An illustrated guide to building an F5

I've just broken off one of the pins of my Schurter power entry module. Are you folks soldering hookup cable directly to these 3mm pins or using terminal clips? I'm having trouble finding terminal clips that would fit this, so I assume I'm missing something.

jovSo2y.jpg
 
I've just broken off one of the pins of my Schurter power entry module. Are you folks soldering hookup cable directly to these 3mm pins or using terminal clips? I'm having trouble finding terminal clips that would fit this, so I assume I'm missing something.

I soldered 14g solid core straight to it.

same here. only it was 16awg for me. Haven't found the correct size for the quick connect tabs.
 
after clipping the last lead on these MOSFETs if occurred to me that maybe they should not be touching the PCB because they produce so much heat.

It's small but there is physical (nonconductive) contact here. Can anyone confirm if I need to try again with new devices to get them farther from the board?

1W6tWHh.jpg
 
after clipping the last lead on these MOSFETs if occurred to me that maybe they should not be touching the PCB because they produce so much heat.

It's small but there is physical (nonconductive) contact here. Can anyone confirm if I need to try again with new devices to get them farther from the board?

That will be fine. The big resistors on the board are probably hotter than the mosfet case.
 
All of it is fine I think. Don't overthink it. You can save that power entry module by using the barrel of a crimp style eyelet of push on connector, cutting off just the barrel and using it as a splice between the wire and the tab. Crimp it down then solder it.
 

Attachments

  • Screen Shot 2021-10-11 at 11.25.03 AM.png
    Screen Shot 2021-10-11 at 11.25.03 AM.png
    205.6 KB · Views: 121
Hey folks me again. Thanks again in advance.

Here's my amp, its all wired up and looking pretty. I brought up the power supply on a variac and it measured +25v and -25 and made me feel like the deft success I'd always hoped to be. All of my LED's are wired the right way too, which always feels good.

zbOl86p.jpg


I'm having trouble getting the amp to bias. I'm measuring DC voltage across the 47r 3w resistors that are in the N and P channels. I carefully measured my trimpots and made sure that P1 + P2 were set to their minimum (0.5 ohms). A third voltmeter is across the speaker outs as per @ZenMod 's instructions in another thread.

mm5NBZG.jpg


I cannot get the voltage above the neighborhood of 50mV.

I had to remind myself that the V2 build guide is not 100% pertinent to the v3 board because parts numbers had changed. Once I figured that out, I was still befuddled.

So, here's where I am: no heat on the sinks, no burned or visibly damaged parts, hardly measuring above 50mV. What do I do?
 
Last edited:
Hey folks me again. Thanks again in advance.

Here's my amp, its all wired up and looking pretty. I brought up the power supply on a variac and it measured +25v and -25 and made me feel like the deft success I'd always hoped to be. All of my LED's are wired the right way too, which always feels good.



I'm having trouble getting the amp to bias. I'm measuring DC voltage across the 47r 3w resistors that are in the N and P channels. I carefully measured my trimpots and made sure that P1 + P2 were set to their minimum (0.5 ohms). A third voltmeter is across the speaker outs as per @ZenMod 's instructions in another thread.



I cannot get the voltage above the neighborhood of 50mV.

I had to remind myself that the V2 build guide is not 100% pertinent to the v3 board because parts numbers had changed. Once I figured that out, I was still befuddled.

So, here's where I am: no heat on the sinks, no burned or visibly damaged parts, hardly measuring above 50mV. What do I do?

F5 Bias Problem
 
I've maxed the trimpots out in the right channel and still not near where I need them to be. I'm tired tonight but I'll repeat testing both sides of the amp again tomorrow when I'm fresh.

I've read through the above thread, looks like it's worthwhile to adjust the resistor that's in parallel with the trimpots to 3k3. I can try that this week too.