how to measure collector volt - help RM

[LightSoundGeometry]

 I never can get high volts on anything ..wonder what I am doing wrong. Is there a specific way to measure the collector volts? when i turn it on it clobbers my amp and sounds amazing but it is nowhere near 6-7 volts..more like .5 - do I have to keep changing out resistors until it give the C leg 7 volts?

its the small bear RM - I am using a .0056mf instead of a 47n in C1

[duck_arse]

is there a wire we can't see that connects 0V from the upper blue BB bus to the lower BB bus?

[LightSoundGeometry]

yes, I have jumpers +/-  so i can run power down both rails of the BB

[duck_arse]

can you measure all three pins on the wire links connecting to the transistor, and post volts? it may be your probe is shorting on the transistor case.

[LightSoundGeometry]

yes, give me a min

its weird..i cannot see any errors ..i been staring at this for days ..sounds amazing though ..maybe my DMM is broken ...

[LightSoundGeometry]

better overview of whole breadboard to show jumpers or anything else out of ordinary








Q1 - C .598v

b - 17.8mv

e - .471v








isn't C supposed to be much higher than E ? and if so by how much

[Cozybuilder]

You should have a pot between the collector and V+ using the outer pins, and connect the output cap to the wiper. Try 10K for starters, and adjust voltage on the collector by adding a bias pot (if necessary). Might save a speaker. Plus, you can take your measurement at any point that connects directly with the transistor C.

[LightSoundGeometry]

You should have a pot between the collector and V+ using the outer pins, and connect the output cap to the wiper. Try 10K for starters, and adjust voltage on the collector by adding a bias pot (if necessary). Might save a speaker. Plus, you can take your measurement at any point that connects directly with the transistor C.

so 10k pot, lug 3 to V+ , out to bypass switch from wiper and then lug 1 to Collector?  cool, I was messing around taking measurements everywhere lol.

what two point would I connect a trim pot? just inline with the pot and outs as well ?

i will keep on keepin on ..one day I wll get it lol

* i tested continuity , thats what the led is there for to make sure power is going down each bus rail to eliminate that part of it

[Cozybuilder]

Measure for continuity on your bottom ground rail- these boards sometimes (usually) require jumpers.

[Cozybuilder]

Like this. Start out by adjusting the voltage to about 5 (10K trimmer), and adjust until it sounds right with the trimmer.

[LightSoundGeometry]

heck yeah, got me something to mess around with. soon as I get results back I will post. most likely will be later tonight ! ty!

[Cozybuilder]

2 things- the base V should be about 1.1 V, assuming 9V for V+, and 68K for Rb (9V x Rb/[Rb + 470K]). Your measured value is extremely low, so this indicates that either the V+ is wrong, the Rb is wrong, or the ground strip is not connected at Rb. My guess is its the ground strip since your Emitter voltage is about right.

The other thing is your breadboarding skills have improved substantially in the past couple of months.

[LightSoundGeometry]

2 things- the base V should be about 1.1 V, assuming 9V for V+, and 68K for Rb (9V x Rb/[Rb + 470K]). Your measured value is extremely low, so this indicates that either the V+ is wrong, the Rb is wrong, or the ground strip is not connected at Rb. My guess is its the ground strip since your Emitter voltage is about right.

The other thing is your breadboarding skills have improved substantially in the past couple of months.

its supposed to be 47K and 3.3

I was looking at the wrong piece of paper ...oh my lol

9 x 47 / 517

.82 at Base looks like it should be. Small bear give you the Rb and Re ...im a dummy lol

I have to run errands but will re do this tonight and post results !

I have an undrilled bb size box, I may attempt my first P2P with this one...I hve copper heat sink clips to protect the tranny and I think My solder is good enough especially since I bought the wp30 ..the tip is still like new lool!

[LightSoundGeometry]

when looking at a resistor symbol on a schematic, which way is the lug pin out shown/represented on the schematic symbol? pot facing up from left to right 1,2,3 or bottom up 3,2,1 left to right?

I have a 10k trimmer - shows on the tester 4 & 6 approx - so will I treat a trimmer just like a pot pinout ? I did some googling and really couldn't find anything helpful ..will try to do some more searching and reading but thought I would ask.


