Bottlehead Forum

Bottlehead Kits => S.E.X. Kit => Topic started by: Mordicai on February 24, 2016, 06:35:37 AM

Title: ONE CHANNEL ON C4S BOARD [resolved]
Post by: Mordicai on February 24, 2016, 06:35:37 AM

After enjoying this amp for a few days I decided to install the C4S board. A side works fine. Nothing  on the B side. OA voltage 74: OB voltage -1.1. Both 10 and 20, 415v. The  right hand LED on the B side does not light up. The other three are bright. After a day of checking everything touching up everything on the B side without success, Im not sure where to go from here. Is it possible the LED is no good. It seems like it has a very, very  faint red glow towards the bottom of the LED, but I'm not sure.

Title: Re: ONE CHANNEL ON C4S BOARD
Post by: Doc B. on February 24, 2016, 06:55:17 AM

Could be the connections of the 2907 transistor. I would double check that the correct lead is in each pad and that the pads are well soldered. Ditto the big transistor, double check the orientation and the integrity of the solder joints of the pads it is mounted to.

Title: Re: ONE CHANNEL ON C4S BOARD
Post by: Mordicai on February 24, 2016, 07:25:29 AM

Hey Doc, Went over those connection just now with no success. Everything is in the right holes and resoldered them all . Still - 1.1 at OB with three LED's

Title: Re: ONE CHANNEL ON C4S BOARD
Post by: Mordicai on February 24, 2016, 07:33:39 AM

Got it Doc. Solder those LED leads for the third time with a smaller tip. Didn't have connection to the pad. Thank you for your time....Max

Title: Re: ONE CHANNEL ON C4S BOARD
Post by: Doc B. on February 24, 2016, 07:52:48 AM

Good work! A magnifier can really help to inspect those teeny pad connections.