FL-1 is in the Heathkits and Drake has theirs too.
If the switch doesnt physically move to the unstencilled 10M position then
the detent needs to be defeated so the switch can rotate. Bend out of the
way is the fastest method.
Check the input VSWR on 10M and be sure that the input board has a path from
the coax input to the tubes.
Dont try 12M at full power without removing 5 turns from the plate choke IF
it hasnt already been done.
K5SVC on Ebay usually has the best 572B prices and he supplies the Penta
brand. Ive bought many from him. He is temporarily out of stock (I cleaned
him out).
Carl
KM1H
----- Original Message -----
From: "Roger" <sub1@rogerhalstead.com>
To: "Shack" <noddy1211@sbcglobal.net>; <amps@contesting.com>
Sent: Thursday, November 22, 2007 12:59 AM
Subject: Re: [Amps] Soft 572b's
>
>
>
>
>> When you say Mod, do you mean removing the FL-1 board or whatever it is
>> called? If the board has been removed you also have to a mod to the band
>> switch as well. Sorry to be vague as it has been years since I did this.
>
> IIRC (It was a while back) The only thing I had to do to mine to go on 10
> was the band switch mod.
> No other changes. Same for the DTR-2000 and MLA-2500. I don't remember any
> filter change.
>
> Roger (K8RI)
>>
>> I have the paperwork for this someplace, if it becomes an issue and you
>> don't have it let me know and I will search it out.
>>
>> Mike K6BR
>>
>> -----Original Message-----
>>
>> Hello All
>>
>> I have a Dentron Clipperton L with the original ( and very soft)
>> 572b's in it. I have found that the filament voltage at the tube
>> sockets is 7.49 volts!! I have remedied that problem as well as
>> removing the CB mods and restoring all to original. With the tubes in
>> it the amp will now make about 300-350 watts on all bands and the
>> power supply is in fine shape.
>>
>> My question is that the amp tunes up fine on all frequencies
>> ( including WARC) up to about 26 MHZ but will not amplify 10 meter
>> frequencies at all. The amp does have the 10 meter mod and I have
>> changed the coil tap back to the 10 meter position. Is it possible
>> that the soft tubes might be the culprit? I see tha 572b's are only
>> rated to 30 mhz so 10 meters is right near max frequency/
>> Any help will be greatly appreciated. I just wanted to get this
>> resolved before re-tubing.
>> Tnx es 73
>> Kent
>> N8ZRD
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