I was starting to think maybe I put the crystals back in in reverse order,
but I couldn't have been that lucky :)
Ah, well, the T-4X is over in the corner for now and will require all my
tools to troubleshoot. I started on the first of the two R-4B's tonight,
have dismantled and washed it and it's now in the oven drying.
73,
Steve Wedge, W1ES/4
I swear by my life, and my love of it, that I will never live for the sake
of another man, nor ask another man to live for mine.
-Ayn Rand.
All my computers have my signature with various pearls of wisdom appended
thereto.
--------------------------------------------------
From: "Garey Barrell" <[email protected]>
Sent: Wednesday, November 30, 2011 9:35 AM
To: "Steve Wedge" <[email protected]>
Cc: "Drake List" <[email protected]>
Subject: Re: [Drakelist] T-4X: put on your thinking caps!
See below...
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Steve Wedge wrote:
Yes on the caps - absolutely! That particular chassis can is really easy
to sub modern caps under the chassis because the points they're wired to
are really easy to access.
Now here's a funny thing: on 40, I can peak the plate current with the RF
TUNE down below "1". This one is looking to be one of those rare ones
where I will actually have to measure the slug heights to get to a
starting point. Someone must have gone in sometime in the past trying to
peak it.
Sounds like either you have a coil failure or the slugs have been
misadjusted. Watch for a broken slug as well.
| The last trimmer to the back (which I believe peaks the driver) on 80
seems to need more capacitance, so looks like I'll have to be replacing
some fixed caps in there.
Yes, that sounds like perhaps another Dur-Mica failure! :-)
| Still scratching my head over why only 10m gives me a sidetone in either
CW or TUNE.
Probably a switching problem.
| I also hear the faint drone of the sidetone all the time if the gain is
advanced - just like in nearly every T-4X I've ever used (you have to
listen for it).
SIDETONE 'backwave' is usually high esr in C132, allowing the tone to
couple 'around' the keyswitch, D8, via the Plate supply for V9a and V9b.
D8 itself is also the problem sometimes, usually indicated by a junction
voltage increase (greater than -0.7 VDC) in receive.
Ah, well.
"We do this for fun ..."
There will be more time for this one later... 73, Steve, W1ES/4
-----Original Message-----
From: Garey Barrell<[email protected]>
Sent: Nov 29, 2011 10:10 PM
To: Steve Wedge<[email protected]>
Cc: Drake List<[email protected]>
Subject: Re: [Drakelist] T-4X: put on your thinking caps!
Steve -
Sure sounds like bandswitch. Don't forget to check bandswitch hardware
for wafer alignment, AND
check wafer center holes for oblong and not round holes!!
You DID disconnect the electrolytic caps from the old twist-lok when you
tacked in the tubulars....?
Verify the RF TUNE pointer is aligned properly.
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>
Steve Wedge wrote:
I have not taken out the scope or meter yet. Observations are somewhat
random.
My friend Keith's T-4X spent who knows how many years in a New
Hampshire cellar. Keith got it at
a hamfest long ago, from parts unknown. It was obvious to me that it
had belonged to a smoker and
was pretty grungy anyway, so it got the poolside view in my kitchen,
followed by the sauna.
I could "sort of" get output on 20m with it prior to its cleansing. It
was obvious by the fact
that it wouldn't work at all on CW that the can capacitor had dried
out. I replaced both caps
with modern units under the chassis. I had to sub an 80 uF for the 60
that was there because
that's what I had on hand.
I haven't tried it on all bands yet, but there's some weird stuff going
on here:
No output on 40& 15
60W is about all it can muster on 80& 20 despite tweaking the
trimmers. The rear 80m trimmer
needs to go in more but is against its stop
A couple of watts out on 10.
No sidetone - except on 10m. No real output on 10 (it's like 3 W).
There's a somewhat chirpy
sidetone on 10 only.
Neutralization must be way off, as max out on 20 doesn't match the dip.
I'm thinking the switch wafers need some Cramolin applied with a
toothpick (yes, I still have a
bottle of the stuff!).
The good news is that all the low-level stuff seems to be working as
far as frequency control.
All the tubes tested good on a TV-10 D/U except the finals which I
can't check on that tester.
Why would I only get any sort of sidetone on 10m?
Take your time, as I'll be setting this aside so that I can get to the
two R-4B's I have waiting
that I know I can clean, de-mod and align fairly quickly compared to
this sad rig. I was hoping
it was only going to be an alignment and a set of finals away from
finishing, but I'll have to
save this for later.
The R-4B's await - Keith told me no rush Smile emoticon
73,
I do suspect
Steve Wedge, W1ES/4
I swear by my life, and my love of it, that I will never live for the
sake of another man, nor ask
another man to live for mine.
-Ayn Rand.
All my computers have my signature with various pearls of wisdom
appended thereto.
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
