Speedball voltage problem and LED not lit [resolved]

[henmyr]

Hi.
I've assembled and attached the speedball upgrade but are having problems with it.

First the locations of the boards:
When the amp is upside down, the word Top on the big bord is away from me.
The board A is to the left and B to the right.
(Both tubes are inserted)

The behaviour:
The headphone left channel doesn't seem to have a problem, but the right side doesn't have sound (or maybe very little, don't dare to try again just yet).

When I turn on the amp, all the voltages are within specifications and the leds look fine. Then after about 15-30 seconds, the voltages and leds starts to missbehave like this:
The led D1 is very bright and sometimes flicker.
The led D2 is not lit (or very weak).
The led between pin 8 and center (12AU7 tube socket) is very bright and sometimes flicker.

These are my voltages:
AO and an O on the large board looks very bad.

A   Should be       actual
I   170-185       163
O   75-90       161
B      
I   170-185      163
O   75-90      75
      
Large PCB      
b+ above A   170-185   164
O above A           90-100   158
b+ above B   170-185   164
O above B    90-100   101

I've reflowed all joints twice.

 Any Idea where I should look for errors?

[Paul Birkeland]

Please refrain from listening to an amplifier that does not pass its voltage checks, as you may damage your headphones.

A very bright LED on the 9 pin socket and very high voltage at an "O" terminal would typically be caused by R1 being the wrong value on the small PC board.

Having said that, we redid the entire Speedball kit and made R1 visually unique to eliminate the possibility of this error.

The other likely cause is that you have a solder blob on the bottom side of the small PC board that is allowing for excessive current flow.

The voltage irregularity on the big PCB will resolve itself once you fix what's going on with the small board.

Just to be sure, can you perform the Small Board Voltage Check on page 18 with no 6080 installed and let us know what voltages you get?  (You can leave the amp on like this for a minute to verify that the problem persists)

[henmyr]

Please refrain from listening to an amplifier that does not pass its voltage checks, as you may damage your headphones.

A very bright LED on the 9 pin socket and very high voltage at an "O" terminal would typically be caused by R1 being the wrong value on the small PC board.

Having said that, we redid the entire Speedball kit and made R1 visually unique to eliminate the possibility of this error.

The other likely cause is that you have a solder blob on the bottom side of the small PC board that is allowing for excessive current flow.

The voltage irregularity on the big PCB will resolve itself once you fix what's going on with the small board.

Just to be sure, can you perform the Small Board Voltage Check on page 18 with no 6080 installed and let us know what voltages you get?  (You can leave the amp on like this for a minute to verify that the problem persists)

Hi and thanks for the reply!

I started to write on my reply and while looking for blobs, I instead found a wet glare of solder flux on the top side of a board (I had already cleaned the bottom). I cleaned the boards using isopropyl alcohol and a tooth brush and now all measurements are good and no problem at all using headphones:)

One thing though:
Page 18 in my Speedball manual begins with "Assembly, Part Two - Demolition and Installation".
I don't have any voltage checks for the small boards alone. Is there a newer version of the manual available?

[fullheadofnothing]

The manual for the new version of the Speedball is not compatible with the old version of the kit.

It was unclear in your original post which version you owned, hence the confusion.