Low cost source for 6146W

[Glen Zook]

RCA announced the 6146B/8298A during the first half of 1964 and originally stated that it was completely compatible with the 6146 and 6146A/8298.  Therefore, the military changed the contracts for the 6146W from the 6146A/8298 to the 6146B/8298A during the latter half of 1964.  Unfortunately, there was no change in the nomenclature which told if the 6146W was the equivalent of the 6146A/8298 or the 6146B/8298A.  This completely compatible statement did not prove to be true and the military found this out when the later 6146W tubes were used in equipment designed for the earlier versions.

The changes to production generally happened in the last half of 1964 but there was no "drop dead" date and therefore each tube manufacturer made the production change at various times.  As such, any 6146W with a code date of June 1964 or before is going to be the 6146A/8298 equivalent and any 6146W with a code date of January 1965 or later is going to be the 6146B/8298A equivalent.  However, a 6146W with a code date of between July 1964 and December 1964 could be either version and that is where the problems come in.  Fortunately, 6146W tubes that are usually found today have code dates of well after 1964 so there is no problem with knowing which type they actually are.

Most, but not all, of the equipment designed to use the earlier versions of the 6146 family are generally "unhappy" with the 6146B/8298A.  I have worked on like 3 versions of exactly the same model of transmitter with serial numbers within 10 of each other.  Of these 1 was perfectly "happy" with the 6146B/8298A and the other 2 would not operate properly.  Although I don't know exactly why this difference, I suspect that it has a lot to do with component tolerances and that the example wherein the later version worked that these tolerances just "happened" to "add up" in a manner that allowed them to work.

I know that there are those who say that they have been able to use the 6146B/8298A without any problems and I definitely believe them.  However, the majority of transmitters designed for the earlier versions are problematic when using the later version.

Glen, K9STH

Website:  http://k9sth.com


--- On Mon, 2/16/09, kd4e <doc at KD4E.COM> wrote:

> From: kd4e <doc at KD4E.COM>
> Subject: Re: [HEATH-TEMPE] Low cost source for 6146W
> To: HEATH at LISTS.TEMPE.GOV
> Date: Monday, February 16, 2009, 8:09 AM
> If you do a http://clusty.com search on Heath and 6146W I
> would expect
> that you'd get several hits as there have been a number
> of articles and
> discussions about this.
> 
> It is not that a 6146W will not work, it is just that the
> circuit components
> are not designed for them, you have to tweak the values and
> most Hams
> don't see the value added to do all of that.
> 
> There are tons of 6146's that are plug & play out
> there for $8.-$10. each,
> 
> 
> > Darryl Jones wrote:
> > What's the rule of thumb for date codes on
> 6146W's?
> > How does one know it's B vs A? I've always
> stayed away from W's as I bought
> > a pair and couldn't get them
> > working right in my old Heath.
> > 
> -- 
> Thanks! & 73, doc, KD4E



      

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