Whats been done to these? - BC453, BC455
 

Hi All,
I recently was given two "Command" receivers from a sk estate, and
would like to get them going (restoration would be a bit tooo ambitious
- too many extra holes, mods, hacks). This is my first "vintage"
project, and would welcome comment on the following (to me) weird
points.

They were bolted together (literally) a BC453 (190Khz to 550Khz) and
a BC455 (6 to 9.1Mhz).The hf one fed the LF one, the BC453 being used
presumably as a "tunable IF - well and good, except that

The 2nd and 3rd IF transformers on the BC455 had been replaced with
ones marked "85Khz" - the first IF/Converter one was 2.83 Mhz, which is
how it was meant to be. Given that the BC453 wouldnt tune EITHER of
these 2 "IF" frequencies, something radical has been done to them!

My question - was this some sort of popular surplus conversion - does
anyone have any idea on how to un-do this butchery - I dont have
"spare" 2.83Mhz if cans, so......am I better of trying to do something
with these, or throwing them back into storage until I find something
thats a more realistic prospect of repair, and keeping these for spare
parts?

I do have the AN/ARC5 manual on my PC, in djvu format - Its
cumbersome, to say the least - not searchable, and at 350 pages, too
big to print out. Any "quick and simple" guides to these things?

Oh, and BTW - the tube mix is all over the place, all 6 volts, one IF
replaced by a 6AC7 - most of the rest unreadable due age etc. And a
6F6 on the BC453 as an audio output tube...

Help!!!!

de VK3BFA Andrew.

Whats been done to these? - BC453, BC455
 

Hi Andrew,

Tried to reply direct to your posting but the sever says your mailbox is
full!

73,
"Andrew VK3BFA" wrote in message
oups.com...
Hi All,
I recently was given two "Command" receivers from a sk estate, and
would like to get them going (restoration would be a bit tooo ambitious
- too many extra holes, mods, hacks). This is my first "vintage"
project, and would welcome comment on the following (to me) weird
points.

They were bolted together (literally) a BC453 (190Khz to 550Khz) and
a BC455 (6 to 9.1Mhz).The hf one fed the LF one, the BC453 being used
presumably as a "tunable IF - well and good, except that

The 2nd and 3rd IF transformers on the BC455 had been replaced with
ones marked "85Khz" - the first IF/Converter one was 2.83 Mhz, which is
how it was meant to be. Given that the BC453 wouldnt tune EITHER of
these 2 "IF" frequencies, something radical has been done to them!

My question - was this some sort of popular surplus conversion - does
anyone have any idea on how to un-do this butchery - I dont have
"spare" 2.83Mhz if cans, so......am I better of trying to do something
with these, or throwing them back into storage until I find something
thats a more realistic prospect of repair, and keeping these for spare
parts?

I do have the AN/ARC5 manual on my PC, in djvu format - Its
cumbersome, to say the least - not searchable, and at 350 pages, too
big to print out. Any "quick and simple" guides to these things?

Oh, and BTW - the tube mix is all over the place, all 6 volts, one IF
replaced by a 6AC7 - most of the rest unreadable due age etc. And a
6F6 on the BC453 as an audio output tube...

Help!!!!

de VK3BFA Andrew.

Whats been done to these? - BC453, BC455
 

sorry, its my old ISP - I never changed my address here in groups (and,
funny - no spam either at the new ISP). try ageinghippy1athotmail.com.
And thanks for your efforts - just assumed replies would be here.....

Andrew VK3BFA

Whats been done to these? - BC453, BC455
 

Good Day, Andrew.
I assume these are actual SCR-274N Army sets
and not AN/ARC-5 or ARA (three different models, all usually
and incorrectly lumped together as "ARC-5").
Unless these are uncommon sets- which would be black wrinkle
and have a tag marked both "SIGNAL CORPS US ARMY" and
"AIRCRAFT RADIO CORP," and have a contract of 1470-NY-41,
then they sound too far gone
for reasonable restoration efforts. Later version
SCR-274N receivers in better shape are common.
Examples with modest modifications that are easily
reversed, such as the "standard" controls in the drawer,
are much less expensive than unmolested sets.
But if you prefer the challenge, you'll need a different
manual. The AN/ARC-5 receivers are not wired the same
as the earlier SCR-274N and the diagrams are not compatible.
What does it say on the nomenclature tags of your sets?
That will help with finding the right diagrams.

73 Dave AB5S

p.s. If they are Aircraft Radio Corp. SCR-274N, they
are worth a big restoration effort.