Federal AM-864

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MHanson

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That looks like every Federal AM-864 compressor I've had or seen.  It been thoroughly discussed here.  If you don't see the info you need on here, let me know and I'll dig up a scheme.  But I'm pretty sure it's all up here.

Michael
 

mushy

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Jan 20, 2008
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If you haven't already found it:  http://www.waltzingbear.com/Schematics/Misc/AM-864.htm
 

skal1

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Hi drpat

i got one of these the other day but the caps are missing of the turret board wat are the values of  your caps and material made of micra so onon.


skaL1
 

pucho812

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Pat those were military. I have heard that there were 2 versions. One was full frequency response, one was not.

Here is a link to the military manual. Note how it explains in detail everything from how to set it up, to how to destroy it so the enemy does not get their hands on it. Oh yeah it does have the schematic inside and a wiring diagram.

http://www.crossenstreams.com/federal_am864/Federal-AM-864-U-Manual.pdf
 

skal1

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just dwl this , it has no reference to the voltage or either the the type of capacitors it uses  on the turret board , could some shed a light on this....


thanks


skal1
 

skal1

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Thanks drpat  ,wima cap should easily work their right ?  yours looks a bit different to mine ,i think some ones do a rewire on that .

skal1
 

skal1

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Hey drpat

have you come across those types caps before , would be nice if i could get the originals in their.


skal1
 

skal1

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hey thanks for the link ,i need to pay more attention to things i thought that was a .1 uf also thanks for pointing that out . that c6 ,that one looks smaller than the rest hum...





skal1
 

emrr

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drpat said:
The only thing that I'm having a problem with right now is the meter. When in the ATT position, it displays 7db of gain reduction with no signal going to the unit. It deflects when I hear gain reduction happening, so I think it's just offset, as if -7 were "0". The OUT position may be off as well, but I haven't gotten too deep into checking that yet. I hope it's not a bad meter.

Since the meter reflects current draw in the input stage, it appears your current draw is low, or R2 is off in value.  Or R2 needs a new value.  Do you have known well performing 6SK7's?  If they are weak/dying, current through meter will be off. 
 

skal1

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Hey  drpat glad to  here your unit is working fine , i am still have a hum issue here is a link to my probelm , have you got any tips  on solving  the issue..


http://www.groupdiy.com/index.php?topic=34210.msg420931#msg420931


skal1
 

emrr

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I'd try some other tubes anyway.  I have seen several Gates SA-39's that would not adjust to 0 without a change in the parallel resistor, with all other possibilities eliminated first (voltages and current confirmed, resistances confirmed, various tubes tried).    -7 is probably too far down to apply to this idea, but is it possible to get inside the meter and zero the  mechanical trim?  Strange that they all have the mechanical zero posts, but no external access. 

In listening, be sure to do a full polarity swap on the unit for comparison, since the side chain detection is just a single side of the PP total.
 

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