Bottlehead Forum

Bottlehead Kits => Kaiju Stereo 300B amp => Topic started by: mpdd on March 20, 2016, 11:44:59 AM

Title: Kaiju voltage [resolved]
Post by: mpdd on March 20, 2016, 11:44:59 AM: I'm building a Kaiju, I'm stuck at the Driver Test. "A" side IA, OA and 32U voltages are within specification, "D" side IA voltage is fine, however, "D" side OA is 356, recommended range is 297-303. The potentiometer on "D" maxes out at 160.1 when testing at 46U.
I've tripled checked my wiring, diodes and resistor values. Does anybody have any ideas?
Any help is appreciated.
Title: Re: Kaiju voltage
Post by: ebag4 on March 20, 2016, 12:04:02 PM: On page 64, the 2nd instruction on that page, did you attach to D2 or D8, it should read D8.

Best,
Ed
Title: Re: Kaiju voltage
Post by: mpdd on March 20, 2016, 12:27:25 PM: Thank you, I should have stated that I made the correction.
Title: Re: Kaiju voltage
Post by: fullheadofnothing on March 20, 2016, 03:02:46 PM: Swap 5670s and see if it follows the tube.

Post pictures of the top and bottom of the offending board.
Title: Re: Kaiju voltage
Post by: mpdd on March 20, 2016, 05:39:47 PM: I have switched tubes from side to side and tried a pair of NOS 396A's to no avail.
Photo's attached
Title: Re: Kaiju voltage
Post by: fullheadofnothing on March 20, 2016, 06:24:42 PM: Quote from: fullheadofnothing on March 20, 2016, 03:02:46 PM
Post pictures of the top and bottom of the offending board.
Title: Re: Kaiju voltage
Post by: mpdd on March 21, 2016, 02:16:35 PM: Here are the photo's. The black conductor just broke from 26U as I lifted the board for the photo, that's why it's disconnected.
Title: Re: Kaiju voltage
Post by: ebag4 on March 21, 2016, 02:59:04 PM: Im certainly no expert, but if I were looking for a potential cause for a low voltage situation my guess would be the center solder joint in this portion of your pic.

(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fs20.postimg.org%2Fdrtv4u44d%2Fimage.jpg&hash=7d5fea993d8f5833be59a3b069f45793578e53e7) (http://postimage.org/)

Good luck,
Ed
Title: Re: Kaiju voltage
Post by: drewh1 on March 21, 2016, 03:28:32 PM: Solder joint near white wire middle of board looks suspect as well.
Title: Re: Kaiju voltage
Post by: HiFi Builder Guy on March 21, 2016, 04:44:58 PM: It looks like you are missing the B side LM431.
Title: Re: Kaiju voltage
Post by: mpdd on March 21, 2016, 04:58:37 PM: You're absolutely right. I can't say how many times I've been through the directions piece by piece and stared at that board. The soldering iron is heating up as I write this. Thank you all for taking the time to look at this. I'll post results later. Thanks,
Michael
Title: Re: Kaiju voltage SOLVED
Post by: mpdd on March 21, 2016, 05:53:19 PM: Thanks all, I got the missing LM 431 in that cleared up the voltage issue at OA but was still low at 26 U. I took the board off and touched up all the solder connections, after the resolder everything measures per specification. Thanks again to all of you for taking a look and helping out.