Need Help w/ Resistor Readings

Ok, you got your soldering iron and nothing is going to hold you back, but you have no clue where to start or what to build. There were others before you with the same questions... read them first.
Post Reply
User avatar
whitebread47
Information
Posts: 11
Joined: 25 Sep 2011, 13:43
my favorite amplifier: Vox AC15C1
Completed builds: Whoa! Put me on the spot there...err....um...I think I hear my mom calling.
Location: Louisiana, US
Contact:
Contact whitebread47

Post by whitebread47 »

I am building my first project, a Fuzz Face variant. I have soldered the resistors in only so far and have been checking resistance of each one as I go. The R1 and R2 read within the tolerance on my DMM, but when I got to R3 things went awry somehow.

I should mention that I had just finished a Red Bull, so my hands were shakier than normal and I should have waited for that to subside. The problem began when I accidentally soldered one of the holes for R3. I got the resistor in there and soldered, but instead of reading near the 220 ohms it read about 134 or so even after desoldering and soldering it again. I then went back through the first two. R2, which read at a perfect 33k at first, now reads about 11k. R2 is right next to R3 where the problem began. :slap:

I've resoldered R2 and the results were the same. I then soldered in R4 to see if maybe I burned the board to the point that none of the resistors would read correctly.

My questions are: Can one "ruin" a board if the iron accidentally (from shaky hands) touches a spot that is not designated for soldering joints? If so, would resistors even show a value on a DMM if that were the case? Also, could the excessive heat from soldering the resistors in a few times have tampered with the resistance?

Unfortunately, I only ordered one of each resistor I needed so I can't try replacing them at the moment. So now I'm trying to figure out if I need to order a new PCB.
Top
User avatar
whitebread47
Information
Posts: 11
Joined: 25 Sep 2011, 13:43
my favorite amplifier: Vox AC15C1
Completed builds: Whoa! Put me on the spot there...err....um...I think I hear my mom calling.
Location: Louisiana, US
Contact:
Contact whitebread47

Post by whitebread47 »

While researching possible issues, I stumbled upon this: "You can only test a resistor before it has been soldered/inserted into a circuit. If you measure it in the circuit you will also be measuring everything connected to it. In some instances this is OK but I would say that in the vast majority it is not. If you try, you will get incorrect readings and that's worse than no reading at all."

Could this mean that all is well? How can I check, like is there any resistance math I can do to verify that I'm hitting close to the right amount?

My apologies for so many questions. I am extremely driven to get this right and figured I should present any questions that come to mind in pursuit of know-how. :mrgreen:
Top
User avatar
DaveKerr
Solder Soldier
Information
Posts: 197
Joined: 14 Mar 2010, 05:00
my favorite amplifier: Ampeg M-15
Dynacord Preference 500
Completed builds: Fuzz Face (2)
Tonebender MKII (3)
ROG Tri-Vibe
PAiA Ring Mod kit
Ring Mod based on Tim E schematic (2)
Rangemaster
CNO
ROG Splitter-Blender
Clari (Not) cubed deluxe
Location: Boston MA area
Has thanked: 53 times
Been thanked: 10 times

Post by DaveKerr »

I think you answered your own question - plow ahead and start making some noise.
... multiple LFO waveforms (saw up, saw down, triangle, square); a more flexible envelope with attack/release controls as well as inverted envelope. I am afraid it will have more knobs than the TGP annual convention - frequencycentral
Top
Post Reply

Return to “Basic Knowledge”