The most recent Eimac 8877 datasheet from CPII shows a 3-minute filament
warm-up time:
https://www.cpii.com/docs/datasheets/76/3CX1500A7-8877.pdf
The 07/01/1975 datasheet revision that Vic referenced shows 90 seconds:
https://frank.pocnet.net/sheets/140/8/8877.pdf
Typical operation of the Alpha 77 series amps is to step-start filament and
1/2 plate voltage together (approx. 2KV). Then after the warm-up period
completes, the operator may engage full HV at 4 KV.
Paul, W9AC
-----Original Message-----
From: Amps <amps-bounces@contesting.com> On Behalf Of Colin Lamb
Sent: Monday, January 23, 2023 4:06 PM
To: Fern Rivard <crc@cyberlink.ca>; amps@contesting.com
Subject: Re: [Amps] 8877 - HV with heater, or later?
I recall that Eimac said 90 seconds was ok for the 3cx800 tube. Then they
published a later publication that said 180 seconds was right. I think the
90 seconds was too short.
Colin K7FM
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