[Amps] AL-1500 'thump'
Aleksandar Petkovic
vk6apk at bigpond.com
Wed Feb 18 17:32:59 EST 2026
Yes. That's correct. I have bought quite a few items through his website
and Tom has also provided valuable technical help at times.
73, Alek VK6APK.
On 18/02/2026 10:30 am, David Gow wrote:
> He is the original designer of the Amertron amps.
>
> On Tue, Feb 17, 2026 at 2:38 PM Aleksandar Petkovic via Amps
> <amps at contesting.com> wrote:
>
> Thanks mate.
>
> 73, Alek VK6APK.
>
> On 18/02/2026 1:00 am, maflukey at gmail.com wrote:
> > His ebay store is "W8JI CTR Engineering All Things Ham"
> >
> https://www.ebay.com/str/w8jictrengineeringallthingsham?_trksid=p4429486.m3561.l161211
> >
> > Matt
> > KM5VI
> >
> >
> > -----Original Message-----
> > From: Amps <amps-bounces at contesting.com> On Behalf Of Aleksandar
> Petkovic via Amps
> > Sent: Monday, February 16, 2026 10:42 PM
> > To: amps at contesting.com
> > Subject: Re: [Amps] AL-1500 'thump'
> >
> > I wasn't aware of his ebay store. Can you provide a link please?
> >
> > Yes, I have his filter board and the EBM Papst blower in my
> AL-1500, but I bought them directly from him. I would like to see
> the ebay store.
> >
> > 73, Alek VK6APK
> >
> > On 17/02/2026 12:07 pm, maflukey at gmail.com wrote:
> >> FYI, W8JI sells upgraded HD capacitor boards, upgraded HD
> rectifier boards, and upgraded soft start boards for the big box
> Ameritrons on his ebay site. IMO they are very well designed,
> assembled, tested high quality boards that I seem to recall Tom
> describing as the boards that would have gone into the AL-1500 had
> production costs not needed to be considered. The boards have
> several improvements from the originals and are relatively easy to
> install.
> >>
> >>
> >>
> >> Matt
> >>
> >> KM5VI
> >>
> >>
> >>
> >> From: Rejean Leveille <rejva2am at gmail.com>
> >> Sent: Monday, February 16, 2026 2:42 PM
> >> To: maflukey at gmail.com
> >> Cc: Steve Bookout, NR4M <steve at nr4m.com>; amps at contesting.com
> >> Subject: Re: [Amps] AL-1500 'thump'
> >>
> >>
> >>
> >> Hi
> >>
> >> In the past my soft start relay got defective, also with age it
> may not read the right high voltage, easy fix be replacing the
> Mohm resistance..
> >>
> >> Also if the HV was near 3600 volts, there is no safety
> electrolytic margin at 450 volts. All equalizer resistors need to
> be very close values. If their color doesn't look like new then
> replace them all by ordering twice (16x). to pick up the 8x match.
> >>
> >> Unless you have some safety experience measuring each
> electrolyte DC
> >> voltage then do not do it. The diode pcb needs to be vertically
> locked
> >> and insulated
> >>
> >> Good luck
> >>
> >> Rejean va2am
> >>
> >>
> >>
> >> On Mon, Feb 16, 2026 at 12:52 PM <maflukey at gmail.com
> <mailto:maflukey at gmail.com> > wrote:
> >>
> >> For safety's sake, be aware the soft start and safety interlock
> on some of the AL-1500s were not factory wired per the schematic.
> >>
> >> Matt
> >> KM5VI
> >>
> >> -----Original Message-----
> >> From: Steve Bookout, NR4M <steve at nr4m.com <mailto:steve at nr4m.com> >
> >> Sent: Monday, February 16, 2026 8:48 AM
> >> To: maflukey at gmail.com <mailto:maflukey at gmail.com>
> >> Cc: amps at contesting.com <mailto:amps at contesting.com>
> >> Subject: Re: [Amps] AL-1500 'thump'
> >>
> >> Hello Matt,
> >>
> >> I was wrong about the soft start. It IS in the AL-1500.
> >> My mistake was I asked ‘AI’.
> >> On the schematic, it’s obviously there (K3 and a 10 ohm R).
> >>
> >> Steve NR4M
> >> Sent from my iPhone
> >>
> >>> On Feb 15, 2026, at 8:45 PM, maflukey at gmail.com
> <mailto:maflukey at gmail.com> wrote:
> >>>
> >>> Hi Steve,
> >>>
> >>>>> 'If' it had a soft start to deal with initial current surge, I
> >>>>> might think there was a problem there, but there isn't one.<<
> >>> Did you remove the soft start relay and inrush resistor?
> How old are your PS caps and are they original or upgraded?
> >>>
> >>> Matt,
> >>> KM5VI
> >>>
> >>>
> >>>
> >>> -----Original Message-----
> >>> From: Amps <amps-bounces at contesting.com
> >>> <mailto:amps-bounces at contesting.com> > On Behalf Of Steve Bookout
> >>> Sent: Sunday, February 15, 2026 12:39 PM
> >>> To: amps at contesting.com <mailto:amps at contesting.com>
> >>> Subject: [Amps] AL-1500 'thump'
> >>>
> >>> Hello all,
> >>>
> >>> Had a friend using the station this weekend, and while sitting
> there with him, while operating on 40 meters, we both heard a
> 'thump' or 'thungg' from the amp while transmitting. Happened two
> or three times or a period of a few hours.
> >>>
> >>> Reminded me of the sound the current surge makes when you
> first turn the HV on in an amp.
> >>>
> >>> Puzzling to me cuz if that was it, why and why now? And, no
> other follow up issues. I don't think a PS filter cap would
> 'sorta, kinda'
> >>> short, then not and be OK. It would only be a small part of
> a larger 'event'. (Been there; done that and still remember the
> pucker factor.)
> >>>
> >>> Amp was being operated in a typical fashion, with resonant
> load, 25 watts of drive, ~ 40 ma grid current, +/- 1200 watts RTTY.
> >>>
> >>> Dealt with many amps before, but have not heard anything like
> this in the past. 'If' it had a soft start to deal with initial
> current surge, I might think there was a problem there, but there
> isn't one.
> >>>
> >>> Ideas?
> >>>
> >>> 73 Steve NR4M
> >>>
> >>>
> >>>
> >>> _______________________________________________
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> >>>
> >>
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> >>
> >>
> >>
> >>
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