Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: Ju29 on October 24, 2015, 06:51:58 AM
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Hello,
I built my Crack yesterday (speedball not installed yet). Everything went as it supposed to until the voltage checking (terminal 13 more precisely). My hand shaked and I did a short-circuit touching the 270 ohm 5w resistor (the one between the terminal 21U and the 15U) and the terminal 13 during the checking. There was a sharp little "bang" like a cracker.
The tubes seems to be ok, they still glow..// (?), the fuse is also ok.
As the result I tried the Crack with cheap headphones in cas it could damage my 650. It worked fine until the left hear stopped working in the headphone after a couple of minutes. Then I switched off the Crack for few minutes and turned it on again. It worked ok and then again, the left hear stop after about three minutes.
The voltage changed between before the short-circuit and after (terminals 1 to 12). The ones at zero remained at zero.
HERE ARE MY VOLTAGE MEASURES BEFORE the short circuit () and AFTER :
(The resistance check was spot on. I haven't checked them again since the short-circuit)
Terminal 1 : (before : 83) // after : 89 (should be 75-90)
Terminal 2 and 4 : (173) // 198 (should be 170)
Terminal 5 : (80) // 88 (I have to double check, I wrote it changed to 88 to 0 then 88 and so on) (should be 75-90)
Terminal 7 : (109) // 121 (should be 100)
Terminal 9 : (109) // 0 (!!!) (should be 100)
Terminal 13 : (?) // 198 (should be 170)
Terminal 15 : (?) // 210 (should be 185)
Terminal 21 : (?) // 223 (should be 206)
Terminals A1 and A6 : (?) // 89 (should be 90)
Terminals B1 : (?) 89 (should be 90)
Terminal B2 : (?) // 198 (should be 170)
Terminal B3 : (?) // 121 (should be 100)
Terminal B5 : (?) // 198 (should be 170)
Terminal B6 : (?) // 0 (!!!) (Should be 100)
Terminals 3, 6, 8, 10, 11, 12, 14, 20, A2, A4, A5, A7, A9, B7, B8 : (0) // 0
Clearly there's a problem with the measures of the terminals B6 and 9. They are at 0 instead of 100 (again, the measure of the terminal 9 was ok with 109 before the short-circuit...).
Would someone have an idea of what should I check and should I do to troubleshoot my Crack now ??
My guess is that one of the capacitors is dead or damaged. But that's only my guess (I don't know anything in electronics...). Also the "little" tube has to top black on the inside (seems like black powder). Is that normal ? I didn't pay attention before and don't remember if it looks normal like that... (cf. picture below) It still glow but much less than the "bigger" tube.
THANKS A LOT FOR YOUR HELP ! I was SO close to complete the build without any problem, arghhh.... :)
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Where you had your accident would have no impact on terminals 6-10.
You most likely have a bad solder joint, backwards 100uF capacitor, or wiring error around the octal socket.
-PB
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Thanks for your reply PB !
Ok, I'm going to check again. What I don't understand is that the terminal 9 had the right measure before the short-circuit (I checked several time for each terminal until the 13th and the short circuit...). And then, after the short-circuit, the measure was 0. I guessed it had a link between both. There other incorrect measure (that is at 0 instead of 100) is B6.
So you can confirm me, a short circuit like that cannot damage parts (capacitors or resistors) ? I'm quite sure the short circuit occurred when I touched the 270 ohm 5w resistor and the terminal 15. But I may have seen it wrong and could have been with the terminal 14. Would your analyze would be the same in that case ?
Thanks again,
Julien
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So you can confirm me, a short circuit like that cannot damage parts (capacitors or resistors) ? I'm quite sure the short circuit occurred when I touched the 270 ohm 5w resistor and the terminal 15. But I may have seen it wrong and could have been with the terminal 14. Would your analyze would be the same in that case ?
Terminals 14 and 15 are in the high voltage power supply, terminal 9 and B6 are fairly well isolated from the power supply, so you need to look at the 3K resistor 100uF cap, and associated connections to determine why you have 0V at 9 and B6. (This would've likely presented itself as an issue without the incident at T14/15)
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Ok, quick update.
