[Central-Electronics] Central-Electronics Digest, Vol 70, Issue 8
NICKTUSA at aol.com
NICKTUSA at aol.com
Sat Mar 27 14:49:28 EDT 2010
Well, first off I don't have quite 50 years experience with CE rigs, as
then I would have started when I was a mere lad of six! I have known Wes
Schum since my college days. We became friends and soon after my
mentor....and who could have a better mentor than he?
The 200V was designed with solid state rectifiers so the transformer was a
minor redesign ...fewer secondary turns on the B+ winding and elimination
of the two rectifier filament windings. The rigs were tested at 117vac and
the voltage allowed to vary between +/- 10%. Wes, always the realist, did
not build anything to design centers and hope it would work under field
conditions. When I was helping him with the Schum Electronics high voltage
breakdown equipment line, each product had to pass the +/- 10% upper and
lower line voltage limits and no component "abused" along the way. That said,
it obviously doesn't hurt to adjust one's line voltage to meet equipment
design centers. If your line voltage is well above 120vac, call the utility
company and make them do a tap change on your outdoor pole/pedestal
transformer (sometimes this requires installation of a different transformer). I
had my utility do this for me and it was no big deal. Just ask nicely!
Back to the CE 100V and elevated temperatures. The 100/200V power
transformers were designed for continuous service, not intermittent use as many
amateur equipment manufacturers did after ssb took hold. Of the fifty six
transformers left after CE stopped 100/200V production, only four of that
replacement stock have been used as replacements...they rest lived a life of
leisure in Wes' garage...now they are doing the same here in Covington.
Lightning seems to be their killer, not heat. Even the filter caps having
been baked by tube rectifiers for fifty+ years have stood the test of time.
They have become a problem just within the past seven or so years. Just
replace them with the specials I had manufactured and these sets will live
another 40+ years if cared for.
Actually, the slow warm up characteristic of the rectifier tubes is much
better for the capacitors as this essentially current-limits the charging
surge. When I was full bore into the CE restoration biz prior to August
2005, most of the capacitor changes I did were on 200Vs as the instant-on
brought a potential sudden and instant death for those old caps. That's why I
had the new caps made.
By the way, my old CE technician...Merlin...is returning on Monday and we
will be able to restart restoration services again.
Please visit the Tusa Consulting web site (_www.tusaconsulting.com_
(http://www.tusaconsulting.com) ) as Bob Sullivan, W0YVA, has been adding
newly-found Central Electronics info on the site. I have acquired a huge stack of
CE documents from Wes and these are just incredibly interesting. I will be
posting the significant ones on my web site as they give a wonderful
glimpse into the inner workings of a historically important radio manufacturing
company of the time. To those interested in the design of high performance
AF phasing networks, and the phasing method of ssb generation/detection
itself, you will find some interesting info and a few surprises on the site
very soon...perhaps by this weekend if Bob hasn't found too many great deals
at the hamfest he planned to attend today..
Please let Bob know about interest in the replacement meters and KC dials
as he is collecting a list to see if there is sufficient interest to make
their production economically viable. The originals are looking pretty
scruffy from the effects of heat and the unstable plastics of the 1930-40s that
were still widely used, post war. I've found a quality source for these
parts, but between Bob and me we might need only six or so for our own
collections....not quite enough of a known interest to consider sticking our
necks out for several hundred pieces of each type part!
73 Nick K5EF
In a message dated 3/27/2010 11:01:20 A.M. Central Daylight Time,
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Today's Topics:
1. 100V vs 200V voltages (k6jek)
2. Re: 100V vs 200V voltages (KEN)
3. Re: 100V vs 200V voltages (Ted Saba)
----------------------------------------------------------------------
Message: 1
Date: Fri, 26 Mar 2010 11:17:59 -0700
From: k6jek <k6jek at comcast.net>
Subject: [Central-Electronics] 100V vs 200V voltages
To: central-electronics at mailman.qth.net
Message-ID: <FC688A01-C2F3-4F7A-BB98-3433BCA40F45 at comcast.net>
Content-Type: text/plain; charset=us-ascii
Anyone out there with experience with both the 100V and 200V?
My 100V has solid state plug-ins for both high voltage supplies. These
make the voltages a good notch higher than the voltages in the book even with
the AC mains voltage down at 115 V.
