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Outlets on power board not working
#1
Outlets on power box not working.
I purchased this off someone else, the power box was working but outlets 3-4-5 no longer do.
The power box was assembled, looks like a good job, I built the robotank board for the pi4

I checked the cable was straight through pin to pin between robotank and powerbox.

3 on will not turn off
4 off will not turn on
5 on will not turn off

using reef pi to control the equipment outlets- and changing the plug on robotank plug 1 and 2 - power box is the same so i can assume its the power box.
what can I check and what needs replacement? or is the robo tank signal locked the outlets on / off?

NZ sockets in the power box, some have trouble inserting plugs because of the internal springs, so while I am at it I would like to replace them.
Might as well do all 8.
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#2
Just to add - I unplugged the cable from the robotank to powerbox and measured the 8 x sockets.
They all have 236VAC.

Not much current (guess as I am no electrical wiz) as it will not turn on a light when off but there is voltage there.
Some of the soliniods will not click on and off...
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#3
Do you have my power bar? It sounds like it as you have voltage on the outlets but no current. This is caused from the snubbers (yellow cap and large resistor), it allows a small amount of current through when off so you'll always read voltage but it drops once something is plugged in and outlet is off. When DB9 is unplugged all outlets turn off.

Try checking the voltage on all 8 channels in DB9 out of controller without power bar plugged in. When outlet is on in reef-pi you should get 3.3v and 0v when off. Here's the pinouts.

https://docs.google.com/document/d/1gXgB...=h.2et92p0

The signal pins on DB9 are a straight run from Pi so yeah can't imagine 6 pins just quite working. Also hard to imagine 3 outlets quit at same time so it sounds more like a software setting. Maybe try deleting the outlets from equipment tab, then delete connectors, restart reef-pi and add them back.
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#4
Hi Rob - yes your box. Good to know there is meant to be voltage but No current.

I will do the tests tonight...

The pwoer box just acts funny some times a relay will click on and off - other time no.
Seems more like a power box issue but maybe not.

The reef pi seems to be working as it should.

thanks
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#5
Sounds good, once you do the test we'll know for sure where the problem lays. If all pins read 3.3v when turned on the controller is fine and we can go from there.
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#6
3.3v output on all outlets as described above.
Both plugs 1 and 2.

With all outlets turned on.
So it is the box?

Oh and thanks!
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#7
Thanks, seems like the problem is in the power bar.

I attached an image where to check voltages in power bar but do be very careful with all that 240v floating around.

Two sections to check, first I marked the +5v pin on each relay in red and the GND pin in black, when all outlets are on each relays should read 5v at those points. If you read 5v but relay doesn't click then it's a relay issue, if you don't get +5v it's something else.

The other section I circled in black, notice it has a grey point marked, this is the common ground, not to be confused with all the ground points on relays. When checking voltages in this section use that point for ground probe.

First check voltage on resistors on input side, I drew a red line across each bank of 4 resistors on each side of DB9. You should see 3.3v going into each resistor, this is what's coming from controller. Then check on other side of resistor and you should have voltage, if not the resistor is the problem.

See what happens with these checks and we will go from there.

   
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#8
I have tested as suggested.

There is voltage on both sides of the small resistors.
3.2VDC on one side on all 8 outlets.

The other side of the small resistor.

R10 - 0.85
R11 - 0.94
R12 - 0.96
R13 -0.96

R6 - 2.69
R7 - 2.69
R24 - 1.00
R8 - 2.69

voltage on the relays tested on both power bar 1 and 2 on Robotank
Relays with low voltage do not work, there is 230VAC on all outlets but I cant measure current, when off there is low current as discussed earlier.
I plugged in a light to test if the outlet is actually turning power on and off.

socket 1 - 2.04 & 2.3 VDC  - outlet does not work - reads 230vac -
socket 2 - 2.98 & 3.05 VDC - outlet does not work, is on, I can turn it off but will not turn on again. - reads 230vac
socket 3 - 4.29 & 4.3 VDC - outlet - on always - can not turn off - reads 230VAC
socket 4 - 1.45 & 1.89 VDC - outlet always off - reads 230vac
socket 5 - 4.61 & 4.62 VDC - outlet always on - reads 230vac
socket 6 - 4.99 & 4.99 - outlet works
socket 7 - 4.99 & 4.99 - outlet works
socket 8 - 4.99 & 4.99 - outlet works

Unfortunately I had to break the case / plastic board where 2 x screws screw in as i could not access those 2 x screws.... I managed to undo the rest.
When this problem first appeared it was only 1-2 outlets - now it is 5 and I am sure all 8 worked when I first tested it.

Hope this helps.
thanks
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#9
I'm not really sure what to think, I'm guessing the resistors with low voltage are the 5 outlets not working?