- I checked again all soldering I wasn't sure and desoldered them.
- checked all the wiring.
- desoldered/resoldered all wires, capacitors and transistor close to Terminal 9 and B6.
- checked the resistance again (all ok).
- checked the voltage and all the measures were almost perfect even for terminal 9 (103) and B6 (102) but for few minutes only... Then Terminal 9 and B6 were at 0 and some others values slightly changed (increased). :'(
As I wrote in my former message, when I tried the headphone, the sound worked perfectly for 2 or 3 minutes and then the sound of the left hear stopped.
I guessed there were a correlation between both so I wanted to try the headphone and checking settings in the same time (safely). I had no other choice to check this (cheap headphones that works perfectly with others devices).
So, after 5 minutes I plugged the Crack again. The sound was perfect and all the voltages measures were almost perfect (even Terminal 9 and B6 at 102 and 103). Then when the sound of the left hear stopped after 2 minutes the measures changed again (terminal 9 and B6 at 0 + other measures that slightly increased).
So..... since the measures are fine for the 2 first minutes I guess my wiring + my solders are both ok..
It remains the hardware (bad components). Am I right ???
What do you think about it ?
If the hardware is the issue, any advices of where I could buy the same components (resistors//capacitors) ?
Thanks for you answers and you help. It will be fixed ! :)
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If you had a failed component, it would never work. An intermittent problem is a solder problem. You have a joint that ceases to make contact as it expands with the heat of running the amplifier. Fix your solder and fix your amp.
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Thank Joshua Paul for your replies. Ok, I understand. I'll check again and will redo the solders.
I hope I'll find the issue soon ! :)
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If you can post photos of your build, we might be able to visually identify the issue.
-PB
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I desoldered in the meantime about 90% of what I built. During this I broke a leg (may be not the right term) of one of the HLMP 600 red led... :-\ I'll have to order some spares.
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And again, thanks a lot for your answers and help btw. It's very appreciated !
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Hello, after reading the instructions of the speedball upgrade (that I got in the same time of the Crack and that I plan to install.. one day :) I realized there were few leds in the package. So I took one and used it so as to rebuild my Crack (I ordered new leds from BH and there are on their way...)
So... I resoldered what I had undone (85/90%) and then check the measurements again.
Resistance check was ok but the exact same pb occurred this the voltage check :
every measurements are fine and after 2 minutes B6 and terminal 9 are at 0 (and the others measures that were fine increased slightly...
Following the instructions of Paul, here are a couple of pictures. I didn't take all solders in pictures but that's a start. Would you mind to have a look at it and tell me what you think ?
Now that I understand the pb is caused by bad solder where could possibly be the location of all the bad solders that could lead for sure to this issue ? I mean, can the pb come from any solders or is it no use to check some because they cannot have any effect on the issue ? (I hope I'm clear, english is not my first language so I try my best.. :) )
Thanks a lot,
Julien
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The black wires at 3 could do with some solder both sides of the tag strip but I don't think that is your problem area.
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Ok, I desoldered at least twice each of them. Others solders, closed/linked to B6 and T9, more than that...
...and the same pb occurs.
Now, honestly I'm completely lost and really don't know what to do next. I feel sad and frustrated to have spent so many hours (days) for nothing. I just don't get it. I know it's an easy kit and there's no billion of places to check. With the $$ conversion, repair service is about 170$ + shipping (CAD) so it's not quite really an option for me right now.
I know I repeat myself with this question but does it have to be a bad soldering, for sure ?
Are there specifics checking I could do to try to locate the issue very precisely ?
(Thanks Deluk for your reply at my last message. I checked also this one but didn't solve the pb)
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Both sides of the tubes light up?
It happens after something grts hot enough, 2 mins. And all solder joints are rewetted/ reheated.
Is it unthinkable that there is a problem with the 6080 tube?
Maybe it should be swapped for another one?
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Yes, the 6080 lights on both sides and much more than the other small one. I've just checked, both still glow when the music stop in my left hear.
I attach 2 pics of them.
