It might be worth powering up the amp with the tubes out just in case
you have a problem with a tube.
I had one tube that was very low emission but was able to re-activate it
using the circuit described here:
http://www.xs4all.nl/~pa0fri/Lineairs/TL922/tl-922eng.htm
<http://www.xs4all.nl/%7Epa0fri/Lineairs/TL922/tl-922eng.htm>
there's also a lot of good engineering tips on PAR0FRI's pages.
So far I've put the HT glitch resistor and fuse in and changed the
suppressors.
My amp is happiest on 40m (no surprise there really) and will provide
approx 1150W out, dropping to about 950W on 10m.
Mike G8TIC
On 21/01/2011 14:28, BEHIELS JEAN-PIERRE wrote:
> Thanks for the good technical explanation.
> I really don't need this accurate measure around this 47ohm/50W resistor,but
> I have done due the fact I saw he has coming up very hot !
> Maby I measured in DC position or not,I could not confirm(maby I measure
> wrong,but there flows more than a few hunderd mA !!! )
> I can suppose my environmental measurement was quit a signal for my that
> there must flow a lot of current without any charge.
> Due the hot temperature around the 47ohm resistor and the big current I saw,I
> was curieus if this is normal value with no charge for the high tension
> supply of this TL922 unit ?
> The capicitors and there bleeders resistances are very difficult to reach
> inside the cabinet for a DC voltage measurement !!
> To be honest I never saw sutch high no-charge currents for a amplifier
> unit,what wouldit be with charge more than presumed I think (Ic for a TL922 =
> max 650mA)?
> I will do a effort next days to reach the capacitors and there bleeders to do
> a DC measuring again.
> I must say nothing has been blowed-up after about 8 hours of no charge
> service,thats the reason I am not really scared around,but I must say it is
> mutch has a idle currrent value I found ??
>
> 73's
> Jean ON4AEF.
>
> ----- Original Message -----
> From: TexasRF@aol.com
> To: ON4AEF@base.be ; amps@contesting.com
> Sent: Friday, January 21, 2011 2:30 PM
> Subject: Re: [Amps] Fireing up a old Tl922 amplifier.
>
>
> Hi Jean, there several ways to measure the 1A current flow. One method is
> to measure voltage drop across the 47 ohm resistor. If you are doing that
> with a typical digital voltmeter it will display a value that is
> approximately .707 times the peak voltage. Since the filter capacitors are
> charging only on ac peaks, you are not delivering power to a totally
> resistive load. As a result, the waveform across the resistor will not be a
> sine wave and the voltage reading will be much higher than the rms value.
>
> An accurate current reading will require use of an average reading ampere
> meter such as iron vane type. For your purposes an accurate reading is not
> needed.
>
> If you are measuring voltage drop across the 47 ohm meter and seeing 47
> vac, then your reading is very similar to some I have taken with a 35 ohm
> resistor in the primary of a hv power supply. In my case, I was using the
> resistor to reduce the standby dc voltage to equal the full load voltage.
>
> If you can measure the dc voltage across each filter capacitor it will
> give a good indication how they are forming. If one is much lower than others
> it indicates leakage and perhaps needs more time to form or is defective. It
> could also indicate the bleeder resistor has changed value and needs
> replacement. If a capacitor reads much higher than others it indicates the
> bleeder resistor is defective and needs replacement.
>
> 73,
> Gerald K5GW
>
>
>
>
> In a message dated 1/21/2011 1:58:05 A.M. Central Standard Time,
> ON4AEF@base.be writes:
>
> Hi;
>
> Best wishes for you all for 2011.
>
> I am quit making my own start delay into a old (1988)TL922 amp.
> I made two primary transformer start up delays for : A for filament
> supply.
> B for HV sequencial
> start-up supply.
>
> A little explanation about my substantial modifications concerning the
> TL922 power supplys.
> By powering-on I switch all ready a resistance of 10 ohm/50W into the
> primary of the filament transformer circuit.
