R51

Forum for discussing how to install MicroSquirt(TM), choose and troubleshoot sensors, wiring, and communications for MicroSquirt (TM) and MicroSquirt Module(TM).
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Post Reply
800vtwin
Helpful Squirter
Posts: 84
Joined: Mon Feb 16, 2009 10:06 am

R51

Post by 800vtwin »

Is there a difference between using a 1k pullup on pin 4, to swapping out R51 for a 1k?
Matt Cramer
Super Squirter
Posts: 910
Joined: Sat Jul 03, 2004 11:35 am

Re: R51

Post by Matt Cramer »

Only if you also had R50 jumpered. With R50 in the way, you'd only pull the voltage on pin 4 down to 4.5 volts if you ground pin 4.
Matt Cramer at DIY Autotune
Image
800vtwin
Helpful Squirter
Posts: 84
Joined: Mon Feb 16, 2009 10:06 am

Re: R51

Post by 800vtwin »

What if i remove R51, use the top pad (towards vcc/D6) from R51 and put a 1k resistor to vr2 in side of R50? Leaving r50 intact. Or should i still short r50? Or how else could I accomplish this? I don't want to use any external resistors for a project.

Is there any downfall or issues with doing this internal mod? -Or 100% good to go? Or would it be safer just to add the 1k across the pins between the ampseal and pcb.

Externally, Pin 4 biased to 5v actually makes a cleaner signal for me than going to 12v. With this in mind, will just swapping r51 as i mentioned be the fix?

(your statement confuses me a little, as if your saying- as in production form, when pin 4 is grounded, the voltage is pulled down to 1.8v. If the resistor R51 is changed to a 1k, then the voltage will be pulled down to 4.5v. ) If this is the case, i understand the circuit a little better and you already answered my question in the first post.

So to get this straight, i can bias the input circuit to either 5v or 12v with R50 & R51 mods. And there is no downfall or risk in doing so.
Matt Cramer
Super Squirter
Posts: 910
Joined: Sat Jul 03, 2004 11:35 am

Re: R51

Post by Matt Cramer »

I meant to say that if you had swapped R51 for a 1K resistor, and made no other changes, grounding pin 4 would only pull the voltage on the input of the VR conditioner down to 4.5 volts.

If you want to add an internal pull up, why not solder a through hole resistor to the pins on the AMPSEAL itself?
Matt Cramer at DIY Autotune
Image
800vtwin
Helpful Squirter
Posts: 84
Joined: Mon Feb 16, 2009 10:06 am

Re: R51

Post by 800vtwin »

Yes, i can solder across the ampseal pins.

I was just looking at doing the mod on pcb as I have 3 version 1's that i am updating/ swapping smt diode and resistor for through hole. (D5 & R26) I figured another resistor swap on pcb was easy enough at the same time. And a little cleaner. The version 1's i have are just test units kinda and not critical. Any version 2's will be across the pins.
Post Reply