{Collins} Re: 30L1 Resistors



Bryan....... the grid resistors can and do  act as "fuses" to protect the 
bias supply in the event of a plate to grid fault....... which can occur. 
Also R-17 and R-18  serve that purpose as well......... when a fault occurs, 
they "disappear!

To replace them with higher wattage resistors will change the "time-current 
curve" and reduce the protection to the power transformer and can possibly 
cause damage.

 I would stick with the proper resistors,,,,,,, they have been available 
here on the CCA net from time to time.

There is as mod whereby one can add a 130V MOV across C-2 to the 
chassis/ground which will give some protection in that event.

The 811's do fail that way occasionally.

It would be unwise, in my opinion to risk it.

GL/73/jim/W0JJL

----- Original Message ----- 
From: "Brian Roberts" <k9vky@xxxxxxxxxxx>
To: <collins@xxxxxxxxxxxxx>
Sent: Saturday, November 19, 2005 7:13 PM
Subject: {Collins} 30L1 Resistors


> Hello Gents--
> How critical are the 47 ohm 1 watt resistors (R21-24) to the 811A grids on 
> the 30L1 amplifier?  Can 52 ohm 2 watt resistors be used or must they 
> exact replacements?  Thanks.  Brian K9VKY
> Sponsored by the Collins Collectors Association 
> http://www.collinsradio.org
> Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
> Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
> 1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
> Sun AM Net: 29.050 Mc-1200 Central
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Sponsored by the Collins Collectors Association http://www.collinsradio.org
Nets: Tues: 3.805 Mc-2000 Central / Thur: 3.875 Mc-2000 Central
Fri: 3.895 Mc-2000 Pacific / Sun: 14.263 Mc-2000 UTC
1st Wed (of the month) AM Net 3.880 Mc-2000 local (ET, CT, MT, PT)
Sun AM Net: 29.050 Mc-1200 Central






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