[BUILD] CAPI VP28~500 Series~2-Stage Preamp~Official Support Thread

[jsteiger]

Thanks for the reply

Readings:
1-3 62.0
2-4 68.9
5-6 1.567
1 to can OL
2 to can OL
3 to can OL
4 to can OL
5 to can OL
6 to can OL
7 to can 0.6
8 to can OL

Jeff says this fully checks out. Transformer orientation was correct. I can’t explain it other than to say it didn’t work in two different preamps but the one I swapped from a working preamp did. I’m an engineer and I don’t believe in coincidences, and for me to solder it bad twice I wouldn't have thought likely, but I can't exclude it.

Jeff was nice enough to get a replacement off to me. I'll send him this one and see how he makes out with it.

Wait a second. I guess I read your email too fast. The secondary winding and DCR should be between pins 5 and 8 not 5 and 6. Pin 6 is the internal screen and gets grounded. If pin 5 has continuity to pin 6 then that is indeed the issue.

 

[mkerlin]

Wait a second. I guess I read your email too fast. The secondary winding and DCR should be between pins 5 and 8 not 5 and 6. Pin 6 is the internal screen and gets grounded. If pin 5 has continuity to pin 6 then that is indeed the issue.

Sorry Jeff, my typo. The 6 should have been 8. 5-8 was 1.567. Pin 6 to can is OL.

 

[Volume11]

Does anyone know the wire color coordination for the transformers on the most recent kits? I have pink, purple, and grey, instead of blue, brown, and green.

Thanks

 

[jsteiger]

Does anyone know the wire color coordination for the transformers on the most recent kits? I have pink, purple, and grey, instead of blue, brown, and green.

Thanks

The links you'll need are in the first few lines of info here https://capi-gear.com/catalog/product_info.php?cPath=22_117_55_169&products_id=478

 

[Volume11]

The links you'll need are in the first few lines of info here https://capi-gear.com/catalog/product_info.php?cPath=22_117_55_169&products_id=478

Thanks Jeff, I guess I looked everywhere but the most obvious place, my bad.

 

[woofy]

I built two vp28s, no issues for a week or so, however now the yellow polarity LED is getting stuck always lit. Sometimes when i power down for a while and back on, the issue resolves until the unit is heated up a little bit. Any advice appreciated

 

[jsteiger]

I built two vp28s, no issues for a week or so, however now the yellow polarity LED is getting stuck always lit. Sometimes when i power down for a while and back on, the issue resolves until the unit is heated up a little bit. Any advice appreciated

Try exercising the switch a bunch. Might be a faulty pushbutton switch or needs some deoxit. Also make sure the LED's leads do not extend past the solder pads.