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Might be grasping at straws here. Have You take the 6080 out and cleaned the pins and checked that the socket is tight for all pins?
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Hi, I checked and the socket tight for all pins and for both tubes.
I didn't mention because I hadn't really paid attention but when I switch on the crack only one hear (the right one) works for about 10 to 15 seconds. Then there's a pop in the left hear and the crack works fine for 3 to 6 minutes. And after that no sound on the left hear anymore.
Resoldered again a few this morning but same pb. Can the issue be related to the headphone jack or there's absolutely no link between this part and my pb ?
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Isn't it also possible it could be a nicked/broken wire rather than a soldering problem? Might be time to try a careful chopstick test to see if wire movement causes any static/pops/noise.
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Thanks for your reply Dale. I asked myself this when I almost desoldered everything the first time. I would remplace a couple of wires just be 100% sure but I don't have that much left. Do you know if there's a way to check their integrity them without removing/desoldering them ?
I also wonder if one of the tube sockets could be the pb (just a suggestion... I don't know if that's possible // ??)
....Is HAS to be somewhere..
I will resolder few others later, again... For now I do have to go on my guitar build. Much easier :-\
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Again, This looks like intermittent contact. Perhaps a solder joint that you are missing each time you go around them or perhaps a broken wire as suggested by others. Taking apart your build and putting it back together is also an occasion to break parts. Some joints with multiple wires or parts require more heat and solder to be adequate. You do not necessarily have to undo the connexions to make them sound, only reheat them and apply a bit more solder. Make sure you have good mechanical connexion (good loop around the terminal) before soldering.
I would suggest that you ask a friend to look at your build and check it against the manual. A fresh pair of eyes could see something that you keep missing.
As PB said, measure the 3K resistor between 3U and 9L to make sure it is good and inspect around there to see that everything is okay.
I am not an electrician, but some of your voltages that are on the high limit side might be related to your mains voltage. I had similar readings in some of my kits, and found out that the voltage coming into my house was around 125 volts. The manual says that the voltages were made with an AC mains voltage of 119VAC.
Where in Canada are you located? I am in Montreal. I could look at your amp if you are nearby. I have spare tubes and parts for the Crack.
Richard
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Just a troubleshooting suggestion, but the fact that you are able to repeatedly create these symptoms makes a big difference. Next time you get a chance to work on your amp run it upside down in the base, or on books, etc. The key is to have easy access to the bottom so you can perform a complete voltage check while the problem is occurring. Post any voltages here that are out of spec and someone a lot more knowledgable than me will help you sort it out. If the voltages are all good when the sound stops then I'd look long and hard at the signal path wiring. Paul B can help you trace that by taking measurements with your meter while playing a test tone.
And if you can't reproduce the problem with the amp upside down you'll just have to build a clear cover and run it that way from now on! Just kidding😀. If you can't reproduce the problem with it upside down that provides clues too. That would send me looking for a mechanical issue caused by gravity when the amp is in the base.
Don't get discouraged. PB and the rest of the BH team are great at solving these tough issues and won't give up until your amp is fixed.
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Thanks for your replies. Offer very appreciated Richard, thanks. I stay in Hull close to Ottawa. No trip scheduled to Mtl soon but if my plan changes (and if have still have the pb at this time) I'll let you know... The 3K resistors measurements are ok (and the others resistors as well). Well noted also about the two others pairs of eyes around me.. :)
Ken I did that already. I've posted my voltage measurements when the pb occur : every measurements are perfects when both sides work in my headphone. When the left side stops after a couple of minutes, B6 and T9 are down to 0 and almost all others voltage measurements increase slightly (see my first message for the exacts measures). I've also made once a resistance check when the issue occur I got 0.08 at T6 and T10 instead of 2.9K but I didn't repeated the measurement. So that is based on a one time measurement... Also the RCA jack (white) seemed to be at 0 or at least I wasn't able to measure anything (the red one was at 98). And the pb occur when the crack is on both sides (so no need to get a clear clover... :)
About the soldering I made sure for each of them that there were a good/large contact between the wire and the terminals. When I destructed the crack I removed the solder/used sandpaper and used a sharp knife to scratch a little bit the terminals to make sure there would be a good contact. Then I resoldered as I said before. Since I do as Grainger kindly advised me in his message, last paragraph.
