Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: FruityPlasmid on April 17, 2018, 08:30:26 AM
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I spent a few days on and off building the Speedball, the first half went well with tests showing I didn't mess anything up, but now with the second bigger board installed the B part (D1 and D2) of the board doesn't light up, and one of the LEDs on the first smaller board, specifically D1 on the A side, doesn't light up. I need some help here, I'm not very good with this stuff
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You'll need to perform the voltage checks in order for us to know what's going on.
Your thread title says that "only half of the tube heats up". Which tube? Which half? What's the indication that this is the case?
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Both halves. I got the measurements
OA - 122.6
OB - 218
G - 0
B+ - 220.1
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Which tube? What's the indication that this is the case?
Can you post small and big board voltages too.
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Here is the small board:
OA - 77.6
IA - 220.7
B-A/B - 0
IB - 220.9
OB - 46.8
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The low voltage at OB on the small board is odd. Was that the voltage you got when you first put in the small PC board.
The voltages at OA and OB on the small board shouldn't move at all when you put the big board in, so if you didn't have 46V at OB previously, then there's certainly cause for concern about how the big board was installed.
The high voltage at OB on the big PC board is unusual considering you are presenting very low voltage to the grid of the 6080 on that side and that there isn't really any high voltage present on the large PC board other than the portion that biases the LEDs.
My suggestion would be to remove the large PC board completely, then recheck the voltages on the small PC board. If the 48V pops back up to where you need it to be, then go over the manual very carefully and check the bottom of the large PC board for unsoldered connections or cold joints. The center leg on the TIP50 is one of those joints in particular that can soak up a lot of heat from your soldering iron, and a cold solder here can manifest some strange voltage problems.
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I will look into that right now, ill give an update on when i am done soon.
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The new readings are:
OA - 0.2
IA - 175.5
B-A/B - 0
IB - 175.5
OB - 45.1
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Now things have gotten much worse, you now have no DC voltage at OA and the persistent low DC voltage at OB.
I would suggest removing the small Speedball board as well, then putting back the resistors and checking that the stock build is still functional.
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There is a very low hum when nothing is playing, turning up the volume makes it louder, but other than that, it works fine
1- 76.5
2- 156
3- 0
4- 156
5- 78.5
6- 0
7- 99.2
8- 0
9- 99.2
10- 0
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Now that the boards are out, can you post photos of each. Showing both the top and bottom may reveal where things went wrong.
Do also check that the two red teflon wires were/are attached to T4. If the one that feeds the big board got attached to T5, you'd end up with some problems.
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here you go
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Looks like you iron was not hot enough for the type of solder you used. Is this lead free solder? Reflowing all the pads on the underside may very well fix things.
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what temperature is optimal for something like this? And yes it contains lead.
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Standard 60/40 or 63/37 is supposed to be good with the iron set at around 650F. But around here we crank the iron up all the way (like 800F) and learn to hold the tip on the work just until the solder liquefies and flows into/around the solder pad and lead. Make sure you get the solder liquid enough for it to form a fillet shape in the joint.
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To add to the wisdom of Doc B, the only components that you could possibly damage from excess soldering are the LEDs. They don't need a ton of heat/solder for a proper joint, but feel free to cook the rest of the parts as much as you need to get the solder to flow into the board.
For each board hole, there's actually plating in the hole, so the solder will eventually flow down into these plated holes and that's how you'll end up with really good joints.
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reinstalling the smaller board gives me:
OA - 78
IA - 157.7
B-A/B - 0
IB - 155.1
OB - 45.3
The led on D1 on B side doesn't turn on
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OK, the resoldering has brought OA back. Can you send us the "after" photos of the small board?
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here you go
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The B side transistors are still not all the way soldered.
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I am having a really hard time getting it to move, ill keep trying, but any recommendations
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Heat and time will make the solder flow. Do you have at least a 30W iron?
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After so much time i did it, and it still acts up
OA - 77.4
IA - 158.7
B-A/B - 0
IB - 158.8
OB - 46.6
I think i broke the LED on D1 side B
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Your LEDs looked to be properly soldered, but not so much the transistors.
If you look in the last photo, the leg of Q1B closes to R1 didn't have solder passing all the way through the hole in the PC board.
I would suggest ordering up some replacement LEDs and taking a breather on this project for a few days while they are in transit.
-PB
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I had some LEDs to spare (bought them previously for the Stock Crack) and it worked fine
OA - 77
IA - 181
B-A/B - 0
IB - 181
OB - 81
But now the big board is acting weird
OA - 144
OB - 213
G - 0
B+ - 213
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Can you pop the big board out and send a photo of the bottom?
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Here you go
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These are still not heated enough. Can you snap a shot of the specs of your solder iron and the solder you're using?
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Tabiger Soldering Iron Kit 60W 110V-Adjustable Temperature
Temperature ranges from 200 C to 450 C
The solder im using is AlphaFry Rosin Core 40/60
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This may be a dumb question but are you keeping the tip clean with something like a damp sponge?
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Also, the temperature should be cranked as high as that iron will go. A 3-5 second heating on all the solder joints except the LEDs should get the solder to flow through those board holes.
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Yes, I do, its ok to ask. I'll be honest, I'm really REALLY bad at this, with the Crack being my first project ever.
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Try a 3-5 second count while you're heating up those joints. You'll see the solder appear to sink a little bit when it wicks into the board through holes.
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I did what you said but i got nothing, maybe i broke the LEDs, I have already broken around 3 of them previously
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LEDs can be tested by some meters by using the diode setting.
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I wish i found that out earlier, 2 of the 4 LEDs don't work
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After replacing the LEDs, i also moved 2N2222A from the A side of the board a little higher, and now the voltages seem to normalize a bit
OA - 110
OB - 198.1
B+ - 181.1
G - 0
i think the issue is that in the manual i doesn't give an example of how high off the transistor should be off of the PCB, so i left it pretty close, but now that i learn how to desolder the leads, i hop tomorrow afternoon i can be done, will update. :)
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It might also help to see how the soldering on the bottom of your board looks.
Having a high voltage at OB means very little current is passing through that half of the big Speedball board, which still points to solder joints or a broken wire (or potentially a flaky solder joint at B2/B5).
-PB
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I made some progress, all the LEDs light up now but OB still has 181V and the LEDs, D1 and D2 on B side, light up almost exactly when i turn the crack on. This was the problem previously but i don't know how i fixed it
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It still looks like there are some soldering issues that are preventing this board from working. It might be worth considering a flat rate repair to get this project up and running.
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I DID IT. What i did exactly was applied more heat to the TIP-50 Transistor to the point where you can see the solder on the top side of the board. Can't wait to have a more extensive listen tomorrow morning