[BUILD] CAPI VP312DI~500/51x Series~Preamp + Direct Inject~Official Support Thread

[mkerlin]

I have a bad LED. Where can I pick up one that matches the CAPI's? Any particular specs for these?

Looking at other BOMs I think that these are the puppies:
https://www.digikey.com/en/products/detail/lumex-opto-components-inc/SSL-LX3044ID/270864

 

[jsteiger]

I have a bad LED. Where can I pick up one that matches the CAPI's? Any particular specs for these?

Looking at other BOMs I think that these are the puppies:
https://www.digikey.com/en/products/detail/lumex-opto-components-inc/SSL-LX3044ID/270864

Are you sure its bad and not backwards?

 

[mkerlin]

Are you sure its bad and not backwards?

100% sure. Wire from #1 was a little too long and shorted to the body of the 48V switch. Had a little spark action and then nothing worked right after. Pulled the LED and tested with DMM diode and didn't get 1600mV or dim light like the other working LEDs. Fixed the switch wire issue and then took an LED off one off my other working boards and installed it and everything is fine now. Just down one bad LED now.

 

[jsteiger]

100% sure. Wire from #1 was a little too long and shorted to the body of the 48V switch. Had a little spark action and then nothing worked right after. Pulled the LED and tested with DMM diode and didn't get 1600mV or dim light like the other working LEDs. Fixed the switch wire issue and then took an LED off one off my other working boards and installed it and everything is fine now. Just down one bad LED now.

Ah. I ASSume it was you who just placed a small order at the store and requested a 3mm LED?

 

[ltown2024]

Hello, I'm currently finishing up a vp312di kit I started over a month ago. I have a question about the 48v LED and troubleshooting to address a problem I may have detected by testing

1. Following the testing procedures on the old vp26 build guide, I measure with my DMM across the +V and C sockets and I read 10.18 Kohms. So I must diagnose the problem. But I'm honestly not sure where to start.


2. I'm confused on exactly how I should connect the red LED to the module. What I did in the photo seems intuitive to me, given the guides printed on the pcb.
but I see all sorts of different ways people have connected it. Especially with it changed over different revisions

 

[jsteiger]

10k is about right for a VP312DI with shunt jump set to cap coupled output so that is not an issue. The LED looks good to me in the pics.

 

[jpsguitars]

how do I ensure I have the correct hardware for my kit? from what I have seen from other kits, what I have is not the same.

 

[jsteiger]

how do I ensure I have the correct hardware for my kit? from what I have seen from other kits, what I have is not the same.

Did we email about this? This is right. Did you see the QR code attached to the L-bracket?
https://capi-gear.com/catalog/standoff-mod.php

 

[ltown2024]

10k is about right for a VP312DI with shunt jump set to cap coupled output so that is not an issue. The LED looks good to me in the pics.

Thank you for confirming that the LED is installed correctly.
It was actually me who requested that single red LED with an order. But funny enough, I screwed that one up too! So I then ordered 50 more from digikey haha

I should get the chance to troubleshoot my module this weekend, to find the problem causing me to read a lower resistance than expected between the +V and C Sockets (10kohm instead of 200kohm).

All I've done so far to try and solve it was cleaning up my solder work and insuring there were no bridges.
Before doing this I was reading only 3.5kohm.

Is it possible that my 10kohm reading is a symptom of an error on one of the relay boards?
I think I remember reading somewhere that the relay cards were a common cause for issues.

 

[jpsguitars]

Did we email about this? This is right. Did you see the QR code attached to the L-bracket?
https://capi-gear.com/catalog/standoff-mod.php

my bad. I didn't bother with the QR code due to the fact the ones I've scanned in the past just tried to sell me something else, obviously not the case here. thank you. also if you sent or replied to an email I did not get it so maybe I gave you the wrong email.

 

[jsteiger]

Thank you for confirming that the LED is installed correctly.
It was actually me who requested that single red LED with an order. But funny enough, I screwed that one up too! So I then ordered 50 more from digikey haha

I should get the chance to troubleshoot my module this weekend, to find the problem causing me to read a lower resistance than expected between the +V and C Sockets (10kohm instead of 200kohm).

All I've done so far to try and solve it was cleaning up my solder work and insuring there were no bridges.
Before doing this I was reading only 3.5kohm.

Is it possible that my 10kohm reading is a symptom of an error on one of the relay boards?
I think I remember reading somewhere that the relay cards were a common cause for issues.

You missed my reply...
https://groupdiy.com/threads/build-...ial-support-thread.40821/page-22#post-1158181

 

[krimo]

Hello!

I just finished 2 x VP312DI with DIY CA-0252 and Pikatron HiZ plugin (didn't try the FET-ZCON1's I also built yet). Everything is working ans sounding great except for one issue.

When I turn off the phantom power the LED on one of the two units, it takes very long to dim completely. I did accidentally put in a LED without resistor R16 briefly in one of the units and obviously it didn't survive that, but I'm not sure anymore which of the two units that was.

I replaced both LED's with (Capi) blue LED's of the same spec. They are a bit bright but working fine. R16 measures 10K on both units. Capacitor issue perhaps?

Best regards from the Netherlands,

Krimo

 

[jsteiger]

C12 the 100µF/63V cap drains thru the LED and 10k R when the phantom switch is turned off. If you have cables and mics connected this will also alter the time it takes to drain that cap. Depending on how you have the toggle wired, you can add a lead to ground on the unused pin that will drain that cap much quicker. That is what we do on all of the pre's with phantom on the pushbutton switches.