About the BH team, yes I hope so.. Without any news from them since a couple of days I guess I have to continue to use my solder and check and recheck my solders..
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Once the problem occurs, can you confirm that your voltages on terminals 1-5 are still correct? (You are right, they will pop up a bit)
Once you have the problem and are able to measure your voltages, try measuring the voltages on B1-B3.
In particular, I'd like to see if B1 and terminal 1 have different voltages when the problem occurs.
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Hi Paul, thanks for your reply.
From my notes :
Terminal 1 : 83 before the pb // then 89 when the pb occur
Terminal 2 : 173 before the pb // then 198 when the pb occur
Terminal 3 : 0 before the pb // then 0 when the pb occur
Terminal 4 : 173 before the pb // then 197 when the pb occur
Terminal 5 : 80 before the pb // then 88 when the pb occur
B1 : 83 before the pb // then 89 when the pb occur
B2 : 172 before the pb // then 194 when the pb occur
B3 : not quite sure one this one // then 121 when the pb occur
I have to leave in a couple of minutes. I will do an other measurements in a few hours when I'll be back. I measured many time and every time the result was the same result. But again, I'll do an other test just to be 100% sure.
Thanks !
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Oops, I got mixed up (thought 7 was the issue).
Try the same test on B4, B5, B6 and terminals 5 and 9.
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Since the left hear doesn't work for the first 10 to 15 seconds I thought that would be a good idea to get the measurement as well for this short time. So I plugged/unplugged a couple of time, waiting a minute between two measures. 10 seconds is a short time and and wanted to get accurate measures.
So here are my fresh voltage measurements I've just made :
B4 : the 10 first seconds 89 // then 79 for 3 to 6 minutes // then back to 89
B5 : the 10 first seconds 238 (!!!)[/b] // then 170 for 3 to 6 minutes // then 194
B6 : the 10 first seconds 0 // then 103 for 3 to 6 minutes // then back to 0
T5 : the 10 first seconds 230 (!!!)[/b] // then 79 for 3 to 6 minutes // then 89
T9 : the 10 first seconds 0 // then 103 for 3 to 6 minutes // then back to 0
Others measures (just in case) :
B1 : the 10 first seconds (?) // then 83 for 3 to 6 minutes // then 89
B2 : the 10 first seconds (?) // then 170 for 3 to 6 minutes // then 194
B3 : the 10 first seconds (?) // then 107 for 3 to 6 minutes // then 120
B7 : the 10 first seconds (?) // then 0 for 3 to 6 minutes // then 0
B8 : the 10 first seconds (?) // then 0 for 3 to 6 minutes // then 0
T1 : the 10 first seconds (?) // then 83 for 3 to 6 minutes // then 89/b]
T2 : the 10 first seconds (?) // then 170 for 3 to 6 minutes // then 194
T3 : the 10 first seconds (?) // then 0 for 3 to 6 minutes // then 0
T4 : the 10 first seconds (?) // then 170 for 3 to 6 minutes // then 194
T6 : the 10 first seconds (?) // then 79 for 3 to 6 minutes // then 89
T7 : the 10 first seconds (?) // then 107 for 3 to 6 minutes // then 120
T8 : the 10 first seconds (?) // then 0 for 3 to 6 minutes // then 0
T10 : the 10 first seconds (?) // then 0 for 3 to 6 minutes // then 0
I wait for you feed back. Thanks for your help !
PS: I may be completely wrong but I have the impression to hear something (in the bulb I think) when the measures changes.
PS2: It will work !
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PS2: It will work !
Yeah, we'll get you there.
Ok, I have one odd suggestion for you that will about wrap up the diagnosis. Remove the wire at B3 and remove the wire at B6 (just at the octal socket end, you can leave each free end poking up and hanging in the air).
Wire a temporary jumper from terminal 7 to B6 and a temporary jumper from terminal 9 to B3.
