POWER PLANT BUILD THREAD

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Jonk
Posts: 9
Joined: Thu Oct 01, 2009 2:50 am

Re: POWER PLANT BUILD THREAD

Post by Jonk »

Hi,

I have a power plant here that was blowing fuses (unloaded so I know it's the power plant) I replaced the 110/220 switch and it stopped blowing fuses but I couldn't adjust the regulators for 24 and 48V's They only go up to 17VDC and 35VDC respectively. I tried replacing the regulators to see if they were the problem but no change. And the power transformer is getting very hot.

Any ideas what's going on here?

Jonk
Posts: 9
Joined: Thu Oct 01, 2009 2:50 am

Re: POWER PLANT BUILD THREAD

Post by Jonk »

This can't be right. I have 51VAC, 54VAC, 56VAC, 62VAC on the power transformer secondaries. ??? Maybe I hard wired the pirmaries wrong. Okay, it's a DPDT slide switch so I hardwired the side that says 110V. I don't get it. . .

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Joe Malone
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Re: POWER PLANT BUILD THREAD

Post by Joe Malone »

Jonk wrote:
Mon Sep 06, 2021 5:39 am
This can't be right. I have 51VAC, 54VAC, 56VAC, 62VAC on the power transformer secondaries. ??? Maybe I hard wired the pirmaries wrong. Okay, it's a DPDT slide switch so I hardwired the side that says 110V. I don't get it. . .
The 115v / 230v switch overlay shows the correct way to fit the switch which should be fitted but if you do not fit the switch since it is a slide switch that shows the voltage when slide the opposite way you would have to jumper the opposite side to the voltage written on the pcb. But I cannot see how either way you could get that winding voltage unless something is built wrong. Remove the 2 silicon tubes and send me some top and bottom photos of your kit build so I can check it over.
Joe :-)
JLM Audio
Capturing Audio without Injury

Jonk
Posts: 9
Joined: Thu Oct 01, 2009 2:50 am

Re: POWER PLANT BUILD THREAD

Post by Jonk »

Thanks Joe,

Here's some pics. This was a successful build, calibrated correctly and powering four Neve 1290 cards for about 6 months. Then one day I powered it on and the fuse blew.

So I suspected that slide switch.

So, if I get you right, the correct pads to jumper for 115V would actually be on the 230V side, according to the pcb. Interesting. So I was getting the voltages on the secondaries mentioned in the earlier post while accidentally connecting the primaries for 230V. Now connecting the primaries correctly I'm back to blowing fuses again upon power up.
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Joe Malone
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Re: POWER PLANT BUILD THREAD

Post by Joe Malone »

Jonk wrote:
Tue Sep 07, 2021 2:29 am
Thanks Joe,

Here's some pics. This was a successful build, calibrated correctly and powering four Neve 1290 cards for about 6 months. Then one day I powered it on and the fuse blew.

So I suspected that slide switch.

So, if I get you right, the correct pads to jumper for 115V would actually be on the 230V side, according to the pcb. Interesting. So I was getting the voltages on the secondaries mentioned in the earlier post while accidentally connecting the primaries for 230V. Now connecting the primaries correctly I'm back to blowing fuses again upon power up.
Sounds like a dead short on one primary winding. Remove power and remove the 2 110v jumper wires and check the ohms on each 115v primary winding which should be about 80ohms each from memory. Check there is no solder short under the pcb at the high volts end. let me know what you find.

If the ac volts on the secondary was actually the volts you mention the 1000uF caps would all have blown their tops.
Joe :-)
JLM Audio
Capturing Audio without Injury

Jonk
Posts: 9
Joined: Thu Oct 01, 2009 2:50 am

Re: POWER PLANT BUILD THREAD

Post by Jonk »

Okay,

back with some ohm readings. Sounds like you're right (I think?) One primary reads 16ohm. The other is 91ohm.

Jonk
Posts: 9
Joined: Thu Oct 01, 2009 2:50 am

Re: POWER PLANT BUILD THREAD

Post by Jonk »

So, what would you expect to need to be replaced besides the power transformer? Caps as well? Not seeing them puffing out though.

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Joe Malone
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Re: POWER PLANT BUILD THREAD

Post by Joe Malone »

Jonk wrote:
Thu Sep 09, 2021 5:57 am
So, what would you expect to need to be replaced besides the power transformer? Caps as well? Not seeing them puffing out though.
HI Jonk
It should only need a new transformer as the caps look fine. Email me to so i can quote price for one with shipping for you.
Joe :-)
JLM Audio
Capturing Audio without Injury

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