speedball 1.1 in crack 1.0 issue

[Pohly]

Hey Guys!

I enjoyed my crack 1.0 (with 240V Bottlehead PT3) for a longer time (EVERYTHING WAS FINE) and decided to upgrade with speedball 1.1.

I assembled and installed after voltage check the small speedball circuit board and it worked fine providing more definition in the instruments (EVERYTHING WAS EVEN BETTER).

Now I assembled and installed  the large speedball circuit board. I measured the resistance of 12U vs. OB and OA and found that the resistance was not fix but was slowly increasing from some ohms up to very high, staying infinite.

As the resistance was now very high (near infinity) I proceeded with voltage check.The voltage at OB and OA howeverv was apparently higher than 100V. I disconnected the power cord and re-checked the resistance. Now the resistance of 12U vs. OB and OA was zero. I disconnected the large speedball circuit board and still am measuring at Terminal 7 and 9 (B3 and B6) zero ohms.

The large speedball circuit board looks okay, particularly the TIP-50 transistors and heatsinks are correctly installed. I even have measured the connections on the board which were okay.

What has happened and what to do next?

Thanks for your help!

[kgoss]

Post all your out of spec readings.  It will let the Bottlehead team give you the best and quickest support.

If I were you I’d clean the flux off the board before doing anything else. I ruined a board one time because I didn’t bother.  I was using Cardas solder and thought the flux was not conductive.  Maybe it’s not, but over time it did bad things to the board.  Needless to say I have always cleaned the flux off boards since then. 

[Pohly]

update

resistance measurements (without speedbal large circuit board)
terminal t1 infinite t2 5-14kohm t3 0 t4 10-14kohm t5 infinite t6 2kohm t7 500-1500kohm t8 0 t9 1500kohm-infinite t10 2kohm t14 9 t20 0 t22 0

(with speedbal large circuit board) OA 50-100kohm OB 50-100 kohm

is it a good idea to procedd with the voltage check?

[Paul Birkeland]

Here's the page from the manual, your resistance readings are consistent with what's written in the manual if you are reading 50K-100K.

If you are reading 0 ohms between terminal 12 and either OA or OB, then you have OA and/or OB wired to terminals 6 and 10 instead of 7 and 9, or you have not properly installed the heatsink mounting kit and the TIP50 metal bodies are touching the heatsinks.

[Deluk]

I thought that the SB 1.1 was just a revision that just made for an easier build by combining the two small boards on a large one. I still haven't built my version 1 yet. I think that this is the first time I've seen a comment that says there is also a sonic improvement. Anyone else like to comment?
Pic of large board shown has very blobby solder, probably twice as much as is needed, but if it works OK that's fine.