Instructions for the SMD part?

Juho A

TVWBB Member
I finally have everything except for the servo, and I am ready to get started soldering. However, I noticed the wiki doesnt have (or I cant find) instructions for the SMD part of board assembly, and Bryan's excellent video of the assembly starts with a board that has the SMD parts on it.

Is there separate instructions for the SMD assembly part?
 

Dupree

TVWBB Fan
Is this a new 4.3/4.2 board? And are you referencing the thermocouple components? My understanding, and experience assembling a 4.3, is the thermocouple components come premounted to the board.
 

RalphTrimble

TVWBB Diamond Member
Boards can be purchased with the SMD thermocouple amp parts pre-populated but you can also order boards without the SMD stuff, so depends on what you purchased.
I can't recall off hand how well the SMD parts are marked on the board, but parts are generally pretty much marked, so you might be able to get away with just following what is printed on the board. If I recall correctly its just caps and resistors, which have no polarity, and the TC IC chip which is what you are going to need to pay the most attention to... It has a dot in one corner if I recall correctly, and there should be a dot on the printing on the HM board to match.
I can't seem to find a thermocouple amp assembly doc either? I did a quick build guide for the RDTC board, which is the same circuit (mainly) with the same components, but the layout isn't exactly the same. It still may prove useful to you though.... (post #55 on the following page)
 

GSpinelli

TVWBB Member
Those are some pretty great directions Ralph. Thanks for taking the time to put them together, I may build one someday.
 

Juho A

TVWBB Member
I can't seem to find a thermocouple amp assembly doc either? I did a quick build guide for the RDTC board, which is the same circuit (mainly) with the same components, but the layout isn't exactly the same. It still may prove useful to you though.... (post #55 on the following page)

Many thanks for your help Ralph. I ordered the boards from OSH Park, and I didn't notice an option there to buy them with the SMD components already installed, perhaps that could have been possible if I knew what I was doing, or at least I could have ordered the boards with the SMD parts already installed, had the Heatermeter store been open when I was ordering stuff (I ordered everything already almost 2 months ago, it took a while for some of the parts, having stuff coming in from ebay, OSH park, Mouser and Digikey...)

Anyway, your writeup helps immensely, I hope to have a moment this evening to get started with soldering it. Luckily I have some spare SMD parts and boards, but the microchip I have only one, so maybe I'd better start with the resistors and caps... Never soldered SMD components in my life.
 

RalphTrimble

TVWBB Diamond Member
I think we have some level of confusion here...
The HM board itself has a place to build the SMD Thermocouple amp on it, the RDTC is an external version of the same TC amp that can be installed in the roto damper instead of on the HM board. This (RDTC BOARD) allows you to send the TC pit probe (and 2 food probes) through the CAT5 cable to the HM, up to about 50ft cable. The RDTC board would also allow you to add a TC pit probe to an older HM that doesn't have TC capability.
So you can build the TC pit probe amp on the HM board or build the RDTC board instead if you are interested in sending the probes through the CAT5 cable. Either way assembly is pretty much the same.
You can also buy the HM board with the SMD TC amp parts already installed, you cannot buy the RDTC board pre-built.
I found the magnifying visor to be critical to my success, and the flux helps out a bunch too. Fine tip soldering iron, steady hand, some kind of poker to hold parts in place. Buy extra caps and resistors when you order because they are really tiny and easy to lose, extras will cost you pennies but save you lots of grief when a resistor goes flying!
 

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