saturated's all encompassing inclusive and exclusive bin thread

[g1]

The 2 lugs on the back of the pot are a switch.  If it is measuring like that it must be bad.
You can see it (switch) was wired in series with the fuse in your other thread here:
https://www.ssguitar.com/index.php?msg=41327

[Tassieviking]

Did you put a knob on the shaft before you tried it ?
Some of the older ones might need a bit more force to turn the last bit so it activates the switch.

[saturated]

thanks guys for the help
yes sir i am stressing my fingers and it is clicking on and off
I am going to put this thing back together bypassing that pot
I just need a new kbpo6 ( edit: 2KBPO6 )which is obsolete..but out there...the one i took out tested good i just dont want to solder it back in. 

so concerning this metronome..nothing makes sense...it had what i presume was a dead short...yet the on off switch is open both ways. idk

im wondering now if one of those terminals was making contact with the metal case...hard to tell now that i have gone in and messed up the original conditions.
a good lesson to watch for that kind of stuff next time.
anyhow I dont want to make a habit of disassembling everything and throwing my hands up so that is my plan: solder in replacement bridge rectifier..bypass on off vol switched pot and see if i can get some life out of it.

not to complicate things but another issue..the big dial potentiometer to adjust speed...has no stops...just turns infinitely in either direction.

ok time to get my meter out and take a look

  

[saturated]

well that was informative
it just starts over and over if you keep spinning

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amazing

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but...alas the task of reinserting this is not easy...connected to each terminal are very fine jumpers....

from what i remember i didnt sever them they basically disconnected just by breathing on them

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ugghhh

 

[Tassieviking]

That potentiometer is meant to rotate fully around, it is made that way.
That one has no inbuilt stops on the shaft.

[saturated]

ok this evening I wanted to check some voltages on my oscilloscope now that thanks to Mr Mick I have a schematic I can actually read.

I also learned that wires have two ends.  meaning all the while I knew to stay away from the wires on the end of the CRT.
I should have known that the ends of those wires are in the top middle of the following photo.

particularly the larger diameter red ones

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I only became aware of this as happily trudging along taking measurements suddenly saw a large negative number.

I was somewhat pleased yet perplexed that the numbers (to me) looked pretty good...? as if they were reasonably close to those on the schematic.
edit: also the anode of d408 measures 21.8v

so moving on to the board with the ICs I quickly noticed a trend...that is there was no voltage to be had..

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I was a bit uneasy because a couple days ago I was able to get low voltage on those IC pin 14s...now nothing. 

now granted IC 303 is vacant but idk...

Im glad i didnt start ripping out capacitors and stuff.

 

[saturated]

one thing I need to work on is checking resistors.  I kinda dont want to because I have to desolder one leg and lift it.

 

[saturated]

pretty funny what i just learned

I was making circuits on breadboard and trying to measure voltage drops with my oscilloscope.

I was getting frustrated...crazy whacked numbers...trying to make sense of it..which I could not.

turns out I thought a scope was like a multimeter 

just connect it across the component in question..just like a multimeter...right?

NO 



(of course you already know this)

the ground terminal on oscilloscope probe

drumroll......

spoiler....

is actually a ground.

[Tassieviking]

I also learned that wires have two ends.  meaning all the while I knew to stay away from the wires on the end of the CRT.
I should have known that the ends of those wires are in the top middle of the following photo.

You will quickly learn to be careful if you touch those "hot" wires, but don't worry, it only hurts till you pass out.
You just need to worry about waking up after you pass out, it's not guaranteed.

[nosaj]

If you need a probe to measure the HOT wires i have a 30kv probe you can have for shipping.
nosaj

[saturated]

man this forum is the best and you guys can take all the credit

i did some deep digging at my friends junk store and found some nos ic

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i havent looked them up yet

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there is a prescription bottle full of used transistors from 1970

 

[saturated]

if anybody is looking for anything let me know it could be in here

[saturated]

and the first item pulled from the grab bag....
I thought these were some kind of lights or something

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turns out they are ultrasonic sensors

I am going to read more about them...like if they detect people or if it has to be metal
 

kinda cool

might be fun to play around with

[saturated]

and some more laid out and identified...somewhat

spoiler...all the green boxes are the same thing 2N3391A

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probably pretty common stuff

some big diodes 

i was curious about a couple items...the ecg3036 has like a lightbulb on top of it...

and the rca sk3006 has four legs

i know...google is my friend

 

[Tassieviking]

Light bulb on top sounds like a photo transistor of some sort.
The 4 lead SK3006 is a Germanium transistor that has an extra leg for the metal cap on top as far as I know, and the SK3004 is also a Germanium transistor.
Some Germanium transistors are becoming expensive since they are no longer available and are very coveted for Fuzz pedals.

You should test all the Germaniums individually and record the findings.
https://www.radiomuseum.org/tubes/tube_sk3006.html

Datasheet is too big to upload here so here is the link:
http://bitsavers.trailing-edge.com/components/rca/SPG-202Z_RCA_SK_Series_Replacement_Guide_1981.pdf

Look at page 26 for the SK3004 and SK3006