JCM 800 build..... No Sound at all...

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Stevem
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Re: JCM 800 build..... No Sound at all...

Post by Stevem »

Something is very strange!
All of your secondary voltages are low but for the bias voltage.
I can only make two guesses here.
1) your PT is toast due to blowing the fuse so many times.
2) your PT has a 220 volt AC primary winding and your feeding that and not the 120 winding seing as your heater voltage are near half of what they should be.
3) are the center taps for your B+ and heater winding off the PT grounded?
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Jana
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Re: JCM 800 build..... No Sound at all...

Post by Jana »

I'm with tictac and rp--strip it down and try it again with some patience and forethought. What you have presently is a disaster waiting to happen.
What?
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rp
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Location: Italy

Re: JCM 800 build..... No Sound at all...

Post by rp »

Stevem wrote:Something is very strange! All of your secondary voltages are low but for the bias voltage. 2) your PT has a 220 volt AC primary winding and your feeding that and not the 120 winding seing as your heater voltage are near half of what they should be.
Imagine if he was in Europe and mis-wired the primary!
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ampgeek
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Joined: Sun Oct 15, 2006 1:31 am

Re: JCM 800 build..... No Sound at all...

Post by ampgeek »

Are heater voltages really half of expected?

It looks like he is getting ~3.4 VAC each from pins 4+5 and 9 to, presumably, ground.

Cheers,
Dave O.
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NickC
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Re: JCM 800 build..... No Sound at all...

Post by NickC »

ampgeek wrote:Are heater voltages really half of expected?

It looks like he is getting ~3.4 VAC each from pins 4+5 and 9 to, presumably, ground.

Cheers,
Dave O.
I would interpret that as 6.8VAC on the heater string.
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