Now remeasure and see if the 0V reading has moved terminals or remains where it was.
-PB
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Argh, I was so proud of this solders. B3 and B6 were my favorites !!
Just kidding.. :)
Here are the measures :
B4 : the 10 first seconds 0 // then 0 for 8 minutes (didn't wait any further).
B5 : the 10 first seconds 238 // then 194 for 8 minutes (didn't wait any further).
B6 : 0 // then grow slowly during the 10 seconds to stop at 119. Didn't change after for 8 minutes (didn't wait any further).
T5 : the 10 first seconds 230 // then 89 for 8 minutes (didn't wait any further).
T9 : the 10 first seconds 0 // then still 0 for 8 minutes (didn't wait any further).
Fingers crossed..
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If B6 never fell back to 0V, then we can conclude that the 6080 is working properly, the socket is working properly, the solder joint at B5 is good, the solder joint at B4 is good (despite your 0V reading at B4, which isn't possible based on all other information), and that the path from ground, through the 3K resistor, and to the terminal strip is working on the headphone jack side of the amp, but not the volume pot side of the amp. This also confirms that the 12AU7 is doing what it needs to do to bias both halves of the 6080 properly.
This is absolutely a flaky connection, likely at terminal 3 or terminal 9.
It might help to triple check the resistance between terminal 3 and terminal 9, to make sure that terminals 9 and 10 don't have any debris between them that's conducting, etc.
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Hi I've posted the wrong measures...
(I removed B4 instead of B3 so the former measures are not what you asked me...)
I post the right one in few minutes....
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Ok removed B3 and B6 and put B3 to T9 and B6 to T7
I was able to measure only B4 (230) and B5 (238) then few seconds after there was some smoke/smell.
I think it's the resistor of 22.1K (the one the closest to the headphone plug) that started to burn...
I unplugged as soon as I realized there were some smoke. It stayed plugged for maximum 5 seconds.
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Ok removed B3 and B6 and put B3 to T9 and B6 to T7
I was able to measure only B4 (230) and B5 (238) then few seconds after there was some smoke/smell.
I think it's the resistor of 22.1K (the one the closest to the headphone plug) that started to burn...
You must've wired something to T6 or T10 by mistake.
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You're right (of course you are ! :) the alligator clip from T9 touched T10.. Argh, haven't seen it...
Measures in couple of minutes...
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B4 : the 10 first seconds 230 // then 80 for 3 to 6 minutes // then 89
B5 : the 10 first seconds 238 // then 170 for 3 to 6 minutes // then 194
B6 : the 10 first seconds 0 // then 103 for 3 to 6 minutes // then back to 0
T5 : the 10 first seconds 230 // then 80 for 3 to 6 minutes // then 89
T9 : the 10 first seconds 0 increase slowly to 103 // so 107 for 3 to 6 minutes // then to 119
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We will mail you a replacement 6080. The intermittent nature may suggest that the tube is actually not properly soldered itself. If possible, please update your forum signature with your name (first initial and last name is sufficient) so that I can get this in the mail tomorrow for you.
-PB
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Ok, thanks Paul for the follow up. Appreciated. Let me know when you'll identify me with my signature. Then I'll change it after.
About the results/measures I suppose you're 100% sure of your verdict (for me the numbers I give you are just like chinese...). But if you need more tests/measurements to confirm it, just let me know and I'll proceed...
Have a good day/evening
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Little update of my situation...
I was to impatient to know if the tube was the issue, I ordered last week a cheap 6080 from Tubedepot.
The 6080 received 2 days later, I installed it and since... my Crack works perfectly.
So there it was... the 6080 tube...
THANKS Paul and everyone for the help to troubleshoot my Crack. The good point is that I practiced a lot (I mean a lot !) my soldering skills. I think that it helped me during the speedball upgrade I've just done tonight. So nothing happens for nothing... I've been listening for music for something like an hour tonight with the speedball upgrade and I enjoy every seconds of it.
Next step, try few others 12AU7-like tubes. But no rush, I just need to enjoy the music now... :)
Have a good night (/day)