well guys I submit my latest quandary 

I wanted to work on that metronome from a while back...I remember getting frustrated trying to ohm test the switched potentiometer.

I could swear i even wrote it down...the black mains? were soldered to the rear terminals...

when I connect my multimeter I get nothing from the rear terminals except "1" which i presume means "open"
turning on and off, all the way in either direction...no change
now when I test the other three terminals I get min and max (100k ohm) but the switch doesnt do anything

I have googled the heck out of this and retested and rechecked
it is a clarostat...I saw an ebay pic of one that had a wire from one of the three going to one of the rear

anyhow does anybody know what the terminals on the back are for ?

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im guessing they are supposed to be earth or common idk

also there are no markings on the back except a funny looking dogbone shaped symbol....besides manufacturers info

thanks for you help sir I am enjoying becoming familar with some of these terms like 14 dual inline package

I shopped around a bit and found some of the components as well as encountering some more terminology...like inserting "LS" in the numerical designation.
apart from learning what it stands for "low power schottkey?" no i dont know what it means

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meanwhile I think I need to go back and see if the 1 pins on the chips on that board are getting voltage..

 

edit...pin 14

edit 2...just plugged it in and checked those pin 14 voltages
IC 301 looked pretty good but the other ones only showed about 1.5v...
I was surprised to see anything...that board is pretty rough
who knows

I am really enjoying this set up

very much so

but apparently this Crate Amp was neglected and not played enough and in need of some love

because this slide switch has been cutting in and out and off and on...but getting better with some exercise

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ok im kinda finished

man the mosquitos are unreal
i had on shorts and sandals and got eaten up all day constantly

i got it put in my room

its pretty ugly

surely there will be some modifications

and the roof is not on the top book shelf yet

i have mixed feelings but its ready to rock....

Peavey...Crate...Peavey....and last but not least...Ibanez

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ok back at it...gonna build a similar overhead shelf network for my three amps and guitar books etc

first had to go to a construction site and scrounge up some wood

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then spent a few hours getting nails out

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lots of nails

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and finished wood with no nails

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looking forward to having my amps organized and ready...two Peaveys and a Crate

 

I just dug into my box of junk to take a look at what ICs I had to see if I could get lucky

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from left to right...

RS 7400N seven legs

DM7490AN seven legs

S7409 seven legs

a bunch of HCF4040BE eight legs

and a bunch of seven legged sockets....

time to start ordering some stuff

 

thanks for helping and taking the time to post and attach that content

you rock 


and you are right...the data sheets are very interesting....and extremely intimidating 

I am relieved..i think..that they are plug and play

I will try to track them down

a brief search last night showed that two are plentiful and cheap..like 36 cents...another is available for like six dollars but the other one is only available from a place in Canada

thanks again!!  i have some pics like that but the ones you posted above have better resolution...mine have a dark haze and are tough to read..
I have pretty much dismissed desktop computers and monitors as obsolete and dont have one anymore in my work space but i was seriously considering getting one out of storage and bringing it back in so i can actually see and read stuff instead of squinting and zooming images on my phone.

anyway i wanted to ask about this diagram...i had looked at it a few days ago because i wanted to take voltage readings on the legs of the chips.. but i couldnt make sense of it and just scratched my head
especially how 4.8v gets divided into 14v....
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but then i saw this one

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and was further lost...i have a lot to learn obviously

then they had separate little boolean bullet symbols for IC 301....so I need to do some homework on this stuff

anyway have a great week end

 

thanks guys

it is SO-4540

which (I think) means preassembled...

 

ok i wanted to fix my heathkit oscilloscope but alas i feel its journey has possibly reached its end

I kept probing carefully around the low voltage ps stuff and got decent voltages...kinda started to look at the sweep trigger board and four ICs located there

tried to get some voltages without much luck...

decided to unplug IC303 and as gentle as i could be to my horror when it came out some of the pins broke off or disintegrated...

 
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i guess i could buy new sockets and new ICs....idk

i dont even know what they are....yes looks like some water/humidity damage there

i live in the swamp and this was in a building for years with no a/c and leaky roof

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so TLDR if i could obtain the sockets and chips at a reasonable price that would be a good project for me


edit..apparently said component is motorola 443-4

some more groundbreaking earth shattering cutting edge work today 

wanted to connect signal generator to amp

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that was fun
but too easy and predictable

better yet would be to have the amp opened up and try to find the signal by probing around on some components

i made a video with outer limits sound effects

 

i tried it out for a while but didnt get too far

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amazingly all 4 lights at the bottom work

its def responding...if i turn the second digit to zero the meter deflects

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and back to one which i presume is ten....it goes back

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oh well that was fun

time to catch the rest of some football

so i wired up the replacement power cord..which wasnt looking so great either 
no matter how far back i peeled back the outside sheathing the insulation on the interior wires was crumbling
but it appeared the white insulation was more robust...so i went with it

also the wierd lookin fuse was blown
i do not have anything that remotely resembles this

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so based on the markings i scared up a plain ol 1/4 amp fuse and stuck it in

next up connected my UDBT (ugly dbt)

powered up...turned it on and all was eerily quiet

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I thought well something is open somewhere...this is too good to be true...was fixing to disconnect everything and to my astonishment saw a light on

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so i guess my next move is to input a known voltage and then try to rotate the bottom knobs until it matches up....

 

alright i wanted to test my new voltmeter

so first task was unsoldering the disintegrating power cord

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which wasnt easy

hot from transformer

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ground from fuse holder

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and green....common?

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and the disconnected carcass

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this is a lot of work but oh well i guess its good practice

gonna be all for naught if i get a new cord on there and it fails dbt
because at that point im stopping

also i am discouraged to see silver metal transistors...to me that means germanium...but idk i have no idea

 

on my to do list...need to build a curve tracer and connect to my oscilloscope

either that or find a tek 575