Replacement power supply for a console

[firby]

Hi guys,

It's me. You might remember my last post about me squealing about my console being down. Then dissapearing when everyone pitched in to help. Sorry. It has been quite busy. Anyways, I pulled out a couple of other consoles and rerouted everything redid the channels that I needed and got going. Then I called a tech.

He came and put a fluke on the backplane of the console. One of the rails was reading about 5.1 volts. It is supposed to be 17 volts for this board which is a Trident 24. A Trident 24 is just a 24 buss Trident 65. Which is a nice board, which I need to get going again.

The tech was a good guy from a good tech company here in Cincinnati. He told me that I should get a replacement power supply for the board. He said that the new ones are much better than the old tech and that it wouldn't get as hot as the old one.

Has anyone here replaced the power supply for their board with an aftermarket ? I don't really know where to go and if there will be a qualitative difference between power supplies and the end sound. I am going to be hitting up people that know trident 65s and trident 24s personally to see if they have suffered this ailment with their boards.

I remember that there is a guy at great river that put two trident 65s together for a massive board in MIX magazine or something like that ?? Any help ? Anyways, I want to get a consensus opinion on how to do this right and understand what the costs are and what not.

So. If you are hearing this than please help.

I am seeing some accopian power supplies that look close but I want to hear what you say as well as what the tech says.

Regards. Peace.

[firby]

Oh sorry to double post. This board is big. It is a 72 slot Trident 65 currently loaded with 45 channels, master, aux, and 12 stereo group modules. There are five more modules (channels) that may or may not be deployed in the future. So, there is that.

I believe that it may be the largest Trident 24 in the world. Rawk on that.

Please help me get baby back.

[TapeOpLarry]

I'm not as sure about the Trident stuff, but I've mentioned before that some console's power supply units have a power up sequence built in, and if you ignore this you can fry some stuff. I know from experience... I would definitely ask around on this. I'll forward this link to Malcolm Toft and see if he weighs in.

[The Scum]

The power supplies that Trident shipped with the 65/24 weren't particularly good...at least the ones I've encountered. They run hot, don't have much spare current, and are a pain to repair.

I've built new supplies for two of that era Trident boards, a 18*4 65 and a 44*24 24. Both were composed out of a pile of Power One linear supplies, purchased on the cheap as Ebay surplus.

I honestly don't recall all of the voltages needed, but they each had something like 4 or 5 individual supplies, assembled in a handful of rack boxes. The little one got a single mid-sized +/- 15 V supply for the audio rails. The bigger one got audio rails composed of a pair of huge individual 24V supplies, which got tweaked down to 17V by changing the resistors in the reference network on the supply PCB - we had to find the datasheet for the IC in the supply to figure that out. The supply that became the -17 V was wired upside down - the usual output was grounded, and the supply then worked to make sure that the usual ground terminal sat 17 V below that.

Grounding is critical. With multiple supplies in multiple rack boxes, it takes some cleverness to avoid loops.

Take all of the usual precautions when dealing with AC off the wall.

Search the archives, I walked Honkyjonk through similar surgery a while ago.

We also swapped the meter bulbs for LEDs at thesame time...I made a bunch of assemblies with a resistor and 2 LEDs that we put in place of the original bulbs. Then we just used whatever supply we had handy (maybe a 12V) for them.

Larry's warning about supply powerup sequencing is prudent, but I've never had any problem with it on the 65. We ran the big Trident with just audio (and maybe logic...don't fully recall, other than the meters and LEDs were dark) rails for quite a while, while we got the rest of the supply voltages built.

[antoniosolo]

I am having a psu built for my Soundcraft by a tech formerly with Euphonix. I am sure he can build one for your console. I just found out he was able and willing to build mine for me and am sure he would do two simultaneously if you are still in need. Top notch tech who is nationally known.

[TapeOpLarry]

Malcolm Toft just dropped me a line on this. Looks like yer on the right track.

"Hi Larry,
Regarding the Trident 24 power supply replacement posts, I think these guys have got it covered pretty well. I have to admit that by to-day's standards, there was probably some room for improvement in the design. The suggestion of using Power One modules is actually pretty sensible. I have used these in the past and they have been very good. There are no issues with sequential power up and my golden rules with power supplies are simple:
1) Make sure there is at least 25 percent more current available in the supply than you actually need.
2) Make sure the ripple and noise is below 1 millivolt under full load for the audio rails.
3) Use a power supply that has short circuit protection.
The Power One (or similar) units should fulfil these criteria and the voltage is also adjustable on these.
I hope this helps.
Best regards,
Malcolm"

[djgout]

I've built several supplies for these desks and I have to agree the PowerOne, International Power, or Condor supplies are simply the best way to go. Especially if you go with one of the Linear ones , switching power supplies are okay, but I don't like them on my audio rails. If you wanna save a bit go with switching supplies for the logic/lamp/and phantom rails. And then go with Linears on the audio rails. I agree that the stiffer the supply the better, but a desk like that won't need anything like 9amp rails. With some creativity all of the supplies can fit into a 3U tall and like a 18" deep BUD case. Digikey or Mouser will have all the stuff. It should end up being around 450 or so for all the parts, so labor can get you up to around 6-750. Honestly it should take a tech about a day to mount and hook up everything.

-justin