Issue with Crack Voltage [solved]

[Paul Birkeland]

Yes, I bet if you pull the 6080, those voltages will pop up.

Are your TIP50's properly isolated from the heatsink with the supplied hardware?

[lwhitit]

Yes, I bet if you pull the 6080, those voltages will pop up.

Are your TIP50's properly isolated from the heatsink with the supplied hardware?

I will check it out tonight to test. I reviewed the instructions and I did place the thermal pad (was different from instruction pic, clearish plastic looking sheet) in between the heatsinks and the tip50's. Also the fibre washer was used for each.

[lwhitit]

Terminal Voltage (6080 removed) Plus pictures of both TIP50's and heatsinks.
1 75-90 (79)
2 170 (222)
3 0 (0)
4 170 (222)
5 75-90 (81)
6 0
7 100 (1)
8 0
9 100 (0)
10 0
11 0
12 0
13 170 (222)
14 0
15 185 (228)
20 0
21 206 (233)

[Paul Birkeland]

Yeah, that indicates that there's either a short on the board, or the TIP50's are touching the heatsinks.

-PB

[lwhitit]

Yeah, that indicates that there's either a short on the board, or the TIP50's are touching the heatsinks.

-PB

I am not sure what to do next. Are the pics good enough to confirm if I did it correctly? If so what should I start to check on the board.

[Paul Birkeland]

Check the resistance between the metal tab of each TIP-50 and the screw.

-PB

[lwhitit]

Check the resistance between the metal tab of each TIP-50 and the screw.

-PB

I checked it out and both look good. I get a 1 (no reading) when I check both metal tabs (silver) of the tip-50's and the connected screws.

[Paul Birkeland]

Well, we know that the 6080 is functional, as you did pass the voltage tests with the stock circuit.  Now that you have the small PC boards working, that only leaves issues with the large PC board.  I would suspect that some adjacent pins are soldered together, causing the short that is dragging your voltages down.

[lwhitit]

Well, we know that the 6080 is functional, as you did pass the voltage tests with the stock circuit.  Now that you have the small PC boards working, that only leaves issues with the large PC board.  I would suspect that some adjacent pins are soldered together, causing the short that is dragging your voltages down.

Ok that gives me an idea what to look for. I will check out my soldiering on the big board and report back.

Thanks!

[lwhitit]

I took it apart again and redid all the connections on the big board. Powered it up and all 4 leds were lit! I can finally leave you alone. Its up and operational and everything sounds good so far.

Thanks again PB