Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Strikkflypilot on April 20, 2014, 05:52:56 AM
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Hi again!
After Caucasian gave me he ok on voltages on stock crack I really enjoyed it and moved on to speedball.
Built everything but now problems.
LED A3 is NOT lighting up. All others do.
Tubes light up.
Terminals:
1. 73,25v
2. 220,5v
3. 0v
4. 220,3v
5. Fluctuating in the -0,something v range!
6. 0v
7. Falling slowly from 200v range
8. 0v
9. Slowly falls from 100v range
10. 0
11. 0
12. 0
13. 220v
14. 0v
15. 225v
20. 0 v
21. 230v
Thoughts? I mean help:)
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Resolder the center leg of the MJE-350 placed on the PC board that feeds terminal 5.
(Also, don't poke at the LED on A3, it isn't lighting because of other circumstances)
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Thank You.
I resoldered all the leads of the MJE on the right board.
No change.
Then I did the same with the left board
No change.
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Can you see both halves of the 12AU7 glowing?
Can you verify that the "I" and "O" wires are leaving the board that feeds T5 properly?
It's very easy to put a 2N2222A in place of a 2N2907, so that's good to check too.
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Hi and thanks for this.
Both halves of both tubes are glowing.
On the right board, the I is connected to 4u
The O is connected to 5u.
The G is connected to 3u.
The large board has both the 2N2222As connected.
The small boards have the 2N2907As connected
All properly aligned.
I have freshened up the solder on terminals 3u- 5u
Same results.
Additionally the LEDS on the big board are shining bright, like theA8 LED.
The LEDs on the small boards are alle more dim, A3 does not light up at all, at
least not visible to me.
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You can try swapping the small PC boards left to right, to see if your voltage issue moves to terminal 1.
This still seems like a cold or missing solder joint on that small PC board.
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Thanks again!
It was indeed board B.
The "B" leg had a layer of rosin around it and what looked like a good joint wasnt conducting.
Used the conductivity test of my meter to pinpoint.
ALL LEDs light up.
1. 64v!
2. 215,3v!
3. 0v
4. 214v!
5. 76v
6. 0v
7. Slowly falling from 200v!
8. 0v
9. Slowly falling from 200v!
10. 0v
11. 0v
12. 0v
13. 216,6v!
14. -(minus) 0v!
15. 221,8v!
20. -(minus) 0v!
21. 227,4v!
What do You think of these? Not quite what I expected.
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Do 7 and 9 settle somewhere?
They shouldn't really pop up to 200V, that would tend to suggest a miswire on the larger PC board. (On the B+ pad on that board is at 200V, almost all the rest of the pieces are at no more than +5V, then the collector of each Tip 50C will be at ~100V)
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Seems to be same problem with the 2N2222As
Also I got a short spark when testing conductivity just touching red probe to center leg of the TIP50 closest to the RCAs
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Resolderedthe 2N2222As legs.
New startup.
Small boards leds light up A3 lights up A8 flickrrs slightly then lights up.
The two big board leds (where there was a spark from tip50 middle leg) dont light up.
1. Rises quickly to 220v! Then goes down to ca 30 and up again to 67v from where it slowly goes downward
2 slow fall from 100v
3. 0v
4. Slow fall from 100v
5. 75,5v
6. 0v
7. After settling slowly falls from 64v
8. 0 v
9. Slow fall from 78v
10 0 v
11. 0v
12. 0v
13. Slow fall from 100v
14. -0v
15. 143,78v
20. -0v
21. 193v
And I hope the orientation of the large speeboard PCB Isnt crucial. The TOP side points towards pot
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Can you measure the DC voltages with the "rising" or "falling", put the probe on and report the reading after it stabilizes.
-PB
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I have a bad feeling about this now.
What are the odds that components are irreparably distorted or broken?
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I still don't have a feeling for what's going on in your amplifier.
Can you post the voltages that you end up with? (Not the behavior, just what they settle to)
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Thanks for Your help PB.
Will get back to this build when time permits.