I'd like to stay with the plug-ins because the transmitter is hot enough
with out two more rectifier filaments burning. I'm considering doing
something to take the voltage down a bit at least for the low B+. But is it
actually a problem?
I believe the 200V went to solid state rectifiers didn't it? Did CE
change the power transformer or live with higher voltages?
Any information would be much appreciated.
Thanks,
Jon
------------------------------
Message: 2
Date: Sat, 27 Mar 2010 04:55:05 -0500
From: "KEN" <n5cm at rtconline.com>
Subject: Re: [Central-Electronics] 100V vs 200V voltages
To: "k6jek" <k6jek at comcast.net>, <central-electronics at mailman.qth.net>
Message-ID: <2D4DECFA16994440B560FF87D335FFB4 at yourb27fb1c401>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Hi Jon,
Contact Nick Tusa, the expert on Central Electronics equipments and had
been
over a half century to my knowledge.
He restored my 100V and I bought a 200V from him that he had restored.
I don't have his Email address handy but I'm posting this also on the list
so maybe someone can supply you with his Email address.
Good luck!
Ken N5CM
----- Original Message -----
From: "k6jek" <k6jek at comcast.net>
To: <central-electronics at mailman.qth.net>
Sent: Friday, March 26, 2010 1:17 PM
Subject: [Central-Electronics] 100V vs 200V voltages
> Anyone out there with experience with both the 100V and 200V?
>
> My 100V has solid state plug-ins for both high voltage supplies. These
> make the voltages a good notch higher than the voltages in the book even
> with the AC mains voltage down at 115 V.
>
> I'd like to stay with the plug-ins because the transmitter is hot enough
> with out two more rectifier filaments burning. I'm considering doing
> something to take the voltage down a bit at least for the low B+. But is
> it actually a problem?
>
> I believe the 200V went to solid state rectifiers didn't it? Did CE
> change the power transformer or live with higher voltages?
>
> Any information would be much appreciated.
>
> Thanks,
>
> Jon
> ______________________________________________________________
> Central-Electronics mailing list
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>
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------------------------------
Message: 3
Date: Sat, 27 Mar 2010 07:50:59 -0500
From: "Ted Saba" <tgsaba at bellsouth.net>
Subject: Re: [Central-Electronics] 100V vs 200V voltages
To: "KEN" <n5cm at rtconline.com>, "k6jek" <k6jek at comcast.net>,
<central-electronics at mailman.qth.net>
Message-ID: <51B4FAD43B4F49239B9B2BD4943C9B0B at TEDKN5O>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
You can email Nick @ nicktusa at aol.com
73,
Ted
KN5O
----- Original Message -----
From: "KEN" <n5cm at rtconline.com>
To: "k6jek" <k6jek at comcast.net>; <central-electronics at mailman.qth.net>
Sent: Saturday, March 27, 2010 4:55 AM
Subject: Re: [Central-Electronics] 100V vs 200V voltages
> Hi Jon,
>
> Contact Nick Tusa, the expert on Central Electronics equipments and had
> been
> over a half century to my knowledge.
> He restored my 100V and I bought a 200V from him that he had restored.
> I don't have his Email address handy but I'm posting this also on the
list
> so maybe someone can supply you with his Email address.
> Good luck!
>
> Ken N5CM
>
> ----- Original Message -----
> From: "k6jek" <k6jek at comcast.net>
> To: <central-electronics at mailman.qth.net>
> Sent: Friday, March 26, 2010 1:17 PM
> Subject: [Central-Electronics] 100V vs 200V voltages
>
>
>> Anyone out there with experience with both the 100V and 200V?
>>
>> My 100V has solid state plug-ins for both high voltage supplies. These
>> make the voltages a good notch higher than the voltages in the book even
>> with the AC mains voltage down at 115 V.
>>
>> I'd like to stay with the plug-ins because the transmitter is hot enough
>> with out two more rectifier filaments burning. I'm considering doing
>> something to take the voltage down a bit at least for the low B+. But is
>> it actually a problem?
>>
>> I believe the 200V went to solid state rectifiers didn't it? Did CE
>> change the power transformer or live with higher voltages?
>>
>> Any information would be much appreciated.
>>
>> Thanks,
>>
>> Jon
>> ______________________________________________________________
>> Central-Electronics mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/central-electronics
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Central-Electronics at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Central-Electronics mailing list
> Home: http://mailman.qth.net/mailman/listinfo/central-electronics
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Central-Electronics at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
------------------------------
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