I found a few diagrams

http://www.imagekb.com/10k-potentiometer-pins

http://i.stack.imgur.com/ZDth6.png

http://www.co-bw.com/Images_DIY/fig4_009.gif



lolol..i got a lot of how to trim your cannabis plants ..I guess with the key word search engine brought up a few extra websites for me to look at searching trim pots 


I reckon i will start by trying to turn an LED up and down with a current to see what this is all about !

got the LED to spin CW and CCW lol !! nice


set between 4-7 you say ..well 6v smile at the camera ..I DID IT FINALLY !! WOOOOOT

[Cozybuilder]

A trimmer is like any other pot, 2 ends and a wiper. All you need to do is figure which is the wiper- connect your ohm meter to any 2 pins and measure the resistance- and turn the screw (no change? these are the ends). The pins are usually arranged in a staggered line or V, and the one in the middle is normally the wiper. Clockwise turns should lessen the resistance between wiper and an end- that end is #3, so draw your diagram of the trimmer and label it for future reference.

When connecting the trimmer, either wire the wiper to an end and use both ends in the circuit, or just use the wiper and one end and leave the other end disconnected. Just think of it as a variable resistor.

It looks like you connected a wiper and end between power and the collector, and took your output from the collector with the cap and through a standard volume pot arrangement. Nothing wrong with that. What you should do now is test this circuit with your guitar, and adjust the trimmer to where it sounds best. Then measure the voltage- that will be somewhere between 4 and 7. You can measure the resistance of the trimmer and replace it with a fixed R, or a pot and a resistor, or just leave the trimmer in place.

[duck_arse]

usually, those 10/15 turn trimms will have a little picture of the innards etched in the body. you'll have to look close, it should have the pin references. and less parts will be smoke emitters if you have a low value fixed (1k in this case?) in series with the pot and supply. you might insert the pot in the 0R setting. Q) where would you be then?

and you photography excercise for today: can you show us the meter as you read the value of the topmost resistor in this pic, the light brown one with the scortched middle? (just for my curiousity.)



A) wafting.

[LightSoundGeometry]

A trimmer is like any other pot, 2 ends and a wiper. All you need to do is figure which is the wiper- connect your ohm meter to any 2 pins and measure the resistance- and turn the screw (no change? these are the ends). The pins are usually arranged in a staggered line or V, and the one in the middle is normally the wiper. Clockwise turns should lessen the resistance between wiper and an end- that end is #3, so draw your diagram of the trimmer and label it for future reference.

When connecting the trimmer, either wire the wiper to an end and use both ends in the circuit, or just use the wiper and one end and leave the other end disconnected. Just think of it as a variable resistor.

It looks like you connected a wiper and end between power and the collector, and took your output from the collector with the cap and through a standard volume pot arrangement. Nothing wrong with that. What you should do now is test this circuit with your guitar, and adjust the trimmer to where it sounds best. Then measure the voltage- that will be somewhere between 4 and 7. You can measure the resistance of the trimmer and replace it with a fixed R, or a pot and a resistor, or just leave the trimmer in place.

i was confused about the .22mf coming off the wiper..is there another. or easier, way to run from the wiper of the rotary to the output bypass wire ?

[LightSoundGeometry]

usually, those 10/15 turn trimms will have a little picture of the innards etched in the body. you'll have to look close, it should have the pin references. and less parts will be smoke emitters if you have a low value fixed (1k in this case?) in series with the pot and supply. you might insert the pot in the 0R setting. Q) where would you be then?

and you photography excercise for today: can you show us the meter as you read the value of the topmost resistor in this pic, the light brown one with the scortched middle? (just for my curiousity.)



A) wafting.

ducky, thats a Dale RN65C1002F 10k 1% Mil resistor , its not burnt lol

it read ≈ 9v ..I have to go back and set it up but I think it was either giving me straight 9v or the .11MA . gimmie some time on that but I will.

I am going to try my first p2p ..I wish i wouldn't of cut my BB tranny legs so short now, it will have to be used in a pcb layout probably or just relegated to a prototype bb tranny

[Cozybuilder]

i was confused about the .22mf coming off the wiper..is there another. or easier, way to run from the wiper of the rotary to the output bypass wire ?

Maybe its easier to think of the pot as 2 resistors, R1 and R2, and the wiper as a connection between the two. Their value varies depending on the wiper position, but they add up to whatever the pot value is, like this:



The unlabeled cap above is the 0.22uF output cap, and is connected to the footswitch Circuit Out pin.

[LightSoundGeometry]

i was confused about the .22mf coming off the wiper..is there another. or easier, way to run from the wiper of the rotary to the output bypass wire ?

Maybe its easier to think of the pot as 2 resistors, R1 and R2, and the wiper as a connection between the two. Their value varies depending on the wiper position, but they add up to whatever the pot value is, like this:



The unlabeled cap above is the 0.22uF output cap, and is connected to the footswitch Circuit Out pin.

Cozy, you are a genius   my pot was measuring 4k and 6k for the ∑10k

"You should have a pot between the collector and V+ using the outer pins, and connect the output cap to the wiper." - my reading comprehension is horrible , why I hate tests and love notes!