LED and voltage issues

[Viekes]

Hello there

I've just received my Crack in the mail. Spent all day working on it, mostly without issues. Passed the resistance check with no problems and both tubes light up fully. However, neither of the red LEDs light up and when I check the voltages I get:

T1: ~80 mV
T2: ~190 mV
T3: 0 V
T4: ~190 mV
T5: ~80 mV

T6: 0 V
T7: ~240 mV
T8: 0 V
T9: ~225 mV
T10: 0 V

All the values started out higher (highest being ~600 mV on T2 and T4) but dropped down to these after 15~20 seconds.

I went through all the steps again and found that I had inverted a capacitor but that didn't change the measurements. Neither did re-soldering a few of the more questionable joints.

I'm not sure what to make of this. Any help is appreciated.

 

[fullheadofnothing]

Post pictures.

 

[Viekes]

Anything specific or are these good enough?

 

[Doc B]

The black wire that runs from the nine pin socket center pin to the volume pot - resolder the end at the volume pot.
Also reflow the lower hole of T-strip terminal 3. There is a black wire connected there, that connects to the headphone jack at itse other end. Reflow the connection at the headphone jack end as well.

 

[Viekes]

After resoldering and reflowing, T1 and T5 dropped to 40~50 mV. No other voltages changed. Also, the red LED connected to A3 now lights up but it's so faint I can barely see it.

 

[Doc B]

Is T7 properly soldered? You might check at T12 to see if you have 170VDC or more. If not, the problem is somewhere in the wiring around the power transformer.

 

[Viekes]

T7 should connect properly, I've resoldered it just in case.

T12 reads the same as T2 and T4. There's a slight bulge in the cap connecting T12-T13 that I hadn't noticed, I guess it could be the issue?

 

[Paul Birkeland]

I see many solder joints that will cause the problems you're having. You need to heat the wire and the terminal by pressing the soldering iron against both at once, then flowing solder onto the iron and the joint.

 

[Viekes]

I'll be the first to admit that my skills with a soldering iron are mediocre at best. That includes spotting bad joints. As far as I can see, there are no cold joints, no loose leads, no joints that have too little solder and a few that have too much. I'm not saying there aren't any bad joints, for all I know they could all be bad.

Would you be willing to point out some of them so I can get an idea of what to look for?

 

[Doc B]

You can use experience to guess what joint might be good or bad, but you can't see if a joint is conducting properly. The most reliable way to confirm the integrity of the solder job is by reheating every joint just enough to remelt the solder, then see if it changes things. This takes about 10 minutes, a lot less time than waiting for us to guess from a photo what might be a bad joint

 

[Paul Birkeland]

The black wires coming out of 3L show too much heat applied to the wires themselves, and not enough to the terminal strip.  It looks like one of the wires on that terminal has no solder.  At terminal 20U, I can see another black wire that looks to pass through without being soldered all the way.

As Doc B. said, you can just reheat all the joints and wait for the solder to flow out.  It looks like toward the end of the build, you were starting to get the hang of it, so you'll just have to apply that experience to earlier steps in the build.