Heatermeter Aux. Thermocouple And two probe board V6.1(Final Version)


 

RalphTrimble

TVWBB Diamond Member
There is NOTHING on this board for the servo except for a connection from the CAT5 jack to the pins where you plug the servo, no electronics whatsoever. So, as long as you have solid continuity between the CAT5 and pin header your servo problem is not on this board.
The only possibility for this board to cause a servo issue would be if there was some sort of short or bad component (in the TC amp circuit) that is drawing down the 5V and causing a brown out scenario, or a bad connection where the plug meets the jack on either the CAT5 cable or servo header.
 
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John Bostwick

TVWBB Wizard
Yep, Ralph is correct.

The only thing you can do really is a continuity check. The adapter board just passes along the connections
 

John Parkinson

New member
Hi Both,

thanks for replying. From looking at the board I was thinking that it was just a direct connection from the RJ45. So i've tried 5 different servos and 3 different CAT5 cables between 3ft and 30ft. All behave the same with the servo sort of working but behaving erratically. All voltages appear to be correct at the servo and looking at the PWM signal on the scope appears correct.

The strangest part is that if i take the servo and solder it directly to R21, +5V and GND (on the HM 4.3 without any cat5 connected) then it behaves correctly. Very strange....

Any ideas?
 

RalphTrimble

TVWBB Diamond Member
I would suggest this...
Connect a servo directly to the wires on a single ended CAT5 cable, see if it works there like when soldered to R21. If not then look at Q5, that is the only component that could be at issue (other than a bad solder joint or solder bridge). Also check the pins inside the CAT5 jack on the HM board to see if they are bent, corroded, debris inside there etc.
If it works fine hard wired to the cable then I would look closely at your CAT5 connector on the Aux board for the same as above, and check solder on the CAT5 jack and servo header. If that all checks then measure +5V on the Aux board and see if it is dragging down? If its low then maybe you have some sort of short/solder bridge/misplaced component in the TC circuit on the Aux board.
 

John Parkinson

New member
Hi Ralph,

Fixed it. It seems to be the volts drop across the tracks between the RJ45 and the servo. When the servo's trying to move it was dropping down to ~4.2V so i've soldered some additional wire between the RJ45 and the servo header and all seems to be well. I've no idea how much current my batch of MG90S servos are drawing but i'm guessing it's more than most other ones if nobody else has this problem.

It might be worth increasing the width of the tracks between the RJ45 and the servo if the board is ever re-spun?
 

RalphTrimble

TVWBB Diamond Member
What is the Amp rating on the PS you are using? Perhaps the extra resistance of a couple connectors, wire, traces etc is burning off just enough power to brown things out a bit. I always recommend using 1.5A or better PS when using a servo and blower just to be on the safe side...
 

John Parkinson

New member
It's a 2A PSU. If i measure the voltage on the output of the HM DC-DC then it's solid at 5V even when the servo is moving. There's maybe 0.1V or so dropped down the CAT5 but most of it is dropped across the inch of track between the RJ45 and the servo header (i'm soldering the servo leads to the board).

Not sure how the track widths compare on the HM PCB compared to the aux TC board?
 

Jeff.Ro

TVWBB Member
Thick Film Resistors - SMD 0805 10Kohms 5% AEC-Q200
Thick Film Resistors - SMD 0805 1Kohms 5% AEC-Q200
Multilayer Ceramic Capacitors MLCC - SMD/SMT 0805 0.1uF 100volts Y5V 20%

Some of the SMD components from Mouser are backordered... Anyone smarter than me know of acceptable substitutes without a 16 week lead time!

Here's the mouser project.
 

RalphTrimble

TVWBB Diamond Member
any SMD 0805 resistor with those values will work, should be very easy to find an alternate part. You might even find the same part available in a different package style. Take a minute to browse the mouser website and you should find what you need. Load the product page for the out of stock item then put the specs you see there into the filters on the following mouser pages.

Caps:
http://www.mouser.com/Passive-Compo...er-Ceramic-Capacitors-MLCC-SMD-SMT/_/N-bkrdv/

Resistors:
http://www.mouser.com/Passive-Compo...Resistors/Thick-Film-Resistors-SMD/_/N-7gz42/
 

John Bostwick

TVWBB Wizard
Yep, mouser stock is pretty fluid and they usually have something on backorder. Just like what Ralph said any of the same value 0805 package parts will work, so long as they have the same value, 1k 1n, 10n, 10k ect......... Mouser has a pretty good part comparability tool on their site, unlike many other sites.
 

Jeff.Ro

TVWBB Member
Anyone have one of these V6.3 boards laying around? Don't know what I'd do with two extra laying around. Let me know, I'd pay a couple bucks to ship it out rather than the $7/three at OSH park.

Thanks!
 

John Bostwick

TVWBB Wizard
Anyone have one of these V6.3 boards laying around? Don't know what I'd do with two extra laying around. Let me know, I'd pay a couple bucks to ship it out rather than the $7/three at OSH park.

Thanks!

I sale them for $30 complete, if you like to have built. If not, PM me either way.
 

RCDavis

New member
Will the adapter board work for the blower only, without modification of the HM board? I'm not terribly confident with the components on the HM board and wouldn't want to do something I can't repair -- which is anything :)
 

Ben S

New member
So, I can't figure out how to send a message, but I would love to buy a prebuilt PCB. I've got my heatermeter ip and running and a roto damper, but now I think I'd rather have the RD with a PCB in it....
 

 

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