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Today's Topics:
1. Power inverter for sale (RODNEY HOGG)
2. Re: Germanium Transistors (J Mcvey)
3. D Cell in Parallel CAUTION (B. Smith)
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Message: 1
Date: Fri, 24 Oct 2025 15:25:16 -0400 (EDT)
Subject: [MRCA] Power inverter for sale
Message-ID:
Content-Type: text/plain; charset="utf-8"
I found in my cache of stuff something I never knew I had. Have a power inverter, made by Abbott Electronics, Model A1173.
Is solid state with 24-30VDC input with 115VAC output at 400 cycles. rated 1.57Amps. Is brand new OS. Weighs 5.5lbs.
Anyone need/want such a critter? Offer? Neat item.
Rod
K0EQH
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Message: 2
Date: Fri, 24 Oct 2025 20:55:33 +0000 (UTC)
Subject: Re: [MRCA] Germanium Transistors
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I would look for the least leaky ones of the bunch.
Sent from my undisclosed bunker location
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The characteristics are of minimal concern in a low frequency inverter, they operate cutoff and saturated, so linearity is not really an issue. These days, most of these inverters could be served by a single pair of power MOSFETs. I don?t think that is the point.? There is huge satisfaction to be had making this equipment work as designed, within the bounds of reason.? As far as ?rot? goes, there was a problem with early Germanium semiconductors with ?purple Plague?? wherein gold bond wires on aluminum metallization formed an intermetallic compound (rather than a true alloy) which eventually destroyed the device by virtue of its poor conductivity and very low melting point.? Aluminum wire bonds eliminated the problem.? However, I have dozens of devices that are up to 70 years old that are still percolating along (ARC-58, URC-32, AIC-10 intercoms, PRC-21s, etc.? Some devices do and will fail, but don?t write all of them off unless there is evidence of a real problem.? Hope thi
s sheds some illumination of the topic.
?
Scott W7SVJ
?
Sent: Wednesday, October 22, 2025 11:38 AM
Subject: [MRCA] Germanium Transistors
?
Do NOS germanium transistors get ?rot? or go bad from age?? I need to replace the invertors in a PRC-47 and I have 5 NOS original germanium transistors.? All test vastly different. I expect variations as not matched sets but these are WAY off.? I suspect at least 60 years old and maybe much more.
?
Ron Boltz
K3tzj
?
?
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Message: 3
Date: Sat, 25 Oct 2025 11:42:03 -0400
Subject: [MRCA] D Cell in Parallel CAUTION
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??????? Several members are evidently using two (2) D cells in parallel
to power the filament chain of receivers such as the GRC-9, BC-611, and
GRC-109. I've mentioned a "Melt Down" problem with this procedure
numerous times on my BC-611 and BA-48 page.
??????? Over the years I and several other membershave experience
multiple instances of D cell battery packs consisting to two Alkaline
Manganese Dioxide cells wired in parallelcreating very high
temperatures. We call this phenomenon "Melt Down."In BC-611's the case
gets so hot you could not pick up the radio if you touched the area
where the battery pack was inserted. Fortunatelyeach time the "Melt
Down" occurred the radio was either in the field or on the bench and not
being stored or on the shelf.
???????? In each case the manufacture was Duracell or Energizer. It is
mentioned briefing in their safety sheets that the "Batteries may
explode or leak, and cause burn injury, if recharged. . ." I hate to
mention brand names but these manufactures make an excellent battery and
thus their cells have enough energy to cause "Melt Down" which occurs
when one battery is trying to charge the other battery.
??????? In most cases two D cells are overkill in powering the filament
chain of our military reeivers when one battery wouldsuffice. I
recommend that if you insist on using two cells in parallel that you
insert the batteries only for the exact time that you need the receiver
to be powered and that you monitor for over heating. Remove the
batteries when not in use.Do not store the battery pack on the shelfin a
parallel configuration. It has been reported that batteries that were
exposed to high temperatures in the sunlight prior to use were prone to
"Melt Down."
Safety sheets for these batteries should bedownloaded and read.
K4CHE
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End of MRCA Digest, Vol 258, Issue 34
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