Smoking Crack w/Speedball

TontonFlingeur · 4164

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Offline TontonFlingeur

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on: December 17, 2013, 09:27:07 AM
About two weeks ago I noticed a lot of static coming across both channels.
I poked around with a chopstick, and couldn't get the crackle to diminish or increase; it just stays at roughly the same volume and frequency of occurence (random).
I also ran voltage checks, and the readings are approximately halfway where they should be.
When I flipped the plate over to start digging around, I noticed that after about 10-15 minutes under power, the two big 2229As upper left quadrant were extremely hot, to such an extent that smoke is being produced by one of them.
I can't really eyeball which cap is producing the smoke, but by touch, I'd have to say it's the 14 / 15 unit, since it's too hot to hold onto for more than 2 seconds. 12 /13 is hot, but not painfully so. Same for the 20 / 21 unit.
Any thoughts? All white bands on the big caps are facing south, meaning towards the headphone jack.
My LEDs are also all red. The LEDs on B and A are very dim when compared to the two on the upper center Speedball board - those two know it's Christmas and want Rudolph's job!
One thing I have noticed is that a lot my solder joints look like crap; a crusty, corroded yellowish color, the kind of gunk you can get on a car battery terminal, or 10 days after shore leave.
I'm planning on reflowing everything, but want to hold off until more enlightened minds chime in, since it seems I end up reflowing about every 2-3 months, so my hunch is I have a deeper issue.
Thanks, all, this forum is a godsend.
-Dave



Offline Doc B.

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Reply #1 on: December 17, 2013, 09:33:06 AM
What kind of solder did you use?

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline TontonFlingeur

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Reply #2 on: December 17, 2013, 09:59:47 AM
Hello Doc,
And damn, quite the honor!
From Do it:
40/tin, 60/lead, acid core.
Best,
-Dave



Offline Paul Birkeland

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Reply #3 on: December 17, 2013, 10:15:08 AM
Acid core, yuck!  These also tend to have conductive fluxes that bridge every adjacent contact in the entire amplifier, leading to noise, arcing, smoke, etc. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline TontonFlingeur

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Reply #4 on: December 17, 2013, 10:27:15 AM
Consider me chastised!
So, this build cannot be saved?
I could try to desolder the snot out of it, but why bother, best to start anew and afresh ....
Do you agree?
I'll trash my build.
I was hoping to make this work.

-Dave



Offline Mike B

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Reply #5 on: December 17, 2013, 12:02:27 PM
Pretty much.  That stuff shouldn't be used for copper pipe.  It's for soldering difficult metals with a torch.

Use 60 (tin), 40 (lead), rosin core for the next one.  And thin ~.030" too.

Bummer.

Far away from the bleeding edge


Offline Paul Birkeland

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Reply #6 on: December 17, 2013, 12:12:55 PM
Consider me chastised!
So, this build cannot be saved?
I could try to desolder the snot out of it, but why bother, best to start anew and afresh ....
Do you agree?
I'll trash my build.
I was hoping to make this work.

-Dave

Water is your friend, lots and lots and lots of water.

You generally want to keep water away from the power transformer, so you'll have to get a wet toothbrush and scrub, scrub, scrub!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline TontonFlingeur

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Reply #7 on: December 19, 2013, 10:32:53 AM
I'm pretty sure I'm out of luck on this one.
I tried reflowing the joints, using the rosin core solder that Mike B recommended, and swapped out the capacitors for new ones, but still hearing the static
This is really too bad, the sound was great when everything was working well.
Thanks to all for the advice and tips.
Best,
Dave



Offline Paul Birkeland

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Reply #8 on: December 19, 2013, 11:11:06 AM
I'm pretty sure I'm out of luck on this one.
I tried reflowing the joints, using the rosin core solder that Mike B recommended, and swapped out the capacitors for new ones, but still hearing the static


As I said above, the flux in your plumbers' solder has deposited a conductive residue all over the place.  This has to be cleaned off before the amplifier will work properly.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Mike B

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Reply #9 on: December 19, 2013, 11:26:02 AM
You might try this, but proceed at your own risk.  If it doesn't work, don't blame me.

Remove the transformer.

Put the chassis in the dishwasher parts side down on the bottom rack.  Use dishwasher soap and wash just like dishes.

Let dry a couple of days and power up cautiously.

We used to put every board we did thru the dishwasher after wave solder, it won't hurt the parts.  You don't want to wash the transformer though.

The acid flux will destroy every part on the plate if you don't remove it.  Really I think there is little hope as acid residue will exist in the soldered joints and will work incessantly to destroy them.  But hey, if it works you will get some listening time before you have to trash it.

Far away from the bleeding edge


Offline Paul Birkeland

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Reply #10 on: December 19, 2013, 11:47:45 AM
The dishwasher is a good recommendation (and removing the transformer is mandatory).

I'd also opt to not heat-dry the parts.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Joppa

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Reply #11 on: December 19, 2013, 01:38:21 PM
...
I'd also opt to not heat-dry the parts.
PB, you're getting cautious in your old age!  :^)

Paul Joppa


Offline Tinman

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Reply #12 on: December 20, 2013, 01:38:17 PM
Just ordered my first project.  Where is a good place to get the right solder?  and I want to buy a good solder iron, because I plan doing many more projects.

Thanks

Tyson Hagerman
Just bought some crack!  Can not wait to try it for the first time.


Offline Grainger49

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Reply #13 on: December 20, 2013, 02:39:28 PM
Many will suggest the Tenma irons.  I'll suggest a nice Weller.  I often post when there is a Weller Sale at MCM Electronics. 
« Last Edit: April 21, 2014, 12:11:14 AM by Grainger49 »



Offline Tinman

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Reply #14 on: December 20, 2013, 03:29:15 PM
Thank you, I will check both of them out.  I think my local serviceman uses weller.  Now that I know what iron to get, what kind of solder do I get?  I saw the earlier post in this thread, but I thought uber hifi solder had stardust and 90% silver in it..... ;D  just messin, but for real I thought solder had a little silver in it.  I ordered some carda connectors one time and noticed the had solder with silver.  just wondering?  thanks in advance....  If there is already a thread dedicated to this please point me in the right direction.

Tyson Hagerman
Just bought some crack!  Can not wait to try it for the first time.