 2 hrs using the basic program (only a couple of minutes doing the writing). Some turning off and on again, and reinserting card a few times (dont worry I am not doing it hundreds). Played with transfer and the beebscsi rom, all work fine. I would say that is a pass.

Onto next 2 cards now. All looking good thanks.

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