No sound on right channel (AKA: Apparently I must be a total newbie)

[bigfatpaulie]

It's a sacrificial pair of old HD433's - I'm okay if they blow up.

I, again, will point out that each time I am testing the continuity from a different place on the board to the other side of the component to ensure continuity (IE, testing if the actually solder joint is conducting) AND measuring the resistance.  If it isn't 0 ohms, I redo it.

However they look, I would honestly bet my right hand that the solders are all working...

So I'll ask again, is there, however small, a possibility that a transistor isn't functioning correctly? 

PS, sorry but the bad photos

[fullheadofnothing]

Could you please remove the board and photograph it in focus and without backlight?

While the board is out, you could re-install the 3K resistors and confirm that the amplifier passes signal without the large Speedball board.

Also are you checking voltages after resoldering? You have not specified how you are determining that there is no change, and the only unchanged symptom you have listed is the dead channel.

[bigfatpaulie]

I, sadly, don't have the resistors anymore.  Like an idiot, I thought this was going to a simple upgrade...

When I say 'no change' I mean the right channel is still dead.

Wish I could get an answer to my question - is it at all possible that one of the parts has failed?

[bigfatpaulie]

Could I substitute film resistors to test?

[Paul Birkeland]

I still see cold solders on those TIP50 transistors.

Are you, by chance, using lead free solder?  What kind of iron are you using?  Heat and lead will be your friends for getting a good joint.

[bigfatpaulie]

Hello,

It's a Solomon SL-10 soldering station and it is "Rosin core Solder for PC wok".  It does contain lead.

I realize that solders look a little gray, but it is the photo and reflection.  In person they are all shiny. 

Are there any other test/measures I can do?  Or should I just start buying replacement transistors?

BIG BOARD:
OA: 103.1
OB: 148.7
G: 0
B+: 196.0

SMALL BOARD:
OA: 77.7
IA: 196.6
B-A/B: 0
IB: 196.1
OB: 70.6

[Paul Birkeland]

It's not the sheen or lack thereof, those joints just need a little additional solder.

A shorted transistor will measure very low impedance between a pair of legs.  In the absence of such a measurement, the transistor in question is likely working properly.

[bigfatpaulie]

I don't mean to be rude, but this is a little frustrating...  You said cold solder joints and in the manual it says: A cold joint will usually appear as a convex blob and be dull or even crystallized in appearance."

Now you are saying it isn't enough solder, which is different.

I'm confident that 'not enough solder' isn't the issue.  See the image - I've ONLY soldered from the underside of the board which means this is solder that has flowed down.  There is A LOT of solder...  Are there any other voltage test/results I can give you?  Is there another possibly aside a bad solder joint?  Like anything, however remote, at all possible?

Please.

[Doc B.]

We all sometimes get frustrated when we are sure that we have done what has been suggested and things still don't work. I'm looking at that middle pin of the TIP50, and I have to say the first thing that comes to me is that I would reheat it until I saw that blob melt and create a fillet with the solder pad. Generally the best approach when reflowing a joint like that is to have a solder spool handy so you can add just a little bit more solder of it looks like it is necessary to get a fillet to the pad all the way around the lead. We're not trying to frustrate you, we are trying to help.

[bigfatpaulie]

That's the thing, please don't get me wrong: I really appreciate you guys trying.

But, truly, I can't help but feel after re-flowing the solder three times, then de-soldering everything, then re-soldering then re-flowing two more times - doing all that and each time I have the exact same issue...  Not to mention things like the TIP50's have been reflowed probably another 4 - 5 times and de/re-soldered additionally.

And does the shift from the right side to the left side not strike either of you are odd?  I mean, have you ever experience that, and if so was it a bad solder joint?

Also - can I use film resistors and remove the big board?  I realize they will get really hot, but I just want to see if I can get both channels working, even if for just a moment.

For your review before I reinstall the board yet again, how do these solder joints look?  Please note that I have only added solder to the bottom side of the board, everything on the top side had flowed though.

[Paul Birkeland]

Those solder joints look a lot better, let us know what voltages you get with the board in that condition.

Using a pair of film resistors in place of the large Speedball board is possible, but you'd need a pair of 3K/3W parts.  These will get insanely hot, but they shouldn't self destruct too quickly.  Anything under this power rating is going to smolder rather quickly.

[bigfatpaulie]

Thanks.  Okay, no dice.  So I desoldered the TIP50's again and re-soldered.  Again, no dice.

So I took some of the kit wire and bridged from each of the three pins to their locations on the PCB and HAZZAH!  Sound!  I don't know if the wire is helping the connection, or if there is a brake on the board or whatever, but I am getting sound now.

That said, the sound on the right side is quite a bit quieter than it is on the left...  IE, the challenges aren't balanced now.

Is there anything I can do to fix this?

[Paul Birkeland]

Post your new voltage measurements.

[bigfatpaulie]

OA: 102.3
OB: 112.5
G: 0
B+:  189.8

[Paul Birkeland]

Now test to see if the volume balance is due to the volume pot.  To do this, plug your phone into the Crack with the phone level very low and the Crack's volume pot nice and high.