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Old 4th March 2013, 03:18 PM   #11
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So.... (I think I need to change the topic) I powered it up today and nothing happened !
Actually something is happened. I blow up 2 fuses. It didnt hold 2 seconds before the fuses were burned.
Nothing was seen with the tubes, no light, no burn....nothing.
Moved the rectifier tube and the same went here.
How to continue from here ?

Thanks.
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Old 4th March 2013, 03:23 PM   #12
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Default Photos

Here some photos from the setup

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Old 4th March 2013, 03:27 PM   #13
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Quote:
Originally Posted by sagi4422 View Post
How to continue from here ?
Methodically.......

So, you are blowing fuses even with the rectifier removed?

Have you also installed the SS reectifiers? (the FREDs?) Do you have the SS/tube rectifier switch installed as well?

First thing to do is to triple check your resistors that you have not accidentally fitted say a 47 ohm R instead of a 47K ohm, etc. somewhere.

Last edited by boywonder; 4th March 2013 at 03:31 PM.
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Old 4th March 2013, 03:30 PM   #14
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Yep, It took 10 more seconds, but yes
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Old 4th March 2013, 03:33 PM   #15
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Quote:
Originally Posted by sagi4422 View Post
Yep, It took 10 more seconds, but yes
Sagi: I added more questions above .... Edited my post.

Have you also installed the SS reectifiers? (the FREDs?) Do you have the SS/tube rectifier switch installed as well?
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Old 4th March 2013, 03:40 PM   #16
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The FREDs are in (when I used the tube rectifier too). I didnt install the rectifier switch
So basically, when I powered it in the first time, the SS and the tube were in.
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Old 4th March 2013, 03:48 PM   #17
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Quote:
Originally Posted by sagi4422 View Post
The FREDs are in (when I used the tube rectifier too). I didnt install the rectifier switch
So basically, when I powered it in the first time, the SS and the tube were in.

Looking at the schematic, do you have a jumper across SW1-SW1? (where the switch would normally go) On the PCB, it's right where the various transformer leads connect.
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Old 4th March 2013, 04:06 PM   #18
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No. It was open (no wire/jumper connection) all the time
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Old 4th March 2013, 04:19 PM   #19
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Whatever you do, DO NOT install a higher amp rated fuse.....

Are your fuses slow blow or fast blow type? What current rating are they?

In your case, with no switch or jumper, you are using tube rectification. If you have a jumper or switch installed, you would be using SS rectification (when jumpered, or when the switch is closed) since the FREDs have much lower resistance than the tube, so all of the current would flow through them, even though they are wired in parallel.

Since it blows fuses with the rectifier out, you have a problem somewhere other than your B+ circuit.

If you unsolder the heater/filament leads from the transformer to the PCB, do you still blow the fuse with the tube rectifier not installed?

EDIT: Before trying the above, check that R3, R4 and C3 are the correct values.

Last edited by boywonder; 4th March 2013 at 04:25 PM.
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Old 4th March 2013, 04:41 PM   #20
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Quote:
Originally Posted by boywonder View Post
Whatever you do, DO NOT install a higher amp rated fuse.....

Are your fuses slow blow or fast blow type? What current rating are they?

In your case, with no switch or jumper, you are using tube rectification. If you have a jumper or switch installed, you would be using SS rectification (when jumpered, or when the switch is closed) since the FREDs have much lower resistance than the tube, so all of the current would flow through them, even though they are wired in parallel.

Since it blows fuses with the rectifier out, you have a problem somewhere other than your B+ circuit.

If you unsolder the heater/filament leads from the transformer to the PCB, do you still blow the fuse with the tube rectifier not installed?

EDIT: Before trying the above, check that R3, R4 and C3 are the correct values.
Do you mean unsolder the 9pin socket pins ?

Well, interesting thing here. I checked R4 and find out it is 80K (instead of 150K) it is strange as I checked the package it arrived for model and number (but didnt the actual resistance).It may be the problem?
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