[R-390] Bad Tubes???

[Bill Hawkins]

Lessee, the radio worked 'good' or 'fine'. Sounds like a hamfest
description. The tubes are all 'bad'.

Can we get quantitative? Does the sensitivity meet specs? How
about IF gain? What about audio gain and distortion?

How bad is bad? What percentage of rated transconductance do you
get on the TV-7? Does a new tube test good? Are the pins corroded?
Does the heapkit test a new tube as good?

If you've got a 120 volt wattmeter, like the Kill-A-Watt unit, is
the power high for a 390? If you don't have a wattmeter, measure
the B+ voltages. Maybe the regulator failed high.

IIRC, there are at least 25 tubes in a 390. What tube functions
were OK?

Just the facts, sir.

Bill Hawkins, fan of Joe Friday


-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net] On Behalf Of Bob Camp
Sent: Thursday, June 21, 2007 6:31 AM
To: R-390 List
Subject: Re: [R-390] Bad Tubes???

Hi

One possible explanation - the tube tester you used a year ago was
broken.

I certainly have seen radios with a lot of "tests bad" tubes in them.  
If the radio is working fine, why replace them?

Bob

On Jun 21, 2007, at 2:51 AM, Joel Richey wrote:

> I read a lot of funny things on this list, this is one of the better 
> ones, 22 bad  ( really bad ) tubes but the radio still works good, did

> I miss something??
>
> Joe W2DBO
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