Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: andyh on January 13, 2021, 12:20:52 AM
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I think I must have missed something but can't see it. Voltage check
1 -0.7
2 -0.7
3 0
4 -0.7
5 -0.7
6 0
7 0
8 0
9 0
10 0
I,ve gone all the way through the manual following the wiring instructions and can see nothing wrong/incorrect. :'(
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First thing I'd do is check the fuse......................
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Tubes are glowing so assuming it's ok. (Checked, fuse is ok)
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Make sure that (1) you've got the test leads plugged into the correct jacks on the meter; and (2) you've got the meter set to measure DC volts not AC volts.
cheers, Derek
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Yes checked, also checked with a second meter just in case.
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I see a diode lead at 19L that's poking out and maybe touching another lead, which will short out your HV supply (and should blow the fuse).
Can you perform the power transformer voltage test that's in the manual and let us know what you get on the high voltage winding? (The one that should be about 160V)
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Hi Paul,
Black lead to term' 11 red to 12 on transformer, it's reading 175v.
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How about the DC voltage between terminal 20 and 21?
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235v
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Any ideas anyone??
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How about the DC voltage between terminal 3 and terminal 20?
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3-20 = 0v
out of curiosity I measured 3-19 =90.7v
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How about the DC voltage between terminal 3 and terminal 15?
and the DC voltage between terminal 3 and terminal 13?
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3-15 = 196v
3-13 = 172v
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Voltages between 3 and B2?
3 and B5?
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Both 173v
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OK, now measure the DC voltages between 3 and 2, as well as 4 and 2.
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I did move the capacitor near 20/21, and poked around with the diodes there as you was showing an interest in that area.
So out of curiosity as there is power there I've redone voltage check.
Results are
1 = 94.7v
2 = 172.9v
3 = 0.4v
4 = 173.6v
5 = 90.2
6 = 0.4
7 = 113.2v
8 = 0.7v
9 = 115.5v
10 = 0.4v
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You may just have a loose connection or two. Those are working voltages, out of curiosity, can you carefully measure the voltages at A3 and A8?
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Both 174v
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No, A3 and A8 wouldn't be 174V. That is pin 3 and pin 8 on the 9 pin socket. No pins on the 9 pin socket should read that high (although 1 and 6 will for about ten seconds when you first turn the amp on).
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Sorry crossed wires excuse the pun,, is that 12u to a3, a8?
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2-3 = 174v
2-4 = 0v
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I think you meant 3 - a3 3 - a8 are both 1.5v
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Yes, 3 is a ground. It looks like your amp is working properly now. I would poke around with a wooden chopstick and a cheap pair of headphones plugged into the amp to be sure nothing causes a popping noise when you poke around in there. If you have a loose connection and you poke it, you will get a pop through your headphones and that can help refocus your efforts.
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Thank you so much for your help I really appreciate it.