Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: jmineart on December 12, 2016, 03:07:57 PM
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Hello,
After a year of no issues with the crack amp w/ speedball, turning the amp on one day resulted in with less than whisper quiet sound in the right channel. I noticed that the A8 led was not lighting. After checking many wires and finding some that needed re-soldered due to joints that dislocated with a slight nudge I have not solved the problem. I have replaced the A8 Led due to what looked to be a bad connection from the wire to the light housing. I checked the led before soldering and it lit up with my multi-meter. Here are the voltages readings. (Reading are right number)
1 75 (176.5)
2 170 (181.5)
3 0 (0)
4 170 (180.7)
5 75 (71.6)
6 0 (0)
7 100 (175)
8 0 (0)
9 100 (105.4)
10 0 (0)
11 0 (0)
12 0 (0)
13 170 (181)
14 0 (0)
15 185 (201)
19 0 (90)
20 206 (0)
A1 75 (71.2)
A2 0 (0)
A3 1.56 (1.56)
A4 0 (0)
A5 0 (0)
A6 75 (176)
A7 0 (0)
A8 1.56 (watched it raise from 0 to 200 mV)
A9 0 (0)
B1 5 (175.6)
B2 170 (180)
B3 100 (174)
B4 75 (71)
B5 170 (180)
B6 100 (105.1)
B7 0 (0)
B8 0 (0)
Also note, when re-soldering I did not have the speedball manual but I dont believe that I misplaced any wires. When I went to download the file from my account my browser crashed and I had lost the file! Google Chrome wasn't working so I used internet explorer to download it, serves me right. It would be fantastic if I could have another file so I can double check the wiring if there does not seem to be a clear fix.
With great thanks,
Jacob
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1) Try another 12AU7
2) Your download count can be increased if I know what order it is. Post your order number or full name.
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I will give that a try.
11997 is the order number.
Thank you.
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It's also possible that the solder joint on the center leg of the MJE350 feeding that channel could use some reheating.
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Looks like the new tube was the answer, thank you for the help!