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November 12, 2019, 02:34:49 AM

Author Topic: Crack finish. Volts problems.  (Read 168 times)

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Offline michael30

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Crack finish. Volts problems.
« on: November 10, 2019, 07:32:32 AM »
Hello everyone
I finished the crack and checked the volts.
First of all,one of the LEDs do not light up.
These are the test results:
terminals-
1:  157.6
2:  173.7
3:  0
4:  174.5
5:  86.6

6:  0
7:  159
8:  0
9:  112.2
10:  0

I over checked all the wiring.. looks good.
i'm new so i can't point at the problem.
Ty for help!
« Last Edit: November 10, 2019, 07:34:47 AM by michael30 »

Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #1 on: November 10, 2019, 07:56:23 AM »
Do you see both sides of the 12AU7 glowing?

Can you very carefully check the voltage on A8?

Generally this is not related to the LED itself, so resist the urge to reflow the solder joints around the LED, as excess heat can damage them.
Paul "PB" Birkeland

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Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #2 on: November 10, 2019, 08:50:30 AM »
Yes, 12U is OK as a ground.  Terminals 1 and 7 will fall into line based on the information we find from the voltage measurement at terminal A8.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline michael30

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Re: Crack finish. Volts problems.
« Reply #3 on: November 10, 2019, 08:53:11 AM »
A8 Voltage is 18.57.
I deleted the comment before by a mistake.
« Last Edit: November 10, 2019, 08:56:19 AM by michael30 »

Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #4 on: November 10, 2019, 10:34:05 AM »
That is generally indicative that the LED has been cooked and is no longer working.  You can connect a piece of wire between A3 and A8, then in all likelihood you will find that your voltages are proper.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline michael30

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Re: Crack finish. Volts problems.
« Reply #5 on: November 10, 2019, 10:44:07 AM »
Ok I did as u said.
Terminal 1 read: 86.6V
Terminal 2 read: 112.6V.

I will order a new led.

Offline michael30

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Re: Crack finish. Volts problems.
« Reply #6 on: November 10, 2019, 10:57:51 AM »
I just found a replacement HLMP-6000 LED in my garage.
it doesn't have banded side like yours.. Can i use it?

Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #7 on: November 10, 2019, 11:24:55 AM »
If you can't tell which end is the cathode, it's not a good idea.  They also absorb moisture over time, and a garage is pretty humid.

112V is still a little high, what DC voltage do you see at A7?
Paul "PB" Birkeland

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Offline michael30

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Re: Crack finish. Volts problems.
« Reply #8 on: November 10, 2019, 11:59:07 AM »
If you can't tell which end is the cathode, it's not a good idea.  They also absorb moisture over time, and a garage is pretty humid.

112V is still a little high, what DC voltage do you see at A7?

Btw i meant Terminal 7.. but you got me.
anyway i read 0 for A7.

https://postimg.cc/jCSgK6tR
« Last Edit: November 10, 2019, 12:01:37 PM by michael30 »

Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #9 on: November 10, 2019, 12:06:46 PM »
I would reflow A5 a bit. 

Can you list your voltages on terminals 1-10 again as the amp is now?

-PB
Paul "PB" Birkeland

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Offline michael30

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Re: Crack finish. Volts problems.
« Reply #10 on: November 10, 2019, 12:34:20 PM »
Thank you for fast respond.
The new reads:
1)  85.7
2)  179.4
3)  0
4)  179.4
5)  89

6)  0
7)  111.6
8)  0
9)  114.6
10)  0

Both LEDs glowing. https://i.postimg.cc/wTTy1ZCT/IMG-9761.jpg

Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #11 on: November 10, 2019, 01:05:23 PM »
That's a working amp.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline michael30

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Re: Crack finish. Volts problems.
« Reply #12 on: November 10, 2019, 01:11:04 PM »
Cool, Thanks!
Can I run it for now with the wire A3-A8 until the new LEDs will arrive?

Offline Paul Birkeland

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Re: Crack finish. Volts problems.
« Reply #13 on: November 10, 2019, 01:24:22 PM »
You can run it with the wire there forever if you'd like.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline michael30

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Re: Crack finish. Volts problems.
« Reply #14 on: November 10, 2019, 07:48:54 PM »
Update Voltages after soldering wire a3-a8.

1) 85

2) 184
3)0
4)184
5) 0

6)0
7)113.5
8)0
9)116
10) 0

after soldering reasults.