> After about 3 minutes I switch on the HV tension with in series a
> resistance
> of 47ohm/50W by means of timer T1
> I mean time I also swich-out the 10 ohm/50 W of the primary of the
> filament
> transformer by means of that same timer T1'
> After 5 minutes I switch-out the 47 ohm/50W resistor of the primary of
> the
> HV-supply transformer by means of timer T2.
>
> This principle works quit very well and it is very safely for the
> start-up
> life time of the 3-500Z tubes ?
> But I was a little bit scary about the cuurent (1A over 47 ohms is 47W
> !!!)witch flows of the HV-supply
> without charge during the 47 ohm/50W resistance was in circuit..
> Just some bleeders resistances over the HV-supply C's and over the whole
> supply as stabilisation of the power HV-supply output.
> I could not believe it was about 1A ???
> That was quit a good reason to ask some question around ?
> Today I leave the whole AMP under supply for a whole day nothing happens
> around.
> May I conclude everything is normal behind my old Tl922 ?
>
> So a big story but I like to now some others guys opinion and experiences
> around this remarquable
> consumption of the HV-supply and measurement I made around a TL 922.
>
> 73's Jean ON4AEF.
>
>
>
>
>
> > ----- Original Message -----
> From: "Jim W7RY"<w7ry@inbox.com>
> > To: "BEHIELS JEAN-PIERRE"<ON4AEF@base.be>;<amps@contesting.com>
> >> Sent: Wednesday, January 19, 2011 4:20 PM
> >> Subject: Re: [Amps] Fireing up a old Tl922 amplifier.
> >>
> >>
> >>> How long is your delay? Should be no more than .5 second to 1
> second.
> >>>
> >>> 73
> >>> Jim W7RY
> >>>
> >>>
> >>> --------------------------------------------------
> >>> From: "BEHIELS JEAN-PIERRE"<ON4AEF@base.be>
> >>> Sent: Wednesday, January 19, 2011 12:18 AM
> >>> To:<amps@contesting.com>
> >>> Subject: [Amps] Fireing up a old Tl922 amplifier.
> >>>
> >>>> Hi,
> >>>>
> >>>> I am busy to fireing up a old Kenwood TL922 amplifier(1985).
> >>>> I have already build in a start-up system for both filament and
> high
> >>>> tension power supplys by means of two homebrew timers,and a series
> >>>> small
> >>>> resistances in
> >>>> de secundairys of both transformers(filament 10 ohm-HV 47 ohm both
> >>>> 50W).
> >>>> Both valves are not mounted(running with no charges no consume).
> >>>> By power-on the unit I saw that the resistance of 47ohm/50W into
> the HV
> >>>> supply is becoming very hot.
> >>>> I have made some measurements during start up around this
> resistance
> >>>> and
> >>>> measure 47 V over this resistance.
> >>>> This means that the HV power supply without charge consume 1A
> idling
> >>>> current !!!
> >>>> Question is this normal ?
> >>>> After the timing sequence the resistance is normally pulling out
> of the
> >>>> system and the supply runs like it must be I suppose,nothing
> abnormal
> >>>> happens further !!
> >>>> No overheating behind the amplifier box or whatever,no smoke or
> burning
> >>>> and heating components.
> >>>> Just the 10W bleeders over the capacitors warm up a little (can
> easely
> >>>> take my hand on it hi )
> >>>> I was wondering while this is so mutch or not ?
> >>>> Did I leave the amp a lot many hours under supplying condition to
> the
> >>>> give the HV-capacitors the time to reforme after sutch long time(if
> >>>> this
> >>>> is the reason) ???
> >>>> Could this last also a reason of the fenomene ?
> >>>> Or is 1A just normal standby current value for this amp .....
> >>>>
> >>>> Regards Jean ON4AEF.
> >>>>
> >>>> _______________________________________________
> >>>> Amps mailing list
> >>>> Amps@contesting.com
> >>>> http://lists.contesting.com/mailman/listinfo/amps
> >>>>
> >>>>
> >>>>
> >>>> -----
> >>>> No virus found in this message.
> >>>> Checked by AVG - www.avg.com
> >>>> Version: 10.0.1191 / Virus Database: 1435/3389 - Release Date:
> 01/18/11
> >>>>
> >>
> >
>
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