Speedball big board voltages

[renz609]

Recently finished installing the Speedball kit and here are the voltages:

Small board:
OA: 78 V
1A: 189 V
B-A/B: 0 V
1B: 189 V
OB: 76 V

Big board:
OA: 121 V
OB: 104 V
B+: 186 V
G: 0

I checked the resistance previously and both OA and OB seem to be going over my multimeter's capacity. All the LED's are lit up as well.

OB seems to be within tolerances but OA is kind of high. Is this alright or would I have to troubleshoot it further?

Thanks.

 

[renz609]

By the way. I'm not sure if this is related but I there was a spark when I touched the capacitor lead on 9U with the soldering iron. It happened 2 more times when I touched it with the multimeter probe and then screwdriver after it's been unplugged for over half an hour. I haven't tried it with the other capacitor on 7U but is this normal?

 

[renz609]

Another thing I noticed when I tried it again after reflowing the TIP-50 legs and checking the voltages again to no avail, OA on the big board was still measuring at around 113 V even after the unit has been unplugged for about 5 mins. OB on the other hand is hovering around 1 V.

 

[kgoss]

Post some pictures of the wiring. Something is wrong because the voltage should bleed off the caps when the amp is turned off.

 

[renz609]

I measured the voltage again while it's been unplugged since my last post and OA is 9 V and OB is at 1.95 V.

Thanks.

 

[Paul Birkeland]

If you look at the TIP50 on the top side of the board in the A half, notice that the center leg looks like it pokes down into the solder, whereas the legs on other side have little solder cones going up the legs?  This is a visual clue that the TIP50 is not all the way soldered.

 

[renz609]

I resoldered those leads and measured the voltages again but the same problem still remains.

OA: 125 V
OB: 108 V
B+: 195 V
G: 0

Thanks.

 

[renz609]

I just re-soldered almost everything on the big board except for the LED's and my values are still hovering around the same.

OA: 122 V
OB: 106 V
B+: 187 V
G: 0

0A along with B6 are still measuring close to 115 V even after unplugging the unit.

Anything else I could try?

Thanks.

 

[renz609]

Anything at all? Is it usable in the least? I haven't tried listening to it yet since I installed the Speedball because I'm worried about my headphones.

Thanks.

 

[renz609]

Seems like I shorted the TIP50(sparks) while troubleshooting and half the LEDs on the big board have gone dark so I’m ordering some for replacement.

 

[Paul Birkeland]

In the last photo you posted, the center legs of the TIP50 transistors still don't look properly soldered.

-PB

 

[renz609]

Just thought I'd post an update to help out others with similar issues:

-I replaced the TIP50 & 2N2222 on the A side of the board but the 2 bottom LED's wouldn't light up.

-Used the diode mode on my multimeter and saw that the LED on D1 wouldn't light up unlike the one on the B-side so I ordered some replacement LED's.

-Replaced D1 at first which fixed that one but D2 was still dark. Replaced it as well and it seems to have fixed the issue with voltages at OA and OB hovering around 102 V.

Thanks