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Bottlehead Kits => Crack => Topic started by: Love Rhino on June 01, 2020, 08:46:47 PM

Title: Large board speedball high voltage [resolved]
Post by: Love Rhino on June 01, 2020, 08:46:47 PM

Good morning!

I installed the small speedball board onto a working crack, and it passed its checks:
oa: 77.6
ia: 174
b-a/b: 0v
ib: 175
ob: 75

Today I installed the large speedball board, and one of the led's (the closest to the headphone jack) is not lit.  Voltage checks are high:

OA: 143, dropped to 130
OB: 115
G: 0v
B+: 205

Any specific area that jumps out that I should look at first?

Thank you!  Let me know if pictures would help.

-Denver

Title: Re: Large board speedball high voltage
Post by: Paul Birkeland on June 02, 2020, 05:24:37 AM

I would flip that big PC board over and give it a good once over on the solder joints.  You probably don't need to reheat the joints on the LEDs, as those solder very easily, but everything else could get a reheat on the solder.  It may help to post some pictures of the board too. 

For the TIP50 transistors in particular, 5-10 seconds of soldering iron heat per leg isn't unreasonable.

Title: Re: Large board speedball high voltage
Post by: Love Rhino on June 02, 2020, 06:48:00 AM

Thanks so much for your quick response!

I reflowed some joints, especially the ones you mentioned.  I am getting lower readings but still a bit over what we're looking for.  Enough to keep working or is this fine?

Large board:
OA: 104
OB: 104
G:0
B+: 176

Thanks for everything!

Title: Re: Large board speedball high voltage
Post by: Paul Birkeland on June 02, 2020, 06:52:21 AM

Those are good readings!

-PB

Title: Re: Large board speedball high voltage
Post by: Love Rhino on June 02, 2020, 07:36:53 AM

Great!  I'll bolt everything down and give it a listen tonight.  I forgot to mention that all the leds light now.

Thanks again :)