[4world]

First, I need to solder the blown PTC fuse and since it literally exploded, the pads/traces in that area are gone.

Second, I may need to replace other blown components (like maybe the LM2596), zener, etc. <– This I can figure out if you confirm that the only differences in the above two layouts is just the copper area.

Ray, thank you again for your excellent support.

[4world]

The files you point to are the same ones as I downloaded.

Please see the attached two pictures — one is a screenshot from EagleCAD with all relevant layers turned ON and the other is the OSPi v1.3 board that I have. See the arrows and you can clearly see that the two layouts are different at least as far as copper areas go.

Awaiting your response.

Thanks.

Attachments:

1. 

   EagleCAD-view-OSPi-v1.3-marked.png
   

2. 

   Actual-OSPi-V1.3-board.jpg
   

[4world]

Thanks Ray. Please answer the ultra-important message above as I am stuck without it. Repeated below —

The github PCB layout files for OSPi V1.3 (.BRD) do not match the actual V1.3 board I have. E.g., the BRD file doesn’t show copper plane areas even with all layers turned ON in Eagle CAD. In fact even the traces are different.

With the literal blow out of the PTC fuse which has ripped apart some traces also, I need to see the actual layout so I can repair the tracks. Where is the accurate layout file or image?

Thanks

[4world]

Ray,

The github PCB layout files for OSPi V1.3 (.BRD) do not show the copper areas that can be seen on the actual V1.3 board. In fact the copper traces are also quite different.

With the literal blow out of the PTC fuse which has ripped apart some traces also, I need to see the actual layout so I can repair the tracks.

Please help…

Thanks

[4world]

I am surprised too. I will investigate further why the fuse blew by doing some calculations for the cap, current, etc.

The reason I need the 5000uF cap is as said before: I have a 120VAC pump motor that is turned on by the RPi+OSPi. When the pump turns on, it sucks a large AC current which momentarily drops the 120VAC big time. This drops the 24VAC which in turn drops the +5VDC momentarily — this dip is enough to cause the software to go haywire. I don’t have my storage scope here so won’t be able to investigate exactly how big the dip is but will in any case try using a smaller cap to see if that does the job.

Do you know where I can get a replacement for the 1.5A PTC fuse or is it generic enough to get at Radio Shack, Amazon, etc.?

Thanks for your time.

[4world]

Okay, I got EagleCAD running – thanks for the advice (didn’t know it was freeware).

One question that would greatly help–

The BOM for v1.3 is not at http://goo.gl/4Nrvb and the EagleCAD silk screen also doesn’t say anything on the blown part (see attached – the charred area between LM2596S-5.0 and 5.6V zener (D3). Is this a fuse and what value and part #? No info on the sch. file either.

I blew this part *probably* because I added a nearly 5000uF cap on the +5V?? Maybe it’s the surge current to charge the cap that blew it although I am surprised since it shouldn’t be that much. I will try moving this cap before the LM2596 to see if that might help. (It seems like the 2A fuse also blew — totally inexplicable!)

Had to do this since there is a 120VAC pump motor that puts a dip on the line voltage that travels all the way to +5V and freezes the RPi and other electronics.

Any technical advice would be deeply appreciated.
Thank you

Attachments:

1. 

   Damaged-board.jpg
   

[4world]

Hi Ray,

Please see the above old thread. I don’t have any CAD software and just need: a) The silk screen and b) The traces (both sides) layout.

Other older versions of the above have PNG and/or JPG files on your repository but not this one (v1.3). May I PLEASE request you or someone else to please

upload PNG file for the silk screen and JPG for the traces

for the above.

I have a blown part on my board and I am unable to tell what part it is so need your help. I travel overseas most of the times so noticed this blown part on my current U.S. trip. Please reply soon.

Thank you for your help in advance. You have always been wonderful in your support!

-Ashim

[4world]

I am using the ULN2803 (which has 8 Darlington pairs) for other functions (like driving relays) and since I had a spare Darlington left on it, I thought of using it to drive the triac.

I don’t care about isolation so this will work fine. Just need to know if the gate will sink high amounts of current into the OC output when it’s active (low) without a series resistor. If so, I will use the series resistor but that will add 220+500 ohms to +5V when the ULN2803 output is high — hopefully that won’t be insufficient current into the gate of the triac.

I am ready to cut traces and solder, so the above answer would greatly help me.

Thank you.

[4world]

Hi Ray and thank you for such a super prompt response.

I had already checked that place. There are only 3 files related to Ver 1.3 there – a SCH, PNG and BRD. I cannot open the SCH or the BRD files since they are probably source files of OrCAD/Cadence or some other similar schematic and board layout program — I needed a PNG/JPG to view the silk screen layout just like you provided the PNG for the schematic.

Thank you for your help.

[4world]

Thanks Ray. Just one more quick question please:

What is the spare current (after you subtract what’s needed for the OSPi) that I can draw from the +5V regulator LM2596S for my external circuitry?

I have a hefty 24VAC 3A (75VA) transformer and am using only 6 regular sprinkler valves so there’s plenty of capacity there. From the LM2596 spec, it seems like it should be able to do 3A but wanted to confirm.

Your customer support is dearly appreciated!!

[4world]

Thank you Ray! I truly admire your stamina to reply to nearly every email and forum post, yet still be able to push the OS project forward.

3.3V from HC595??? The schematic ospi_v13_sch.png from your website shows there’s a +5V regulator that also feeds that chip. So am I missing something? HC595 running even at 4.5V should output around 4V min.

The idea to put an NPN in place of the triac is great! I was going to leave the triac in and just take a wire from the HC595 output to feed into a ULN2803 darlington. If I am unable to replace the triac with an NPN (and the additional resistor), then the 3.3V (if is really that) should still be able to easily drive the ULN2803 (VIL min = 2.4V @ IC=200mA).

Awaiting your reply on the 3.3V question. Thank you again!

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