Ford Power Stroke Nation banner

1 - 20 of 31 Posts

·
Registered
Joined
·
125 Posts
Discussion Starter #1
Doing my IDM mod tonight and was wondering do i need to clean all the sealant off around the casing or can i just clean it up some and put some new RTV on when done? What kind of RTV do i need? Do i need to take the board out of the casing too or leave it in their to do it?

Also how did you guys take your old resistor out?? Thats the only thing im afraid to do...

Thanks!
 

·
Terminator Nation
Joined
·
5,119 Posts
I used a knife blade to clean off the residual RTV from the box along with a small wire toothbrush. The cleaner it is, the easier it is to reseal the box. I used engine oil resistant RTV since I have a lot of it around from working on the truck. The circuit board remains in the box. I used a 40 watt chisel point soldering iron to remove the original resistor. Do not pry on the resistor, you may damage the circuit board foil if you do. If you use a replacement resistor with wire leads then use a daub of RTV to support the resistor against vibration, the original type resistor is self supporting.
 

·
Registered
Joined
·
125 Posts
Discussion Starter #3
Well im pretty sure im screwed... The resistor is not sticking and i think im just melting the board. :( Any ideas??
 

·
I know nothing...
Joined
·
6,115 Posts
Well im pretty sure im screwed... The resistor is not sticking and i think im just melting the board. :(
The contact patches under the resister are small. get good lighting, if you think you botched this, pull it out clean the area carefully and put some solder down B4 the leads. This will give them something to hold to. The circut board is covered in a thin layer of gel, that might be what your melting. Any pics?

It's suposed to look like this.





You can see where I melted the blue box next to the Res, that was from screwing up. Don't lose hope now!
 

·
Registered
Joined
·
125 Posts
Discussion Starter #5
Im getting some pics now.. This sux cause i need my truck.
 

·
Registered
Joined
·
125 Posts
Discussion Starter #6


 

·
I know nothing...
Joined
·
6,115 Posts
Nothing to lose now! clean it as much as you dare, and get some solder down on the contacts. Then heat the leads into it.

It looks like you're using acid core???
And are you using a pen tip iron???
 

·
I know nothing...
Joined
·
6,115 Posts
If you look close in this pic you'll see some of the same "goose 5hit" as in yours. Be patient and steady. The worst that can happen now is you get a new IDM... might as well try to save this one.

 

·
Registered
Joined
·
125 Posts
Discussion Starter #9
I have a pin tip iron and i have two different kinds of solder. SN60/PB40 kind and SN96.5/AG3.5
 

·
I know nothing...
Joined
·
6,115 Posts
I used lead free silver 21 gauge 4900-35G.

There seems to be a lot of BB's dancing around in there. You may have to start over w/dif solder.
 

·
Registered
Joined
·
125 Posts
Discussion Starter #11
My dads telling me that my iron may be too hot?? its a 45watt
 

·
Registered
Joined
·
125 Posts
Discussion Starter #12
well i got solid lead and solid silver which one should i use?
 

·
Registered
Joined
·
125 Posts
Discussion Starter #14

·
I know nothing...
Joined
·
6,115 Posts
Is it thin? mine is very small so as not to shed and melts easily.

Take a break, get a ride for tomorrow and go to an ele store that sells solder for small ele. get a smaller iron and start over.
 

·
Registered
Joined
·
797 Posts
Silver has a higher melting point, why use silver?? It's also brittle. Silver offers NO advantages for electronic work of this type.

IMHO--Use a regular lead-tin electronic solder, that's what the rest of the board used. It's easier to work with and will do fine. Yes use small solder.

45 watts could work fine IF soldered quickly and correctly but a 30 would be better IMO. I actually prefer a hotter iron over a colder iron, I've found sometimes a 20 watter can't deliver enough heat, so it winds up sitting against the component longer...which can destroy the component being soldered. 12 watts IMO would be way too small.

Here at home I use an adjustable soldering station, and I solder a lot since I'm heavy into stereo equipment and music gear repair. I usually keep the heat turned all the way up for desoldering braid use, but back it down to a setting that equals about 30 watts for soldering stuff together. I set the tip to the junction, then I move the solder so the solder touches the junction (but not the soldering iron tip), if the iron's hot it'll only take a couple seconds or so for the solder to wick into the junction. Immediately pull the tip off and you're done. Let it cool naturally without moving or jiggling anything. DON'T cool the solder down with spit or blowing on it--that can induce cold solder joints and cracking.
 

·
I know nothing...
Joined
·
6,115 Posts
Silver has a higher melting point, why use silver?? It's also brittle. Silver offers NO advantages for electronic work of this type.
For higher conductivity, less resistance, faster travel. Isn't that why we do the mod?
 

·
Registered
Joined
·
797 Posts
The conductivity difference is quite insignificant, there won't be any measurable resistance difference nor any difference in response ("travel"). Again, silver offers no advantages here, but it IS harder to work with.
 

·
I know nothing...
Joined
·
6,115 Posts
The conductivity difference is quite insignificant, there won't be any measurable resistance difference nor any difference in response ("travel"). Again, silver offers no advantages here, but it IS harder to work with.
If you say so boss, do you have anything to offer this kid for help or you just gonna keep telling me I'm an idiot?
 

·
Registered
Joined
·
797 Posts
First, I gave him some good soldering suggestions, did you read those? I also am telling him just to get regular lead-tin solder and forget the silver stuff. This is also sound advice, better than your silver solder BS.

Look, do you even know how the IDM or similar electronics circuits operate?

The power to your injectors isn't going directly through this resistor. The resistor sets the gain on the power output transistors. Read up on transistor operation if you don't know how that's done. The difference between silver solder and regular tin-lead would be milliohms or maybe even micro ohms--that's in series with a resistor thats already 75,000 ohms plus or minus 1%!!! Who cares if its 75,000.0000 or 75,000.0001 ohms

Furthermore, the silver solder melts at a higher melting point. This is a disadvantage here. The IDM board uses surface-mount components for smaller size and automatic manufacturing techinques. The resistor in question is soldered to a tiny little copper pad on a tiny little circuit trace. It's not made to be replaced. Yet here we are, removing the resistor and soldering a through-hole type resistor to that little pad. It would be very very easy to "lift" that pad and then be screwed. Regular tin-lead solder is easier to apply and just as effective for this circuit.
 
1 - 20 of 31 Posts
Top