electronics experts needed.

[kmaysob]

i am currently working on cc amp and have found 3 of the 4 transitors to be bad. i plan on replacing them but i need to know what motorola's part numbers cross to nte's. the motorola's are bd438 and bd437. any info would be greatly appreciated. btw if this works i will share it with all of you and put it in the diy section. thank you

[mplafleur]

Bd437 -> Nte184
Bd438 -> Nte185

[kmaysob]

thank you. they are quite expensive. almost $4 each and i need 4

[mplafleur]

$2.75 each at http://hobbytron.com

[bgkast]

Not to hijack this thread, but I need an electronics expert opinion too. I am trying to make a water sensing alarm for my veg oil filter. Here is a diagram that I drew up. What do you think? The water that collects in the filter will act as a switch. It has a resistance of about 20 K ohm. Will I still need R1 or will the resistance from the fluid be good enough? Thanks

[Tirebiter]

Originally Posted by bgkast

Not to hijack this thread, but I need an electronics expert opinion too. I am trying to make a water sensing alarm for my veg oil filter. Here is a diagram that I drew up. What do you think? The water that collects in the filter will act as a switch. It has a resistance of about 20 K ohm. Will I still need R1 or will the resistance from the fluid be good enough? Thanks

Skip the sensor and put in a water block fuel filter like the Goldenrod. With that you won't need a sensor. Dewatering your WVO is the biggest step in the right direction. The water block filter has a clear bowl so you see any water that it has blocked sitting on the bottom.

[bgkast]

This filter has a clear bowl to collect water too. I want to have a warning if my coolant/oil heat exchanger, in-tank heating coil, or Hose in hose springs a leak before a the filter fills with coolant and sends it to my Injection pump.

[Hit Man X]

Mmm, yes. I need to figure out the CC system on the SDL, I've tried two seperate amps to no avail. I figure it's the servo under the hood.

[Angel]

Originally Posted by kmaysob

i am currently working on cc amp and have found 3 of the 4 transitors to be bad. i plan on replacing them but i need to know what motorola's part numbers cross to nte's. the motorola's are bd438 and bd437. any info would be greatly appreciated. btw if this works i will share it with all of you and put it in the diy section. thank you

How did you test the transistors ? did you have to unsolder them from the board totally ?

-John

[kmaysob]

Originally Posted by Angel

How did you test the transistors ? did you have to unsolder them from the board totally ?

-John

i tested them with a multimeter. i used the diode function. no i didnt unsolder them. you do have to find out what pin is what

[trontek]

Originally Posted by Angel

How did you test the transistors ? did you have to unsolder them from the board totally ?

-John

Need to know what they are tied to....

[ConnClark]

Originally Posted by bgkast

Not to hijack this thread, but I need an electronics expert opinion too. I am trying to make a water sensing alarm for my veg oil filter. Here is a diagram that I drew up. What do you think? The water that collects in the filter will act as a switch. It has a resistance of about 20 K ohm. Will I still need R1 or will the resistance from the fluid be good enough? Thanks

Water is an insulator until it has certain contaminants. Whether any of these contaminants exist in the water that will get into your fuel system I don't know. I would leave R1 in the circuit but set it to a value that will push the transistor close to its limits(maximum base current) when directly grounded. Since your concerned about coolant I would suggest that you test it by adding a few drops of your radiator fluid and see if the alarm sounds.

[bgkast]

The coolant seems to provide about 20 K ohms of resistance. I'll try to rig this thing up and test it with a bowl of coolant later today. Is the maximum base current of a transistor published on the package?

[ConnClark]

The manufacturer of the transitor should have a data sheet on the internet someplace that has all the values for the different characteristics of the transistor.

[kmaysob]

Originally Posted by ConnClark

The manufacturer of the transitor should have a data sheet on the internet someplace that has all the values for the different characteristics of the transistor.

correct, they are motorola transitors. i have the new nte's and my dad is helping me. (hes the expert and the one who showed me how to test them). hopefully they are all that is wrong with it.