The Dentron 10-160L is supposed to have 572Bs in it. How much high voltage?
73
Jim W7RY
--------------------------------------------------
From: "Tim Kass" <k8wbl@yahoo.com>
Sent: Friday, March 18, 2011 1:25 PM
To: <amps@contesting.com>
Subject: [Amps] Dentron amplifier problems
> Hello Group... I took over this project just recently when I purchased
> this amp from Ron, NR8O .. here is his original post...amp has apparently
> been sitting since that time..
>
>
> [AMPS] My dentron 160-10L
>
>
>
>
> from [Ron Rollinson]
> [Permanent Link][Original]
>
>
>
>
> To:
> <amps@contesting.com>
>
> Subject:
> [AMPS] My dentron 160-10L
>
> From:
> ronr@nowonder.com (Ron Rollinson)
>
> Date:
> Wed, 03 Mar 1999 01:04:50 -0500
>
>
>
>
> Hi folks, I've only been subscribed to the list for a couple of days but I
> can tell there is a lot of knowledge floating around here regarding amps.
> I don't know if it's related in any way to me subscribing to the list but
> the other day, there I was on 20 meters cw when my Dentron 160-10L
> (4-811a's) made a loud bang and popped the breaker in the back of the amp.
> When I opened it up I noticed one of the tubes appeared discolored and in
> the process of removing it the parasitic resistor in the plate line easily
> broke in half. One thing I noticed is that this particular resistor must
> have been replaced previously but a carbon resistor wasn't used, instead
> it
> looks like one of those metal film tv type resistors... Anyway, the
> damage
> is done, one tube is shot, and there appears to be a problem with the
> plate
> supply, I'm only getting about 1000 volts and a weird buzzing noise. I'm
> sure I can troubleshoot the plate supply and get it running again but
> while
> I've got the thing apart I'd really like to do some mods to it (Step start
> for one). Since I've seen very little disussed here about 811A amps I
> have
> several questions. Should I consider updating the parasitic suppression
> in
> the plate line (could this be what fried my amp to begin with)? Are there
> any other things I should consider doing such as grid current protection,
> high speed t/r switching, etc? I actually kind of like this amp but I've
> been unable to find anything in back issues of QST or on the net as far as
> mods or updates. Any advice or info on this amplifier would certainly be
> very much appreciated!
>
> 73, Ron NR8O
>
> I have since replaced the bad 811A, which likely shorted out...replaced
> the RF choke with a larger AL-572 choke and also a new harmonic supression
> board on top of the 811A's.. close fit..replaced the glitch resistor with
> a 10 ohm 10 watt variety... replaced the 1 amp diodes with 3 amp 1000 PIV
> jobies but still only getting 1000 VDC out.. brought up the amp slowly as
> well with a variac. There have been some mods to this amp as well.
> Someone replaced the meter switch with a 3 position switch and, according
> to Ron, was a by-pass switch. I removed the wire on this as to try to
> make this original to the original schematic and go from there. Now... at
> this point I think I have to consider checking and/ replacing the
> electrolytic caps... could some of them being open cause this low voltage
> situation or could it possibly be a problem with the primary transformer
> (heaven forbid) and costly.. Thanks for any input into this project.
>
> 73, Tim K8WBL
>
>
>
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