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Old 4th March 2013, 04:48 PM   #21
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No, just unsolder the two green transformer leads connected to T1-GRN.

What is the value of R3?
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Old 4th March 2013, 04:51 PM   #22
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Are you trying to check the value of R4 with a meter in-circuit? That usually doesn't work, as the current can be flowing all over the place. You need to have at least one end of the resistor disconnected.
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Old 4th March 2013, 04:52 PM   #23
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Quote:
Originally Posted by sagi4422 View Post
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?

I usually double check resistors with a multimeter before installing them,
especially when there's only the color bands on them.
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Old 4th March 2013, 05:29 PM   #24
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Quote:
Originally Posted by spendorite View Post
I usually double check resistors with a multimeter before installing them,
especially when there's only the color bands on them.
me too.......it's a good idea.
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Old 4th March 2013, 07:49 PM   #25
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Well I supposed if I buy from a known firm, I should not encounter such problems.
Tomorrow I will unsolder the resistors and the pins and check what you suggested
Thanks.
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Old 4th March 2013, 09:13 PM   #26
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Sagi: Your resistor values are probably correct. Measuring them in-circuit with a meter is a fruitless exercise. At least one end needs to be disconnected to measure with a meter.

R4 and R3 make up a resistive divider to elevate the heater voltage. If your B+ is say 400V, with R4 a 150K and R3 a 10K, the filament winding is elevated to 25V by being tied to the node between the R's (ohm's law voltage divider). The heaters/filaments still see 6.3V, it's just elevated from ground by around 25V. This reduces the potential between the cathodes and the heaters and means less hum/noise out to your speakers, and it is a little easier on the filaments in the tubes.

Please also let us know what you are using for a fuse, to eliminate other possibilities.
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Old 5th March 2013, 04:38 AM   #27
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The fuse I used is 3.15A/250V . It was something I found in my house. It was written as T3.15A/250V so I dont know if its slow-bow or fast
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Old 5th March 2013, 01:32 PM   #28
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Quote:
Originally Posted by sagi4422 View Post
The fuse I used is 3.15A/250V . It was something I found in my house. It was written as T3.15A/250V so I dont know if its slow-bow or fast
IIRC, the recommended fuse is a slow blow 1A-1.5A or so.

That's a little big.......don't go any larger or you'll risk damaging components.

If it's a fast blow, it will just have a metal filament. Slow blows have the filament wire wrapped around some kind of insulator.

The fuse on the top is a slow blow; the one on the bottom is a fast blow.

Do you still blow fuses if you unsolder the transformer filament leads?
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Old 5th March 2013, 02:07 PM   #29
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Sagi: What is your mains voltage? I have no idea what country you are in.....

If it's 240V, then a 3A fuse is too big.........it's marginal at 120V.
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Old 5th March 2013, 02:47 PM   #30
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What I have now are fast bo fuses. I am using 240V so I will buy lower amp fuses.
Anyway, should I wait to unpin the transformer-heater pins or is it possible to check it with the current fuses I have ?
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