Aion Theseus - KOT Clone Troubleshooting

[Matthew Sanford]

Welcome!

I might not really be the knowledge level to comment here, but I think it could be good to use an audio probe to see where it dies around IC1, that might narrow your search a bit...

[davidplaysbass]

Take IC1 out of socket and measure voltages on pins 1,2 & 3..

You should get previous VB measurement on pin 3 and nothing on pins 2 & 1..

About the IC: If you take out the chip, it won't conduct or function, so pins 1 and 2 of IC1 should have no voltage on them. The only connection to something that can provide DC current would be IC1 itself, including the second half of IC1 which would be not connected, and would be blocked by C5 even if it was connected.
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Oh oh oh oh ohhhhhh!!! I was trying to figure out how to measure voltage on the unplugged IC but you meant measure voltage to the empty socket pins!    Done and done. 1, 2, & 3 all measure as you said. Same on 1, nothing on 2 or 3.

Welcome!

I might not really be the knowledge level to comment here, but I think it could be good to use an audio probe to see where it dies around IC1, that might narrow your search a bit...

Next step in my journey may be to make or purchase an audio probe, then!

[Matthew Sanford]

You can make them, whatever wire you use goes to a cap (100n should be good) then to a Jack so you can hook it to an amp. Some build a LM386 amp specific for it, but not necessary. So an alligator clip wire from jack's shield, clip it on ground in the circuit, Jack tip -> cap -> wire and probe input on to see where it's gone.

On IC socket, pin 3 should show bias voltage but looks like you said it's 0 volts? Sounds like the issue, maybe a good bit of solder on the iron's tip first will get heat transfer for proper reflow (if that's the issue). I know I've "reflowed" insufficiently myself...

[davidplaysbass]

On IC socket, pin 3 should show bias voltage but looks like you said it's 0 volts? Sounds like the issue, maybe a good bit of solder on the iron's tip first will get heat transfer for proper reflow (if that's the issue). I know I've "reflowed" insufficiently myself...

Woops! I think I mistyped that but I just gave the boards an IPA bath and toothbrush scrub and they're drying now so I'll retest to be sure at some point tomorrow.

[Matthew Sanford]

Yea, one end in the socket side pin 3, then maybe the Vb checking resistance, 1M good... but build an audio probe, when stuck with solder/voltage issues being your focus it offers a different way to think on it. Gotta unglue your nose from it so you can back up and see it all, figuratively speaking.

[duck_arse]

geeze they are big photos. we can't complain about them.

lol yeah...sorry...?    Too many tiny pics in various other threads on other forums so I figured I'd maximize!

what's happened to the inner leg/pad of R5, especially solder side?

Hahahah I was hoping nobody would notice that. I think I stood a little too close when I clipped the lead on that one... Fortunately, there's still just enough length that it comes all the way through the hole, seems to make contact with the board, and holds solder. Is there an easy way to check to see if that's the issue short of replacing the component?

you show us big pics, we will see things. there seems to be a huge blob of solder on that leg topside, is that also the case?

to measure and check, observe the circuit dia. one leg R5 connects to C3. so find that C3 leg and measure the resistance to one leg of R5, which should show 0R, then the other leg of R5, should show 33k. then measure from C5 to pin 2 of the IC, which should show 33k, and will clear/prove the tracks and solders all the way between C3 and the IC. measure also to R2 and to R4, they shouls also show 33k [or 33k + 100k, or 33k + 27k].