[Milsurplus] R1155: Getting to Work

[Andy Young]

Dave,

The Lancaster was a 24volt aircraft. In the aircraft the R1155 and the T1154
were powered by a pair of rotary power units. These were available in 24v
and also 12v versions.

The filament output from the rotary psu is DC, needed by the keying relay in
the Tx, but the Rx is happy on AC or DC at 6.3volts

You'll find the meter fairly easily on ebay (but beware open-circuits), but
the DF loop is harder to find..................

Andy
M0FYA

-----Original Message-----
From: Milsurplus [mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of
David Stinson
Sent: 03 May 2017 06:13
To: milsurplus at mailman.qth.net
Subject: [Milsurplus] R1155: Getting to Work

First: Thank you everyone for your kind help and information on the R1155
resurrection.
I continue to be grateful for our community. Awesome.
This radio is in good, original condition with no hacks. 
The wires- often "rotten" in these radios- are in excellent shape. It is a
better representative of its type than one which has been heavily reworked.
Coil Box cover off:
https://goo.gl/photos/eW8i989mbkpQ1Sqc7

Goals for this repair:
To enjoy the challenge and "puzzle" of reviving the radio in a
minimally-destructive way, thus preserving its history.
To repair it in such a manner that the radio has a good chance to be
preserved by a responsible owner after I am gone.
To acheve these goals, the radio must play. It need not play with 100% of
its original specifications, but it must be capable of basic performance
over extended listening periods. After a long look at it, I think this radio
a strong candidate for the "Lowered B+" solution.
Experience has show that capacitors that leak terribly at 250VDC may
function acceptably at 45 or 90 VDC.
Grid resistors that have wandered from 1 Meg to
3 Megs may still provide acceptable function at a lower overall voltage.
After a first cleaning (deep cleaning later), leached DeOxit into the toggle
switches and pots. Lubricated the mechanical shafts and bearings and
DeOxit-ed the Fuction and Band switch wafers. Gave all the tubes a little
"wiggle" in their sockets. Lit-up the Filament buss and confirmed all tubes
lit. (Was the Lancaster a 6-Volt aircraft?). Let it "cook" with no B+ for an
hour and noted no current spikes or other problems.
An important test with any receiver like this- apply a low voltage to the B+
buss without filament voltage and slowly increase while monitoring the
current draw, looking for shorts or large leakages. Noted currents at 60, 80
and 100 Volts. Little current draw with no filament voltage, so no shorts.
Lit the filaments, put a Heathkit signal tracer on the PHONES connection,
said a little prayer and applied 45 Volts to the B buss.
The radio was on Band 3 (3-7.5 MC) and there was the familiar "BFO-On" noise
floor, but no signals. Found that there is a disconnect between the ANT
connection and the RF Amp. Connected the antenna directly to C59 (grid input
coil for Band 3) and the radio took a breath and played. However, Bands 1
and 2 had no LO operation at 45 Volts, so popped it up to 80 Volts. The
radio came alive then. Had to crank down the signal tracer.
https://goo.gl/photos/h8Fy7EFo56YjHMZ39

B-buss current at 80V was about 15 mills.
After playing it at 80 V. for about 20 minutes, slowly brought the set up to
200 V for a short test, while watching the current. 
At 200V, it pulls about 30 mills. Did not leave it there long. Risky taking
it there in the first place, but I just had to see that eye tube glow.
https://goo.gl/photos/xMS937JEgfpEUFmM8

There's still plenty to do. Need to find that antenna connection issue. Work
over the grounds. 
Test all the tubes. Refurb the Type 35 dial drive.
Determine the "right" B+ buss level for long-term operation and
preservation. Complete alignment.
And a deep cleaning. 
Then to find the loop and meter (wishful thinking).

We're on our way.
GL OM ES 73 DE Dave AB5S

______________________________________________________________
Milsurplus mailing list
Home: http://mailman.qth.net/mailman/listinfo/milsurplus
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Milsurplus at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html