pwm idle contrustuction with diyautotune ms3 with pcb 3.0

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turboe36
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pwm idle contrustuction with diyautotune ms3 with pcb 3.0

Post by turboe36 »

hey guys im in the process of building my ms3 kit pcb v 3.0, right now working on the output section of the board, i need to install a pwm idle circuit for my particualar build, i dont seem to see a TIP120/121/122 transistor in my build list of parts i was sent from diy autotune, not sure if i should be using a differnt supplied transistor or if i have to order the TIP120/121/122 transistor they specify in the assembly manual.

also confused on how this transistor should be mounted and where the wiring should be routed to on the main board, the assembly manual says.


DO NOT install Q4 for use with PWM idle valves - it cannot handle the current directly for PWM idle valves. ('On/Off' type idle valves used with a relay are fine with the default Q4.)

Instead, for a PWM idle valve, use a TIP120/121/122 transistor (such as Digi-Key 497-2539-5-ND, 74¢ ea.) mounted on either the heat sink (if you have a spare spot) or the case. You should use a mica insulator (4724K-ND, 93¢) with heat sink grease as well. Run wires to the Q4 connections as shown below:

i take it i am supposed to just mount the transistor (which i may have to purchase) to the heat sink and run jumper wires to Q4 location as show in the diagram in section 62 of the assembly guide?



any help in this matter would be greatly appreciated, i felt like i was finally making some good progress on the build and now i am fairly confused.
billr
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Re: pwm idle contrustuction with diyautotune ms3 with pcb 3.

Post by billr »

"i take it i am supposed to just mount the transistor (which i may have to purchase) to the heat sink and run jumper wires to Q4 location as show in the diagram in section 62 of the assembly guide?"

Yes, I think you understand it correctly; that's the way I read the excerpt you posted. However, I have not done that mod personally.

I also think the kits only have parts for the standard assembly, you do have to purchase the TIP device separately for the mod.
turboe36
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Re: pwm idle contrustuction with diyautotune ms3 with pcb 3.

Post by turboe36 »

awesome thanks for the quick reply, can anyone else verify TIP120/121/122 transistor has to be purchased ? i really wanted to keep up the progress on this thing during the weekend :(
ashford
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Re: pwm idle contrustuction with diyautotune ms3 with pcb 3.

Post by ashford »

if you have the ms3x card why not just use its idle out?
turboe36
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Re: pwm idle contrustuction with diyautotune ms3 with pcb 3.

Post by turboe36 »

ashford, i am a complete noob and i just trying to finish my main board, should i skip the pwm idle valve setup in setup 62 and move on directly to step 63?

just trying to go step by step through the assembly guide, unsure of the things i can skip as far as the output section.
ashford
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Re: pwm idle contrustuction with diyautotune ms3 with pcb 3.

Post by ashford »

if you have the ms3x the board modification is not necessary, that is for ms1 and 2( or 3 without ms3x) the ms3x has a suitable driver on it
Six_Shooter
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Re: pwm idle contrustuction with diyautotune ms3 with pcb 3.

Post by Six_Shooter »

ashford wrote:if you have the ms3x card why not just use its idle out?

I did not read anywhere that he has the MS3X card.

Even if he does, he can still install the modified circuit and run it from the main board. This could have the advantage of being able to revert to a base setup if there was a problem with the MS3X card at some point. (an adapter harness would be needed to between the base db37 connector and the dual db37 connectors of the MS3X harness for easy plug and play switching.
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