Re: Wicked intermittant Amplifone (Ampliphone) issue

I ran the game for a couple of hours last night with the screen bias down a touch, and we were fine. I'm going to elevate the screen to just above where I had it set originally and let it cook.

I'm glad that the degree of "warm" is normal. I have a fan on the back door that blows on the general area of both deflection, but was concerned about things getting maybe too warm.

----- Original Message -----
From: Cinelabs Info <cinelabs.info@gmail.com>
Date: Thursday, May 12, 2011 12:23 am
Subject: Re: VECTOR: Wicked intermittant Amplifone (Ampliphone) issue
To: vectorlist@vectorlist.org

> On Wed, May 11, 2011 at 2:28 PM, pj pj <pj1@shaw.ca> wrote:
>
> >
> > I was thinking warm like not lukewarm but warm like
> uncomfortably core
> > being heated by some inductive heating issue oversaturation warm.
> >
>
> From your description, it sounds normal. In operation, it's
> normal to get
> very warm to hot.
>
>
> > JR suggested running the heater off an isolation transformer,
> so I'll try
> > that at the same time using a separate adjustable supply that
> I can ease the
> > filament voltage up a bit to see if that will trigger the
> event (I had such
> > an issue back with a G07 on a really bad tube).
> >
>
> That's ok if you have an H-K short, which is the most likely if
> you have any
> short in the kine. You mentioned a short to a grid. Rodger can
> comment on
> how likely that is, but if that's what you have, depending on
> which grid it
> is, isolating the heater will raise all of the heater circuit to
> the grid's
> potential. If it happens to be the focus grid, it could get
> messy. Be
> careful.
>
>
> > The 3 focus block connections were redone when I overhauled
> the board,
> > wrapping the leads around the terminals. I used Ag/Sn/Cu
> solder I use for
> > high power RF joints on these specifically since I felt it
> couldn't hurt.
> >
>
> It never hurts to check. No need to re-terminate if you've
> already done it,
> but just pull the boots back for grins.
>
>
> > the deflection sensitivity was much higher, which likely meant
> that the HV
> > during the episode was probably way low.
> >
>
> That's logical. The question is, is it low because the (HV)
> power supply is
> putting out too low a voltage (bad PS), or is it low because the
> tube is
> drawing too much current from the supply (bad tube). The PS can
> only source
> a very small current, on the order of uA's, so it wouldn't take
> much to drag
> it down. The easiest way to check is measure the voltages,
> disconnect the
> anode and the kine and measure the voltages again.
>
> If you disconnect the kine, be sure to disconnect the anode.
> Legend has it
> that leaving the anode connected can damage the tube. Again,
> Rodger can
> editorialize.
>
> Your subject includes the word "intermittent". How often does
> this happen,
> and for how long?
>
> Still didn't catch your name.
>
> Thanks,
> -Mark
>

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Received on Thu May 12 19:38:06 2011