Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: EmiTo on June 05, 2023, 12:12:42 PM
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The amplifier had been working properly for a while but the amplifier doesn't produce any sound now, the resistance check is fine but the voltage check is not, I'll post both values and some pictures if those help.
Resistance check:
1. 68 Kohm
2. 58 Kohm
3. 0.5 ohm
4. 2.9 Mohm
5. 2.5 Mohm
6. 0.6 ohm
7. 2.97 Kohm
8. 0.5 ohm
9. 2.94 Kohm
10. 0.5 ohm
12. 0.5 ohm
13. 1.21 Mohm
14. 0.5 ohm
20. 0.5 ohm
22. 0.4 ohm
B3 2.97 Kohm
B6 2.94 Kohm
RCA1 101.2 Kohm
RCA2 89.7 Kohm
RCA ground 0.5 and 0.6 ohm
Voltage check:
1. -0.7 V
2. -0.7 V
3. 0 V
4. -0.7 V
5. -0.7 V
6. 0 V
7. 50 mV
8. 0 V
9. 71 mV
10. 0 V
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Do the tubes glow when you turn the amp on?
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yes, they glow
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What's the DC voltage at terminal 13?
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It's -0.72 V
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How about 15 and 21?
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it's -0.66 V for terminal 15 and -0.63 V for terminal 21, also I remeasured terminal 13 and it was -0.63 V this time around
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Set your meter to AC volts and measure between terminals 18 and 19.
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It was 168.3 V AC
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Was or is?
Can you measure the DC voltage between terminals 20 and 21? (black probe on 20, red on 21)
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So some stuff happened, it is 168.3 V AC but when i tried to measure terminals 20 and 21 i got 170 V and then it started to go down slowly, then i remeasured the AC Voltage between 18 and 19 and got 0 V, I checked the fuse and it was blown, replaced it, tried to measure 20 and 21 again and blew another fuse, replaced it again and then every measurement was regular and sound is back again.
Should i check something to make sure I don't blow another fuse or just so I don't get those irregular measurements?
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I would look for component leads that are touching or close to touching other leads or the chassis, as well as for loose connections. I would not consider your amplifier fixed.
It's likely that if you run the amp and poke around with a wooden chopstick, you should be able to poke the problematic area and see the LEDs go out up front.