It seems to be a resistor issue but not sure why or what's causing it. The resistors help protect the circuit and only thing I know that would damage it is if ground is connected to a pin. If a Null cable is used ground and outlet 5 are switched so the resistor for outlet 5 would be damaged but no cable can cause 5 to be.

Any chance you have a resistor of 220 ohm - 1k?

If not you could try removing say R10 and then bridge the pad but like that there is no protection for the Pi Pin so I wouldn't keep it like that if it works as something strange is going on. Others have used it with 230v so I don't think that's the problem.

Try this and I'm thinking about in the meantime.
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#10
HI Rob,
I have 300 ohm resisters, and can get more tomorrow

R10

With this in place the voltage went from 0.85vdc to 1.5vdc - did not work -
Bridged the resistor and outlet 4 works.

I soldered the resistor in place tested it, then bridged it.

[Image: 8RrZeRL.jpg]
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#11
Hi Dukereef, in the picture on R10 is there 3.3v when on and 0v when off?

1.5v is better but the transistor probably needs about 2v to switch. Any chance you have other resistor values to try?
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#12
(09-15-2020, 12:35 AM)Rob F Wrote: Hi Dukereef, in the picture on R10 is there 3.3v when on and 0v when off?

1.5v is better but the transistor probably needs about 2v to switch. Any chance you have other resistor values to try?
[quote pid='5727' dateline='1600151731']
Yep I will go to the shop tomorrow and buy other resistors. what do you recommend?
[/quote]
2.8v on bridged - 0vdc off (38.0 mV)
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#13
Maybe get a few values up to 4.7k but that's getting high. It should have worked with the 300ohm, I have 1k on them.

2.8v sounds low like something is pulling it down. I think you mentioned when you checked the input of resistors you saw 3.2v so it's not voltage drop at 2.8v. I wouldn't leave it like that too long in case it hurts the Pi pin.

Since you have the resistor off the pad can you set you voltmeter to check current and touch probe to each side of resistor pad. It should be very low, I would think under 5mA but I have a feeling it's high and pulling the voltage down, not good. I believe the pin on Pi can tolerate about 20mA. The resistors do die if too much current goes through so maybe that's what's happening. Still not sure why though, maybe just a faulty PCB. There are no more components involved, just what you see on power bar.
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#14
I will get
1k, 3k and 4k resistors and do the checks after work.
Thanks
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#15
if they have 220ohm that would be better than 4k. Less voltage will come out the resistor the higher it goes.
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#16
I have not changed the resistor as you said the 300 should work... now removed again.

2.8v sounds low like something is pulling it down. I think you mentioned when you checked the input of resistors you saw 3.2v so it's not voltage drop at 2.8v. I wouldn't leave it like that too long in case it hurts the Pi pin. - from memory with the 300 resistor I had 3.2v - bridged 2.8v - I am only turning on the power board for testing then turning it off.

Since you have the resistor off the pad can you set you voltmeter to check current and touch probe to each side of resistor pad. It should be very low, I would think under 5mA but I have a feeling it's high and pulling the voltage down, not good. I believe the pin on Pi can tolerate about 20mA. The resistors do die if too much current goes through so maybe that's what's happening. Still not sure why though, maybe just a faulty PCB. There are no more components involved, just what you see on power bar.

Ok removed the bridge and tested the current.
Turned off - 0.8MA
Turned on - when the probes touched the resistor pads the outlet 4 turned on with a click and read 11.1MA

Hope this helps... where to from here?
thanks!

I did notice what looks like solder tracks... would this affect anything?
in the circle and D1 to the resistor etc
I removed them but if made no difference

[Image: MOVkGzi.jpg]

[Image: 5zeZ5Kv.jpg]
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#17
Sorry I'm confused, if you get 3.2v or even 2.8v with 300 ohm resistor it should switch, does it not? That's plenty of voltage to turn on the transistor.

11 mA sounds good so the pin isn't overworking like I thought it could be.

Those solder tracks aren't good, I'll need to be more careful but I don't think the power bar one will cause a problem as it does switch but yeah not good.
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#18
Hi Rob
I got 3.2 - with the 300 resistor one side - did not work
2.8 bridged - worked.

next move?
thanks.

Hi Rob can you please email me on arron.hooper@xtra.co.nz
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#19
Hi Arron, so other side of resistor you didn't get any voltage? That's probably what I misunderstood.

Sadly I think a new board is needed, I don't know what else to suggest, everything you've done is correct so why voltage isn't get through the resistor is a mystery, especially as they have been dropping a 2-3 at a time. As you got 5v on relays we know the power module is ok so nothing else but faulty board.

I'll send a message, maybe edit and remove your password as bots roam the site and might pick it up.
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Current time: 10-20-2020, 01:10 AM