#16
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The link works for me. Might want to try right clicking and choosing 'Save Link as'. Takes forever for my browser to open the PDF if I simply open the link.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#17
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Link akso works fine for me... but here is another resource from AK:
http://akdatabase.org/AKview/display...album=35&pos=0 jr |
#18
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Yeah it will let me navigate through the pages but the printed pages themselves aren't showing up in the PDF Download. So I'm not sure what's going on.
So I figured out that it must of been my Adobe Reader plugin on my web browser that was screwing things up because when I downloaded the file onto my computer and then opened it with Adobe Reader on my Computer it worked fine. Last edited by Captainclock; 05-13-2016 at 10:15 PM. |
#19
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Quote:
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#20
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So What's the modern substitute for this part? Is there an NTE Part that subs out for this part?
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Audiokarma |
#21
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Some members here may still have some epoxy ones in their parts bins, but you may have to substitute one of these metal ones: http://www.amazon.com/IC-AMP-8-LEAD-...productDetails . |
#22
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Am I missing something here? I don't see any ics in the schematic for the set... just 11 transistors
jr |
#23
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There are multiple version and revisions of the Twenty-One.
From the looks of his, it's probably one of the early (non-IC) versions. Pictures of the boards inside his unit could confirm this. . |
#24
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Interesting! thanks for the info... guess we need some chassis pix.
jr |
#25
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Here's some pictures of the insides of the unit.
First picture is of the tuner board, second picture is of the IF board, third picture is of the amplifier board. |
Audiokarma |
#26
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Since the IF board is shielded, I can't see if the active devices are transistors or ics.
But first things first, regardless of the type of device used for IF amplification, IMHO, the hum problem needs to be resolved before further problems can be addressed. jr |
#27
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Well if the filter capacitor wasn't the cause of the hum (it still hummed even after the filter capacitor was replaced) what else could cause the radio to have a 60 Hz hum?
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#28
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Post 9 jr tech mentioned the rectifiers. My thought too. You checked both of those?
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#29
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My first guess was on post 9 (bad power supply diodes), but there are additional filter caps on the audio board to check/ replace. Shorted output transistors could also place a hogh load on the power supply and cause hum.
Does the volume control change the loudness of the hum or is it always there? jr |
#30
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Is the hum still there when the volume is all the way down?
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Audiokarma |
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