If only I had measured continuity for every solder, don't like the idea of having sent Voltage thru an incomplete curcuit.
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I decided to remove the speedball upgrade and revert to stock, all Voltages are good,
SQ is just as excellent as before.
Going to resolder all points of the boards and be back with a report.
I am considering the fact that possibly very high Voltages flew through the speedball parts,
However if they conduct well and voltages are good, all is well, don't You think?
Edit: Any other way of testing the Speedball boards before soldering them into the Crack curcuit?
By the way, this pic is for JamieMcC:)
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Hi.
I guess You didn't see my edit of the last post or it is Sunday.
I now went ahead and checked all solders on the PCBs. They seem solid.
Being no expert I cannot check the transistors properly but the NPNs have high resistance to the emitters and collectors although not identical and the PNPs have high measurable resistances.
I did find a diode that has no voltage drop, maybe related to the spark from the collector of the adjacent TIP50 during my conduction test after voltage tests(after unplugging of course)
I also noticed that the diodes have different voltage drops. Some around 0,75v that don't light up and some at around 1,5v that light up.
Anyway.
The final culprit seems to me to be just one small diode.
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Your meter's ability measure to the LED voltage drop while they are installed on the PC board is not an indicator of how they function. For most meters I own, only one of the LED's can be measured. A few meters will not be able to measure either, and some will be able to measure both.
If the LED isn't in backwards and hasn't visibly exploded, then you can assume that it's working.
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Thanks for the reply
It just fitted the picture, being one of the two LEDS that didn't light up.
Putting the PCBs back into the curcuit like they are now would only put me back with funky numbers as I haven't changed anything...
Nothing else I could do to troubleshoot before reinstall?
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I'd post a photo of the top and bottom of the big PC board, we may be able to spot something that you haven't spotted yet.
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Appreciate Your help.
Here are the pics. You will notice that the emitter leg of one of the 2N2s hardly has solder, but it is on the end where the LEDs did light up and and conduction test is good from that leg to the leg of the small resistor it is connected to on the PCB. That or anything else strike You as rotten?
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I would say that there is a little too much solder on the underside of that PC board. Some of it may have wicked up under those 2N2222A's and shorted the case to other legs.
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So I ve tried again.
Enjoyed the stock crack immensely for two days or so.
Now I have resoldered ALL the speedball legs and ALL the
terminals.
Like last time, the two leds on the bigboard close to the PS
wont light up.
Before I soldered the PCBs I checked all the conducting and AGAIN,
only the one diode closest to the TIP50 on the side that doesnt
Light up measures weird.
I couldnt find a voltage drop or measurable resistanc over
it, no matter the polarity of the testing
I would already have ordered a replacement but cant find a replacement
6000.
Do You think something else is wrong?
1. Drop from 65v
2. Drop from 100v
3. 16mV
4. Drop from 100v
5. 75,92v
6. 16mV
7. Drop from 65v
8. 16mv
9. 77,6V
10. 16mV
11. 16mv
12. 0v
13. Drop from 100v
14. 0v
15. 144v
20. 0v
21. 193,1v.
Am I missing something?
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Can you try rotating the big pc board 180 degrees and installing it that way.
If so, does the same side stay dark?
If the dark side also rotates with the board, then I would replace both the transistors on that side, using as little solder on the 2N2222A's as is possible.
If the dark side remains to the rear of the amp, then there is a wiring issue with the installation that we can troubleshoot at that time.
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And 180 degrees
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Well done.
Yes, that is fried transistor(s).
-PB
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I thank You Sir.
I did have a spark from the middle leg of That
particular TIP50 during conduction test. At that point the
2N2s had bad solders.
My theory is that the one LED I keep writing about bought it
since, well, Ive gone on and on about it enough.
So I replace the TIP50, 2N2222A and, indulge me :), the dead LED
on the dark half of the bigboard, yes?
Would You be so kind to mail me their datasheets so I order the right ones?
Yours truly
Strikkflypilot
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A blown LED will literally explode. Yours is OK.
Any old tip50 will work. The 2N2222A should be in a metal can, but otherwise the variations aren't super important.
