[TowerTalk] RE: [BULK] - [Amps] Soft 8877???

[Steve Katz]

Hi Paul, some comments below..... -WB2WIK/6

"Success is the ability to go from failure to failure with no loss of
enthusiasm." -Winston Churchill

> -----Original Message-----
> From:	Ash, Paul [SMTP:paul.ash at dmecorp.com]
> Sent:	Tuesday, October 07, 2003 9:18 AM
> To:	Steve Katz
> Subject:	RE: [BULK] - [Amps] Soft 8877???
> 
> Hi Steve,
> 
> No, I'm really not seeing a "dip".
> 
> //That's a bit odd.  For sure the pi-L in the Henry, when heavily loaded,
> doesn't show a very steep dip, but there is a dip nonetheless.  With
> lighter loading, it's more pronounced.
> 
> 
> Plate current seems pretty constant.
> 
> 
> //If it's 900mA at 4kV and only putting out less than 1 kW, an awful lot
> of power is being dissipated somewhere.  I would think if you left it
> key-down that way for several minutes, something would be very hot.
> 
> 
> The power output is pretty flat except
> if I mistune. I have not thought about
> a slipped drive chain!! Anything is possible
> at this point. HIHI. I will have to check that out.
> I somewhat doubt that is it though. 
> 
> //It's happened to me.  Actually, other things have happened with Henrys
> I've owned, including slipped camshaft (the cam that drives the plunger
> switches that switch padder caps in and out) and blown up padder caps,
> which usually leave "remnants" inside the floor of the RF deck.  When this
> happens, the amp usually still works and produces output, but it's never
> as much, as the tank resonates at a poor L-C ratio.  Did you open 'er up
> and look inside for broken stuff?
> 
> 
> I do seem to
> get the max power at near the settings that were
> listed in the hand generated "tunings" sheet
> that was originally provided by the factory.
> The original tests (with the lower voltage transformer
> that was in it) showed 1300W out on the CW setting
> (2100V on the plate) with the new transformer I
> am getting 3000V on CW and 4100V on SSB. That amp
> should be putting out 2200W on high power. Something
> somewhere is for sure eating up lots of power. But, the
> amp doesn't seem to be getting hot anywhere.
> 
> //The Henrys are very well cooled with big blowers.  It takes a while for
> things to get hot, but they will if you give it time.  Even the extremely
> robust 8877 will overheat when dissipating over 2000W for a period of
> time....  Check the switched padder (doorknob) caps, etc.
> 
> It has me stumped....
> 
> Paul
> 
> 
> -----Original Message-----
> From: Steve Katz [mailto:stevek at jmr.com]
> Sent: Tuesday, October 07, 2003 11:08 AM
> To: 'Paul Ash'; amps at contesting.com
> Subject: RE: [BULK] - [Amps] Soft 8877???
> 
> 
> Paul, does the plate current ever "dip" in approximate correlation to
> power
> output peak?  Is there any power output peak???  Your symptoms make me
> think
> something slipped in the bandswitch drive chain or camshaft, and the wrong
> components are in the tank (famous Henry problem)!  -WB2WIK/6
> 
> "Success is the ability to go from failure to failure with no loss of
> enthusiasm." -Winston Churchill
> 
> > -----Original Message-----
> > From:	Paul Ash [SMTP:bluesdude at cfl.rr.com]
> > Sent:	Monday, October 06, 2003 5:55 PM
> > To:	amps at contesting.com
> > Subject:	[BULK] - [Amps] Soft 8877???
> > 
> > Hello All,
> > 
> > A quick newbie question. 
> > I recently picked up an old Henry 3K X
> > that had sat unused for the last 17 years.
> > This is the version with the 8877.
> > This is my first 8877 based amp and I'm seeing
> > some odd behavior:
> > 
> > Max power out 700W. (from what I understand
> > I should be getting 3X that.)
> > Virtually no grid current.
> > Plate voltage looks ok, 4000V in SSB 3000V in CW mode. However, the
> output
> > does not change from one plate voltage to another. Just seems to hover
> > around 
> > 500-700W. I have tried driving it to 900mA on the plate
> > and 400mA on the plate, observed some difference but
> > not much, maybe 25% difference. 
> > 
> > Any ideas? At first I thought it might be the tuning circuits but I'm
> not
> > sure. Or, is it the tube? Seems to me that if I can pull 900mA through
> the
> > plate then the tube may not be bad...
> > 
> > 73,
> > 
> > Paul N1PA
> > 
> > 
> > 
> > _______________________________________________
> > Amps mailing list
> > Amps at contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps