[ARC5] BC-453-B Power Supply
Rich Post
kb8tad at gmail.com
Thu Apr 6 19:20:14 EDT 2023
The capacitors were all 330 uFD at 200 VDC, recycled from modern surplus
(two computer power supplies). Diodes are all cheap 1N4007. Since these
receivers use class A audio output, voltage variations were not a
problem. I tested the DC output with C-7 incandescent light bulbs to
verify load handling. The full write-up for resurrecting and several
approaches to powering a Navy ARA and an ARC-5 are in my articles in the
Jan and Feb 2021 issues of *The Spectrum Monitor, *the monthly PDF
follow-on to Monitoring Times for which I write the monthly radio
restoration column.
Rather than creating a new front control panel for these, if you have an
unhacked unit, the RF gain control, BFO switch, etc., connections are all
accessible at the rear plug in.
I am big on recycling and using modern "surplus". Powering an ARC 5 and an
SCR-274N transmitter for QRP (and QRO) is covered in my columns in the Dec
2015 and Jan 2016 issues. In powering for QRP, I used a pair of
back-to-back UPS transformers (modern surplus) for isolated 120 VAC and
rectified-filtered that for about 160 VDC but also used the 16.5 volts in
between the transformers with a resistor and an LM-317 to feed the
transmitter filaments which had already been hacked a bit and converted to
12 volts. Capacitors and bridge rectifier were recycled from a computer
power supply. For more voltage, a doubling scheme can be used. I did that
for a Navy receiver, but I haven't tried that with ARC-5 transmitters as
yet. For QRO, I used a Heathkit HP-20 with the oscillator and the screen
voltages separately regulated by adding a couple of N-channel MOSFETS and a
heat sink (yes, recycled from computer power supplies) and zeners right
inside the HP-20.
Fun stuff! Enjoy,
73 Rich KB8TAD
On Thu, Apr 6, 2023 at 12:13 PM Dave Merrill <r390a.urr at gmail.com> wrote:
> Rich, what are the values for C1-C4? I was just eyeing a 28VAC filament
> transformer and thinking about using one of those DC-DC boost devices, but
> this is much simpler.
>
> Dave N9ZC
>
> On Wed, Apr 5, 2023, 10:31 PM Rich Post <kb8tad at gmail.com> wrote:
>
>> Since the original question was power supply. Here's a simple method I
>> have used, a 24 volt transformer for the original series filaments. The
>> transformer also feeds a voltage quadrupler with common ground. The 200
>> volt electrolytic capacitors were recycled from a couple of computer power
>> supplies. If you want more than 134 volts, the circuit can be extended to
>> a fifth cap.
>>
>> 73 de Rich KB8TAD
>>
>> [image: Half-wave quadrupler module with common ground.JPG]
>> [image: Voltage quadrupler power supply schematic.jpg]
>>
>>
>> On Wed, Apr 5, 2023 at 10:53 PM <hwhall at compuserve.com> wrote:
>>
>>> Here's a look at another way to do a recap. The terminal board work was
>>> accomplished by Canadian Aviation Electronics (CAE) in 1955.
>>>
>>> Wayne
>>> WB4OGM
>>>
>>> -----Original Message-----
>>> From: Mark K3MSB <mark.k3msb at gmail.com>
>>> To: Robert P. Meadows <rpmeadow at bellsouth.net>
>>> Cc: Dennis Monticelli <dennis.monticelli at gmail.com>;
>>> hwhall at compuserve.com; arc5 at mailman.qth.net
>>> Sent: Wed, Apr 5, 2023 4:52 am
>>> Subject: Re: [ARC5] BC-453-B Power Supply
>>>
>>> " Do the “RECAP” correctly"
>>>
>>> Using Tom Frobase's cap replacement kit is not the "correct" way to
>>> refurbish a receiver; it is an alternate way.
>>>
>>> Tom's kits are very nice as I've looked at them before but on all the
>>> receivers I've recapped I've used just solder lugs or terminal strips.
>>> I've never had any problems.
>>>
>>> As Tom's video says, the only one that's going to know what's inside the
>>> radio is yourself, so what it looks like doesn't matter, and I agree with
>>> him. In the decades I've been restoring radios, never once have I had
>>> someone come into my shack and ask to look under the chassis. If you're a
>>> purist, then you will certainly not want to use solder lugs, terminal
>>> strips, or Tom's kit as none of them are authentic -- you'll restuff the
>>> potted caps. I never restuff the caps; I just save them in a bag with the
>>> radio's serial number on it so when I sell it (or croak...) and my radios
>>> go to the next person they'll have the option to repot.
>>>
>>> Interestingly, Tom seems to make a contradictory statement later in the
>>> video. He indicates that when using terminal strips etc there's no
>>> structural way to put the capacitors in the radio and it looks like
>>> crap.
>>>
>>> If you're going to use your radio in an airplane going through air
>>> combat maneuvering then I'd worry about a good structural way to mount the
>>> replacement capacitors. Otherwise, solder lugs and terminal strips will be
>>> more than adequate.
>>>
>>> I disagree with converting the filaments to 12V - that's just my
>>> opinion; YMMMV. Just buy or build a 28V supply and build a B+ supply. I
>>> used a HB HV supply for years then went over to an HP-23 that I picked up
>>> at hamfest; the LV output on the HP-23 with a dropping resistor works
>>> great.
>>>
>>> Don't get me wrong, I'm not bashing Tom's kits -- they are very nice.
>>> If you have a supply of caps, solder lugs and terminal strips which a lot
>>> of us have, I would not pony up for the price of his cap replacement kit.
>>> If you don't, Tom's kits looka to be a good one stop shopping solution.
>>>
>>> 73 Mark K3MSB
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Tue, Apr 4, 2023 at 10:47 PM Robert P. Meadows <
>>> rpmeadow at bellsouth.net> wrote:
>>>
>>> Do the “RECAP” correctly, purchase Tom Frobase’s capacitor kit, believe
>>> it is kitparts or such. Slick printed circuit boards that hold the
>>> capacitors and fit the existing holes from removing the beeswax filled
>>> leaky tubs. Works well, and I do believe that is what Aircraft Radio would
>>> have done, had such been available.
>>> R
>>>
>>> *From:* arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> *On
>>> Behalf Of *Dennis Monticelli
>>> *Sent:* Tuesday, April 4, 2023 10:38 PM
>>> *To:* hwhall at compuserve.com
>>> *Cc:* arc5 at mailman.qth.net
>>> *Subject:* Re: [ARC5] BC-453-B Power Supply
>>>
>>> If you elect to not restuff the cap pots, it is easy to re-cap the set.
>>> Install a solder lug using the threaded stud that mounts the pot. That's
>>> your ground. Then it's typically three small caps (most are 0.05) from the
>>> lug directly to the stiff wires you cut from the cap pot terminals.
>>>
>>> Yes, lower voltage than 250V works fairly well. My experience is to
>>> keep it at least 60V for decent gain and sure starting of the BFO. The
>>> lower in voltage you go the more you're going to want to short out one of
>>> the R's in the screen voltage divider to keep the gain from decreasing too
>>> much.
>>>
>>> FYI. My 453B pulls only10mA at 60V with new caps. I've run it off a
>>> stack of 9V batteries and they last a long time.
>>>
>>> Dennis AE6C
>>>
>>> On Tue, Apr 4, 2023 at 6:57 PM <hwhall at compuserve.com> wrote:
>>>
>>> Those Command Set receivers had a B+ dynamotor that supplied 250v at 60
>>> mA. Many people operate the sets on lower B+. If these little round
>>> "flower pot" caps are the ones you're looking at, they aren't soldered
>>> shut. The edges are bent over the mica insulators. Most people either
>>> trash the old cap pots or carefully remove, cut them open, restuff & either
>>> glue or solder the cut edge.
>>>
>>> Wayne
>>> WB4OGM
>>> -----Original Message-----
>>> From: Glenn Little WB4UIV <glennmaillist at bellsouth.net>
>>> To: arc5 at mailman.qth.net
>>> Sent: Tue, Apr 4, 2023 7:45 pm
>>> Subject: [ARC5] BC-453-B Power Supply
>>> I have a BC-453-B that has minimal hacks.
>>> At a recent hamfest I found a ARN-30 solid state dynamotor replacement.
>>> This power supply will properly mate with the receiver.
>>> Should this supply power the receiver properly?
>>> Some of the can capacitors along the side of the receiver are leaking.
>>> It looks like these have a soldered on top.
>>> Is it a lot of trouble to rebuild these capacitors?
>>>
>>> Thanks
>>> 73
>>> Glenn
>>> WB4UIV
>>>
>>> --
>>>
>>> -----------------------------------------------------------------------
>>>
>>> Glenn Little ARRL Technical Specialist QCWA LM 28417
>>>
>>> Amateur Callsign: WB4UIV wb4uiv at arrl.net AMSAT LM 2178
>>>
>>> QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
>>>
>>> "It is not the class of license that the Amateur holds but the class
>>>
>>> of the Amateur that holds the license"
>>>
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>>
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