Babelfish M25, SissySIT - general building tips and tricks

Beautiful work as always Juntuin!

Thank you very much! 🙂

well , be sure what's alive , what's not - before powering up

if you're monitoring across R in CRC (cap bank) , initial current jerk is normal (filling that second C) , and it's short ..... long enough to scare you for a moment

🙂

I don't understand those huge reading differences across resistors, what could cause those? Well, I'll do some work and try it again.
 
Correction; Only R19 is now showing strange readings.. 31,2k on working amp, 100ohm on non-functional amp. And yes, they are same size resistors, took them off and measured to be sure 😀

Edit; and Q4 all legs shows shorted in multimeter on non-functional amp. Just to be clear, IQ was set to zero at first powering attempt. Took Q4 off and it's definitely broken. Now R19 makes some sense. Can I try 9240 instead?
 
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well , wasn't behind you when you powered it , so I really can't say what was wrong

sole thing I can say-that I never stumbled on bad brand new IRFP mosfet , never .....

yes, you can use 9240 instead , and you most probably will not hear any sound difference between 9240 and 9140
 
well , wasn't behind you when you powered it , so I really can't say what was wrong

sole thing I can say-that I never stumbled on bad brand new IRFP mosfet , never .....

yes, you can use 9240 instead , and you most probably will not hear any sound difference between 9240 and 9140

I didn't meant to be rude, just tired 😀 two identical channels, other one works and other won't work.

Something chanced along 9240. Now it stays stable couple on mV's about 10-15sec, then starts to climb slowly, but with increasing speed as volts go up.
 
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is it oriented OK ?

regarding part quality , I took care to buy so called "double gauge" , which means no nowadays thin-back regs ; and I know these are imported from reputable vendor ( range of Digikey, Mouser , Conrad , TME)

just in case , 7805 with name looking at you , pins down ; left pin is IN , mid pin is GND , right pin is OUT
 
It was oriented as silkscreen marked, so pretty sure yes 🙂 is it possible that I have broke it myself somehow? I haven't actually never got my hands on new unused broken component since I also buy only from Mouser and Digikey. This time I hope that it is the case, voltage regs are those rare parts that I can buy locally!

So I checked it like 10 times visually and DMM, there was about 25v input and 0v output, so soldered it off and getting new regulator at monday.
 
well , I didn't made them by my self , so I can't vouch for zillion % for anything

but , as most parts which are in kit and as for regular things I'm buying for everyday's work , I'm buying same things from few local vendors at least last 20 years

never had faulty 78xx or 79xx , but there is always first time for everything 🙁

though , all you need to ruin it is one slip with probe or tweezers, sometimes even unnoticed

can't tell that I didn't made exactly that , more than once

just recently , while assembling previous SissySIT , I killed one BD critter ....
 
just checked few things on web - these are certainly made by ST Electronics , so I resume reputable company

anyway , that's irrelevant now - what I meant to wrote is - while troubleshooting , it's probably wise to solder/mount 3A15sloblo fuses in both rails ; once when you are on safe ground , remove them out
 
well , everything.... hoping that you'll soon rolling happy tears , like pretty much everyone who made it

(or got made by Mighty Moi :clown: )

edit: to recapitulate .... I am here just for the money , but always happy when Greedy Boy is happy

:rofl:
 
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