PB
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I have ordered two of a kind from different manufacturers.
Would You have changed transistors on both sides or just the one
currently without current? Just so they are as similar as possible?
Lots of people go on about how material changes makes all the difference
in sound quality.
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I would focus on getting the dark side to work first.
-PB
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Thanks.
Will do as soon as they are delivered.
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Thanks for all help thus far, CB.
I Removed all transistor/LEDs on the dark half
LEDs had no voltage drop, even out of curcuit
The 2N2222A was kinda dark/ blueishblack and burned looking
The TIP50 looked good but I changed it all the same.
After reconnecting, all LEDs lighted up and Voltages are good.
Just haven't had time to listen in yet. Very excited
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Ok.
Was excited to try some music
I switch the crack + SB on.
After about 6 seconds the 6080 lights up blueish before it lights as usual(wires in reddish light) after about 10 seconds, when a humming starts (about 80-85 Hz like a ground loop?)that is first noticabe on the left, then also on the right channel although slightly weaker. This humming gets considerably louder up to 20 seconds. On a cold amp it wears out at about 60 seconds. Faster on hot amp, maybe 15 seconds after it gets loud.
From then on it is quiet until I turn the volume all the way down which makes the noise on both channels with max noise. When I turn the volume all the way up to 100% it is also noise with left>right. In between it is quiet
If I attach a source, there is only a slight hum which gets louder from about 70% volume to 100%. Ig I turn volume all the way down, the noise is back to max binaurally.
In between, as in 0%<,>100% the Sound quality seems sweet, but it is overshadowed by the other issues...
Again I ask for help. And of course, here are the voltages witj SB installed:
1. 73,4 v
2. 173,45 v
3. 0 v
4. 173,41 v
5. 76,8 v
6. 0 v
7. 101,86
8. 0 v
9. 102,8 v
10. 0 v
11. 0 v
12. 0 v
13. 173,1 v
14. 0 v
15. 192,33 v
16. 0v
17. 0 v
18. 87 v
19. 82,7 v
20. 0 v
21. 211,4 v
Hope this can be resolved.
Yours truly
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On a cold amp it wears out at about 60 seconds. Faster on hot amp, maybe 15 seconds after it gets loud.
This is noise that occurs during warmup, there isn't really anything to troubleshoot here.
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Good to hear, really, but the constant noise at volume level 0 and the blue flash in the 6080 at 7 seconds is nothing to worry about or possible to mend? (ESpecially the volume 0 buzz is rather annoying and wasnt there before the SB)
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The warmup characteristics of the amplifier change when installing the Speedball.
If you can't live with a bit of warmup time, you can reinstall the 22K resistors.
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Thanks again for the reply. Appreciate Your diligence with this matter.
I can certainly live with the warmup time, just wasnt expecting it.
Is there a way to eliminate the loud buzz at 0 volume? It does NOT go away.
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I am looking into replicating the issue with one of our Cracks and coming up with a solution.
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Well, Caucasian Backplate.
After leaving it on a couple more minutes, also the 0 Volume buzz disappeard, like You said.
Shame on me :-[
I thank You very much for ALL Your help.
My amp is now working as designed.
Long Norwegian summernights with the classics ahead:)
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Hi Strikkflypilot,
I have the exact same behaviour with my Crack+Speedball built a couple of weeks ago. Stock crack was completely silent, then with the speedball fitted I get mains hum at the start, getting louder then receding, and a low-volume buzz that goes away after a couple of minutes. I did all the suggested checks and am satisfied that the build is OK. I am more than happy with the sound. It did scare me the first time I heard the hum as I feared it would get ever-louder and break my HD650s (not to mention my ears) but happily not.
Cheers
Paul.
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Thanks, pduk.
Nice to get that kind of feedback from a fellow builder.
Caucasian sure has walked me through this very thoroughly.
I hope the questions asked and answered will help those that also eventually will have questions of their own when building.
I could not be happier with the support here.
My most important tip for upcoming builders is this:
Check all solder joints! Not only by looking but with Your Multimeters.