[R-390] Fwd: tuning tool for Z503

[Alan Victor]

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---------- Forwarded message ----------
From: Alan Victor <amvictor at ncsu.edu>
Date: Sun, Oct 5, 2014 at 6:59 AM
Subject: Re: [R-390] tuning tool for Z503
To: Craig Heaton <hamfish at efn.org>


Thanks Craig and others for the heads up and good info. Yes, I have the Y2K
manual and Chucks video series as well as the Army TM. The Y2K Ch6 is clear
and a quality job. I was able to fashion a tool for Z503, the tune peak is
broad and not much improvement in AGC negative V at large signal
input. Another measurement on the Z of TP3 point of the AGC shows 380k-400k
ohm and the charge up shows AGC caps present but certainly not 500 k
plus ohms. So either a R is out of spec somewhere or the AGC caps, bypass
caps or both are leaky. One more measurement with the AGC feedback open and
controlled with an external supply should shed perhaps some light. I did
monitor the E208-E211 grid voltages while looking at the AGC V and they
tracked quite close. So I do not suspect an RF deck issue yet. The radio
is functional on all bands now, AM sounds great, and there is some AGC
action for sure. Just not quite enough to prevent overload particularly on
CW signals. In any case, after the IF deck is inspected and I am reasonably
happy with the electrical, I will then tear the whole radio down and begin
the clean process.

On Sat, Oct 4, 2014 at 5:44 PM, Craig Heaton <hamfish at efn.org> wrote:

>  These beast have been around for a while, maybe abused? With the IF deck
> out of the receiver, take all the covers off from the IF transformers. With
> a magnifying glass if necessary, look for wires touching things they should
> not. Z503 just has a single slug, and uses litz wire as a winding. I’ve
> found strands touching the cover on Z503. The other IF transformers will
> have resistors & caps inside. Make sure all is kosher.
>
>
>
> Just a suggestion: Follow the Y2K manual, chapter #6, almost to the
> paragraph as to what is next to adjust. There are a few items that can be
> looked at later, but not many. After getting the IF & RF in alignment, then
> go back and fix those pesky bugs. With the IF & RF peaked and adjusted per
> the manual, the other bugs are easier to find.
>
>
>
> Craig,
>
>
>
> *From:* Alan Victor [mailto:amvictor at ncsu.edu]
> *Sent:* Saturday, October 04, 2014 5:16 PM
>
> *To:* Craig Heaton
> *Subject:* Re: [R-390] tuning tool for Z503
>
>
>
> Hi Craig,
>
>
>
> Yes that makes sense. The transformer I am after right now is actually
> just a tunable L, namely Z503. Trying to double check an AGC issue and to
> be sure that I am not seeing a miss tuned plate load Z on the AGC IF amp.
> However, further measurements are pointing more towards a leaky cap or a
> grid bias way out of line due to major shift in grid resistor value(s).
> T503, 501,502 etc... I can see where I need to be able to tune primary and
> secondary independently.
>
> On Sat, Oct 4, 2014 at 4:24 PM, Craig Heaton <hamfish at efn.org> wrote:
>
> Alan,
>
>
>
> Went out to the shack for a look at my tool. Got it from Radio Shack years
> ago. I doubt they handle them today. As close as I can measure with a mike
> and converting to a fraction,  (0.095) 3/32 of an inch is about it. Do a
> search on Google and you might still have to place a phone call. It is
> important the shaft is smaller in diameter than the hex portion,  so both
> slugs can be adjusted independently of each other.
>
>
>
> Craig,
>
>
>
> *From:* Alan Victor [mailto:amvictor at ncsu.edu]
> *Sent:* Saturday, October 04, 2014 3:47 PM
> *To:* Craig Heaton
> *Subject:* Re: [R-390] tuning tool for Z503
>
>
>
> Wow, what a variety. Thanks for the link Craig!
>
>
>
> Alan
>
> On Sat, Oct 4, 2014 at 3:39 PM, Craig Heaton <hamfish at efn.org> wrote:
>
> Alan,
>
> Welcome to the golden age of vacuum toobs,,,,,,
>
> A quick Google search turned up several site which will gladly take your
> money. Here is a link to just one.
>
> http://www.amazon.com/s/?ie=UTF8&keywords=radio+alignment+tools&tag=googhydr
>
> -20&index=aps&hvadid=30006614487&hvpos=1t1&hvexid=&hvnetw=g&hvrand=762995914
> 6084527230&hvpone=&hvptwo=&hvqmt=e&hvdev=c&ref=pd_sl_2qvd2cheit_e
>
>
>
> Good luck & get'er fixed,
> Craig,
>
> -----Original Message-----
> From: R-390 [mailto:r-390-bounces at mailman.qth.net] On Behalf Of Alan
> Victor
> Sent: Friday, October 03, 2014 5:52 PM
> To: r-390 at mailman.qth.net
> Subject: [R-390] tuning tool for Z503
>
> Good day.
>
> Is there a part number/supplier for the hex tuning tool for the core in
> transformers like Z503?
>
> Thanks!
>
> Alan
>
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