andow said:On the Serpent site it says:
"SA-3A PCB’S WILL BE BACK IN STOCK ON MARCH 24th, 2017."
I was thinking about ordering but this makes me a feel unsure... ???
theposterkid said:I ordered (and received) three PCBs in the years after that date -- so I wouldn't put much stock in it. Clearly, they just don't realize or care that that statement is out of date.
I ordered another board last week, but have not heard anything from them. I'll check in today.
JMan said:Anyone care to enlighten me about the V+ rail? (See my question in the previous post)
theposterkid said:There's almost certainly someone else more knowledgeable than me to answer this, but I'll try. On the schematic, you have the toroid transformer, then the power switch, which goes to a bridge rectifier. The V+ is immediately after the bridge rectifier, but before the voltage regulators which supply the +35V and +28V rails accordingly.
JMan said:Thanks for the reply! I do see it on the schematic, after C10 on the way to the +28v. What I'm trying to figure out is what it's doing, and what voltage I should expect there, since the schematic gives no explicit indication.
I think that since my +35/+28/0v are good, the approx. +45v I saw at V+ is probably fine too. I could try to work it out using the schematic, but honestly, my basic EE math skills are rather subpar.
But like...I am just failing to understand what this is doing, and why we have a separate rail for it being sent over to the second board. I'm sure the answer is obvious, I am just missing it, and I'm curious.
In the meantime, I finished placing my caps this evening. Moving along bit by bit, looking forward to when she's done!
ComodoComplex said:Building this for a client right now so I thought I'd share my thoughts! From a quick skim of the schematic, sending the V+ over to the second board is basically unnecessary as it's not used by the second board. One could make an argument that it's best practice to do so, since sending the 35/28V rails without the V+ could cause issues if the regulators are populated on the second board... not sure why this would happen though. Those devices don't like to have voltage on their output and not on their input (they die).
The V+ rail I would call the unregulated supply - it'll vary with the AC voltage pretty much proportionately, though we usually expect to see 120V +/-10%. It's just there to provide a rough DC for the regulator chips to work with and supply the proper voltages to the rest of the compressor.
JMan said:Wow, great explanation! Thank you!
Neeno said:Hey guys, does anyone have a copy of the files for this project ?
The dropbox files aren't online anymore...
I tried to PM ruckus328 but his Inbox is full
Thank you for your help !
ComodoComplex said:Just finished up this project and it's working great! In the end, I found that running the V+ between boards using the power link *does* cause hum issues (120Hz)! Rather than disconnect C10 on the second board completely, I shielded this power wiring and that did the trick, though my shield had to be very tight. Ideally one would use proper shielded cable, but most people--myself included--only have 3-conductor cabling...
I tried uploading pictures to no avail. Might try again another day