Speedball Problems

[david luckenbach]

i am having issues with install of the speedball
crack was working fine prior to upgrade
9 pin leds not lighting up
voltages are 148, 155,0,170,145 across the board
resistors are fine

 

[Paul Birkeland]

Are both the 12AU7 and 6080 glowing?

 

[david luckenbach]

yes, they are both glowing  every so often i get a flash of white light from one of the tubes  not sure which one as the unit is upside down

also, now one of the 4 leds on the board is out.  looking at the board in mounted position-its the one at top right corner

 

[david luckenbach]

a9 connection was maybe bad as when i touched that green wire the two leds right side would flicker
i think i got  a better solder on that joint now.

but now one led is out as i mentioned above

 

[Paul Birkeland]

Has fixing that joint changed your voltages?  Can you post some build pics?

 

[david luckenbach]

hope the pics help
voltages today are slightly different  148, 173, 0, 170,  fluctuating
so the far right is going up and down
top right led still out
both tubes lit
9 pin leds still both out

 

[Paul Joppa]

The picture files seem to be empty.

 

[david luckenbach]

try these photos

 

[Paul Birkeland]

You have some substantial soldering issues that are going to cause some problems.  I would review this soldering video:

https://www.youtube.com/watch?v=EN16Pi7pcfk

Be sure you're not using lead free solder and also be sure your iron is turned up as hot as possible. 

Your joints specifically haven't been heated anywhere near long enough for the solder to flow out and work properly, and this is also true for the solder joints in the underlying build.  The exceptions to this (in other words joints to leave alone) would be the power switch and the solder joints for the LEDs, as they take substantially less heat to be properly soldered.

 

[david luckenbach]

so basically remove the circuit board and start over.....

 

[Paul Birkeland]

You can reflow all of the solder joints in the amp without removing anything.

 

[david luckenbach]

so i found some time to give this a go

voltages on 2,4,7,9, oa, ob and b+ are sill about half what they should be

resistance on 7 and 9, then b3 & b6 are not correct like they used to be

suggestions?

 

[Paul Birkeland]

The resistances on 7, 9, B3, and B6 won't be 3K unless you put the 3K resistors back in.

What's the DC voltage at 13?

 

[david luckenbach]

well whatever i did not was mess it up looking at dc voltage at 13
nothing lights up at all anymore, but i do get a flash when i plug in

 

[Paul Birkeland]

What flashes when you plug it in?  Is the fuse blown? What DC voltage do you measure at terminal 13?

 

[david luckenbach]

well yes i did blow the fuse..
so i replaced the fuse  and voltage at 13 was 5.5 dc
it didnt flash this time but now the 2 leds on the tube base stopped working

 

[Paul Birkeland]

If your voltage at 13 is 5.5V there is something very wrong with your amp.  Do both the 270 ohm 5W resistors look OK and unburned?

Did you carefully mount the TIP50 transistors as instructed in the manual?  If the hardware and insulating pads aren't put on properly, you'll end up with this exact situation.