Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: DSearles on March 11, 2022, 10:10:39 AM

Title: Solved: low B+ voltage on Speedball large board
Post by: DSearles on March 11, 2022, 10:10:39 AM

Speedball large board low B+ solved: getting low voltage on B+ of 98vdc instead of 170-195. Also, one LED too bright, one unlit, 2 normal.

Read through the forum posts with great advice. Took 3 searches with a 10x magnifying loupe + flashlight, found a solder bridge on one of the tiny transistors, very hard to see, had to get the light right. And harder to remove, clearance too small for braid to absorb solder. Heated the leads and pulled the transistor up with a toothpick, worked perfectly. Resoldered the large transistors. Then all the voltages were correct, all LEDs lit at the same level, and the sound, wow! Am astonished at the Speedball improvement in creating present alive reproduction. Another upgrade that amazed me was the difference that replacing the Sennheiser pads made – was like a camera lens coming into focus.

Title: Re: Solved: low B+ voltage on Speedball large board
Post by: ng5921 on January 22, 2025, 12:27:17 PM

I had this exact issue after replacing all the components on my large speedball board!

Those pesky tiny transistor leads...


Thanks so much!