Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: musiciseverything on June 10, 2011, 10:55:14 AM
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I successfully assembled my Crack and was enjoying it. I moved it to another room and now it doesn't work. I went back over the resistance check and voltage check and found that I wasn't getting any resistance or voltage at the transformer terminals. I was worried that initially I overheated the terminals when I began. Now I am pretty sure of it. Is it possible to replace the transformer and try again? Thanks in advance for your help. Tom
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I know this is generally obvious but ... you did check the fuse, yes? Made sure you were getting power from the IEC power entry socket, to the switch, through the switch and to the power transformer (terminal 1 is hot)? Hey, it's probably something I would miss so figured I would ask ...
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Before you replace the transformer I would check the leads that feed it. Seems to me that in the process of moving it something came loose. A joint or power connection maybe.
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Thanks to all. It did seem strange. It is getting power and fuse is good. #1 is hot. I'll keep looking. Is the fuse a 250 V 1 amp sloblow? It is such a great amp with my HD600s. I want it back!
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Sorry, terminal 2 of the transformer is hot (Terminal 2 marked 120V). Neutral goes through the power switch to terminal 1 of transformer but sounds like you're indeed good as far as fuse, switch and iec power inlet is concerned. Anyway, if you are getting line power (115V or so) there then your fuse is good. It is a regular (fast acting) 1 amp I believe. Make sure your solder connections are solid at terminal 1 and 2 and that your ground is solid. If that all checks out, you should have voltage out of the transformers secondary terminals. If not, you could also try and physically inspect the wires at the bottom of the tranformers solder terminals that enter/exit the transformer itself. If you overheated the terminals it would seem possible that maybe one of those wires is dislodged. Not sure how readily fixable that is but it's worth inspecting. Careful in there. UNPLUG.
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Thanks for the info. I will have time next week. BTW, love the moniker.
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Hehe ... Thanks.
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Hello, all. I finally had some time to troubleshoot my Crack and these are the resistance readings:
1 *
2 *
3
4 *
5 *
6 slowly rises to max
7 slowly rises to max
8
9 slowly rises to max
10 slowly rises to max
12 0
13
14 0
20 0
22 0
B3 2.9k
B6 2.9K
RCA Ground 0
RCA center 90K
I have resoldered most of the connections. I would appreciate any assistance. I want my Crack back.
Tom
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I should add that the resistance values for 6,7,9, and 10 go to 410K, if that helps. I also believe that while I was away from home someone might have dropped the amp. Not sure, but I suspect. Thanks for any assistance. Tom
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Check the twisted end leads of the big white resistors, that connects to terminal 3U.
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Thanks, Doc. The solder joint looks good but I will re-solder and check the values again.
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I re-soldered that connection and the values I am reading are the same. Other ideas?
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Is the power transformer still dead?
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Eileen sent me a new one that I just installed and this time I was more careful and my soldering was good without any damage to the transformer. The tabs are clean and all the connections are new and look good. I used some new wire and some of the previous wires but soldered everything new.
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Probably a dumb question on my part but ... Are you checking resistance with the tubes installed?
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Good question. No I am not. Should I?
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OK, assuming that you are making the resistance measurements with the black test lead touching terminal 12, check to see if you have continuity between terminal 3 and terminal 12. You should measure something close to 0 ohms between them, though I notice that you do not have a value for terminal 3 in your readings.
If not 0 ohms (or close, an ohm or two is fine) between 12 and 3, check the solder joints of the black wire from 3 to the volume pot, volume pot to headphone jack, and headphone jack to 12. That is how the two are connected.
If it is 0 then put the black lead on terminal 3 and measure the resistance from 7 to 3 and 9 to 3. That should be 3K ohms. If you are getting a wacky reading there but 12 to 3 is OK it may just be that your meter is being confused by the 100uF electrolytic caps between 6 and 7 and 9 and 10, which may be charging up off of the meter's battery.
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Thanks, Doc. I can't wait to try it when I get back home. I'll work all night I I have to. I have to have my Crack!
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No. The tubes were not installed when I did the testing. Should they be installed while I tested?
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Im Not sure if it would make a difference, which is why I stated it may be a dumb question. But according to manual, they arent installed until after the resistance check. But I thought I would bring it up in case it could have accounted for your resistance measurements being off.
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Doc and others,
Thanks for your help. I rewired the transformer and the re-soldered the connections. One of the resisters needed re-soldering. Bottomline: everything works fine now. I am now enjoying my crack. I am very appreciative of the forum and all the attention to my problem. I believe that I ruined the transformer by over-heating it, and then, with moving it, it failed. I now have headphone bliss. Thanks to all. Next project? Who knows? But, I rest assured that Bottlehead will keep me straight.
Tom G
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All is well. I now have my Crack back. Thanks to all. I am now looking at my next Bottlehead project.
TG
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All is well. I now have my Crack back. Thanks to all. I am now looking at my next Bottlehead project.
TG
Excellent !!! Enjoy.
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Tom,
Nice going! For your next project I'd suggest grabbing the new s.e.x. amp -- that tooo can be used for a headphone amp but with a somewhat different presentation, but also gives you the freedom to experimen with some small (or large and efficient) speakers. nd with the new iron in that kit you probably won't feel so compelled to upgrade to the MQ iron. Also a great little amp and the tubes are quite cheap and last a good long time.
-- Jim
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Thanks, Jim, for the suggestion. I have heard the SEX is even better. I am thinking of giving the crack to my son and building the SEX kit. Right now I'm just enjoying the music through the crack-HD600s. Thanks to all!