Thread: Home Switch Problem
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23-03-2017 #21
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24-03-2017 #22
Hi John sorry for the delay in replying iv'e just got in from work. The top photo of the bob you've labeled is correct, and the led is lit when powered up
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24-03-2017 #23
Hi Kev
going by the LED indicators the board has the DC supply OK
and the onboard 5V regulator is working
so I would of expected the board to work
with out a board to test my self I'll have to do another web search to see if I can find any more information
John
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24-03-2017 #24
Thanks John I appreciate you doing all this,
Kev
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24-03-2017 #25
Going back to this photo, my calcs based on the 1k resistor, means the opto should have 24V on the pin you've marked as 5V. At 5V, the 1k resistor would limit the current to roughly 3mA, whereas 24V would give roughly 22mA. Having had a look at the datasheet for the opto, it's expecting 20mA with a forward voltage of 1.2V.
Kev, have you measured the voltage at the top left pins on the optos?
Try using the bottom pin on the connector for gnd, and also the main power in gnd for the voltage measurements, just in case it's a gnd fault, not a positive supply fault.
If there is no voltage showing, is there power at the fan connector/is the fan working?
Would it be possible to get a photo of the underside of the board, so we can see where the power supply feed to the opto comes from?
Given the layout, I'd think the optos would take a feed from the same supply going to the fan connector, but without seeing the underside of the board, that is purely a guess.Avoiding the rubbish customer service from AluminiumWarehouse since July '13.
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25-03-2017 #26
Hi John, I think I'm going to replace my bob with an upgrade. What would you recomend ?
Kev
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26-03-2017 #27
Hi Kev
I'm not sure what to recomend
I was going to recomend CNC4PC's C10 breakout board
but looking at their web site they have changed the construction
the versions I had seen had the IC's in sockets
making it easy to repair if something went wrong
the latest version is like this
this chinese BOB others have had problems with
I have reverse engineered to find out why it didn't work as I expected
it turns out that the 74hc14 IC used to buffer the inputs doesn't have the supply pin connected !!!!
in a quick web search this is the closest to your BOB I have found ( may need an extra power supply)
boards like this with opto isolated outputs are not ideal when the stepper drivers have opto isolated inputs
breakout boards with LED indicators on the inputs could be an advantage
at least you can see when the switch is operated
low cost chinese board with LED input indicators
John
PS
from Australia
this MB02 from Homann Designs is a possible alternative to CNC4PC's C10
Last edited by john swift; 26-03-2017 at 07:51 PM. Reason: add ref to MB02
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26-03-2017 #28
Hi John, I bought a bob a while ago from ebay, it looks very similar to the one in your photo, but i've never used it because someone told me it wouldn't work with my drivers, or steppers, can't quite remember which. Is that true ?
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26-03-2017 #29
Personally, I'd try fixing the one you have first.
It seems to be a reasonable spec, in that it uses 24V inputs, which is far better than using 5V which most BOBs do.
It's most likely something simple, so if you can get a photo of the underside, we should be able to workout the area of the problem.Avoiding the rubbish customer service from AluminiumWarehouse since July '13.
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26-03-2017 #30
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