Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Jimb0 on September 24, 2019, 06:39:48 PM

Title: High OB voltage and 1 LED doesn't light up [resolved]
Post by: Jimb0 on September 24, 2019, 06:39:48 PM

Getting 170v at OB and the LED at A8 to Center Pin doesn't light up

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Paul Birkeland on September 24, 2019, 07:08:13 PM

Resolder the center leg of the MJE5731A on that side.  If that doesn't work, posting some photos of the area could be helpful.

-PB

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Jimb0 on September 25, 2019, 08:46:21 AM

Still getting the same readings

Here are some pics

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Paul Birkeland on September 25, 2019, 08:55:25 AM

Did the amp pass its voltage checks with the plate load resistors? 

If this was built with the Speedball from the beginning, this could be an issue of the solder joints at A4/A5 not being solid.

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Jimb0 on September 25, 2019, 09:36:48 AM

I built the amp with the Speedball from the beginning.

I resoldered A4/A5 but to no avail, same readings

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Paul Birkeland on September 25, 2019, 10:04:29 AM

Is the voltage at A8 0V or 12V?

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Jimb0 on September 25, 2019, 11:20:53 AM

A8 is at 14v

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Paul Birkeland on September 25, 2019, 02:43:55 PM

The LED needs to be replaced.  Sometimes they can fail from heat or pulling on the leads tightly, or if they sit in a humid environment they can end up like this once you solder them.

-PB

Title: Re: High OB voltage and 1 LED doesn't light up
Post by: Jimb0 on September 26, 2019, 11:03:29 AM

Thanks PB! Everything is in order now.