DIY Mic Pre Kits, Lunchbox Mic Preamp Kits, Power Supply Kits

Hello Ruel (and everybody else!!!)

I'm hoping I can get some help with this. I put together an 1848 kit with the 2U transformer and power kit last night. It powers up, no smoke, LEDS turn on, but I am getting very low voltage readings. I think there may be a problem with the transformer. This post says I should be getting at least 18VAC across AC1-CT and AC2-CT, and 36VAC across AC1-AC2. Here's what I'm getting:

(measured disconnected and connected to the pcb)
AC1 and CT=7.4VAC
AC1 and CT=7.3VAC
AC1 and AC2=15.7VAC

(measured with AC1-CT-AC2 connected to pcb)
48VDC and GND=17.9VDC to 18.5VDC (adjusting the trim low to high)
+ and GND=1.3VDC to 8.4VDC
- and GND=-1.2VDC to -8.3VDC

The transformer primaries are wired like this, secondaries are wired one set of blue/green tied together as CT and the other set as AC1 and AC2, per the build guide. I triple checked all components while populating and soldering the pcb. I've gone over all the joints and everything looks OK to me.

One thing I noticed is that the trafo gets very hot, I can hear the plastic kind of sizzle when I switch it on. Is that normal?

Thanks!

Jose

No that is not normal. Please disconnect and recheck everything.



Yes, this wiring guide is for 110V operation. Are you on 110V or 220V?





These are very low numbers. Less than 1/2 of what it should be.


Can you send me a good, clear, color photo of your build?

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Okay, I see you're in Long Beach, CA.... so you're 110V.

Send me a photo of your wiring guide so I can see if there's anything amiss.



That doesn't seem right.

PM or email me your name and address. I'll send you a replacement trafo. If you can, please send back the defective trafo so I can complain and send it back to my supplier!

Thanks!

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Email sent.

For the benefit of anybody reading this, here are some pictures of my build:
http://picasaweb.google.com/jose.franco/FiveFishPSU1848

Thanks!

I had the secondary side wired wrong!!!

It was wired like this.

I rewired it like this.

All voltages now measure correctly and the transformer is nice and cool.

Thanks for all your help Ruel!!!

I will include a wiring diagram on the instructions PDF to make it clearer which blue and green wire needs to be tied together.

Glad its working now.

PS: I don't need to send a replacement trafo.

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