power transformer bad?

[TarheelTechinTraining]

I apologize for having posted in the wrong place. I'm debugging my first build, a jcm800. My question is should it take a minute or two for the voltage to reach 500 Vdc. This is after rectifier but before stand-by. Going through 100uf capacitor before stanf-by. Thanks for the help, Greg

[Leo_Gnardo]

I'm debugging my first build, a jcm800. My question is should it take a minute or two for the voltage to reach 500 Vdc. This is after rectifier but before stand-by. Going through 100uf capacitor before stanf-by. Thanks for the help, Greg

Very curious that it would take a minute or two to come up to full voltage, it's usually more or less instant, under a second. You don't have a lightbulb current limiter on the AC line? That or something like it would result in a slow chargeup.

[TarheelTechinTraining]

Nope. Just the rectifier and the cap

[TarheelTechinTraining]

Plus when I take it off stand-by the voltage drops unless the 50uf caps are disconnected

[The Dude]

Measuring the AC on the transformer secondary, how long does it take to reach it's max output?

[TarheelTechinTraining]

382 vac instantly

[The Dude]

Then it can hardly be a bad transformer. Can you show or draw up a quick schematic of how you have the circuit wired?

[Jazz P Bass]

Caps in backwards.

[TarheelTechinTraining]

Pretty sure its correct. The schematic I'm using is a 2204 by Marc huss. Only difference between it and mine is stand-by placement. Mine is between cap and fuse. Schematic between transformer and rectifier

[TarheelTechinTraining]

Could switch placement be the answer?

[The Dude]

Possibly a grounding issue? Do the caps and the PT center taps share a ground as shown in the schematic? Also can you verify this is the schematic you are working from?

http://mhuss.com/MyJCM/JCM800_2204.pdf

[TarheelTechinTraining]

Yep that's it.

[TarheelTechinTraining]

No the caps and pt don't share a ground

[g1]

Are they both grounded?

[The Dude]

Are they both grounded?

Yes, that's what I was asking. I meant electrically- not physically. I was surmising that maybe the voltage was 'floating' up because of a missing ground and that's why it took so long to get there.