[sam]

terry
easy fix   get the clapper 
mike shhh don`t say it
so your just moving things around and spreading
you have a very large basement why not use that
sam

[Radioroslyn]

Well a few days ago L76 got a the chance to meet it's little bro 7C . HRO serial # started D in 1935 and run thru mid 1938 with Z. Then they started with the consecutive # made and then the run letter. L 76 is run L (9th) and the 76'th set built and 7C is the 7th set built from run C. It gets a little bit more confusing later when the letters are the same for the pre and post 1938 sets.

Anyway 7C dates to about February 1939. Doubtful that it saw any WWII action as an intell receiver but I have read that some Brits where send over here to purchase HRO's for the govt. This would be probably later in '39 At this time the US was trying to stay neutral so the Lend-Lease program hadn't started that would start a little later. That's when the Brits got most of them and those are a bit newer using octal tubes and having more markings on the front panel. These two use the older standard based tubes.

7C is in good shape and it's not green! Did come with 1 coil 500 to1000kc. All very original and just a few minor repairs. When the previous owner got it it was missing all the tubes and shields. Fortunitly he found them, the proper shields are hard to come by these days the tubes not so much. But he stated that it didn't work.

Now for the dilemma. Should I try to power it up??? There is no hv filters in the set (power supply is separate).

Terry

Below a pic from Bletchley Park (UK) where the Hro's were used to intercept Axis coded messages.

[Radioroslyn]

After a bit of poking around I put power to it. Don't do this at home! Metered the HV current and stayed at 65ma or so. This was ok . All it wanted to do was motorboat and squeal. Joe didn't put the tube shields on it (did retube it as they where all missing when he got it). So put the shields on that got it calmed down to a nice hiss in the spkr. Plugged in the BC band coil set and  and it worked ... well sort of. Xtal filter controls would cause it to quit. Vol control was very noisy and no avc action/S meter movement.

After fussing with it for a while it got better and better. Using the xtal filter controls that settled down. Wiggling the tubes in there sockets helped too. Cleaned the contacts on the coil units. On the HRO all of the adjustment for the RF,Mixer,and Osc are made on the coil units not on the receiver. So the coil units are tuned for a particular chassis/serial #. I have the 4 stock coils for the L-76 (1.7 to 30mc) and that what I'm using in this one (7C).

So it's playing and pretty good at that. Does it need some work you bet.

Terry N3GTE

[sam]

Congrats terry 
Now back to my tv darn it
Sam

[Radioroslyn]

Fixing or watching?? I got the knobs off of the RCA but fell asleep. Gotta get that tuner in!
Terry

[Radioroslyn]

Did get a chance to go into work Monday and drug the L76 chassis with me. While doing some required work I was able to clean it up a bit. Is a little bit rustier than I thought but not real bad. I think for now I going not to deal with the rust but clean it up as best I can and get it working. Will save the rust project for after retirement. So for now I need to repair the leads coming out of the tops IF of the xformers and put the front panel back together.

Terry

[Radioroslyn]

After the chassis cleaning it seemed to be a good time to reinstall the front panel. Got all of the parts together but I'd forgot that all of the screws where still painted with that darn green or grey paint. So into the  citristrip to get them ready for paint. With them all cleaned up mounted into a piece of cardboard they got three coats of wrinkle paint. It takes a good while for it to cure  about two or three days before you can handle  and about a week or two before it completely cures good and hard.

Started to make the index marker for the panel by filling in the tops of some small brass screws with solder and then sanding the solder down to a nice domed head with out the slot. Sounds pretty easy but the solder doesn't take to sanding too well. Was using 220 grit paper and spinning on a drill and it didn't really budge it much at all. Going to use a file to round these heads.

7C has been a lot of fun the play with. After getting her to work. I've listening to her after work and it to night . I get far away places with strange sounding names up on the SW bands and all the familiar sounds of the local BC band. Does a good job with demodulating SSB and CW too. Good and stable.

Terry N3GTE

[Radioroslyn]

Whilst playing with 7C I notice that the audio was a little distorted. So measured some voltages and came to the conclusion that the coupling condenser to the 42 tube was leaky. Located it but noticed that there was a
100K 1W resistor that was disconnected from it's terminal strip. Reconnected it but it made no difference and there was no voltage across it. Hmmm.... Broke out the schematic and found that it supplies the screen grid voltage to the 6B7 (1st audio/det/avc). But why isn't there any voltage  there? Because someone cut out a jumper from a near by terminal strip to that resistor's connection. Checked the resistor and was good. Replaced jumper and condenser. Dang thing plays twice as loud and sound much better. Condenser was OK but got replaced anyway.

Terry N3GTE

[Radioroslyn]

Order came in today from Radiodazes. Some needed caps, rubber feet,and power cord. All of the pre war HRO's use a separate power supply. The earliest ones came with 2.5vac tubes. The reason I mention this is that the 2.5v tubes haul down A Lot of current. Set has nine tubes which equals about 11 amps of heater current. Meaning that the power cord has to be rather robust to handle the current. The OEM National power supply used a power transformer that has a 3vac winding to compensate for the voltage drop though the 4' cord.

The problem is it is difficult to find these days a cloth covered cable four conductor with two 20ga wire and two conductors that are 14  or 12ga to minimize the volt drop. After consulting with Henry over at Radio Boulevard
(Wonderful site for early SW radios) He's used 8 conductor cloth cover battery radio cable by tying 3 of the conductors together for each leg of the heater leads. Great idea.    

L-76 needs the cord replaced and 7C has the original one in fair shape. Both also need 4 pin plugs. So have to scare up a couple of Amphenol  shells and plugs.

Both set have 6V tubes which use about 3amps. Got the front panel back on L76 and power it up. Audio is working but not sure what else yet.

Terry N3GTE                                     

[Radioroslyn]

A few posts ago I mentioned that I got the knobs and fell asleep in persuite of replacing the tuner on my 1950 RCA 6T65 Highlander TV. Well I get the old tuner out and installed the replacement. Got it all back together and back in the cabinet. Some of these older sets the crt is mounted to the cabinet which makes it pretty difficult to try out with the chassis out.
The replacement didn't work. Did some checking and found two bad resistors and two bad connections (ones I made) Fixed that up and It worked just dandy!!! Sound and picture are much better. Before I couldn't get the tuning to adjust to get the sound and pic good together. Either good sound and crappy picture or good sound and crappy picture. But all is well now.
Back to the HRO's Still waiting on Radiodaze for a few back ordered parts.
Terry

[Radioroslyn]

Well Emily is all graduated, just got the B/O stuff from RD so now I can get the radio stuff out of hiding. Except for life has intervened yet gain. Last Friday I was in a car accident totaled my faithful >300,000m '02Toyota Camry. I'm OK but have to deal with insurance co and get a replacement car.
So hopefully I will be getting back to it with in a week or so. Looks like I've got a number of views on the topic and don't want to keep yous guys waiting (or me either)
Oh I did pick up a couple of coils set for 7C (A and C) Would like to find an E coil ( upper half of the BC band and 160m ham band) After I got them I gave the contacts  a good cleaning and was rewarded with good reception.
Terry

[sam]

Well Emily is all graduated, just got the B/O stuff from RD so now I can get the radio stuff out of hiding.

congrats to Emily now you have to pay for collage dad
 
ok I have to say before mike does
but  b/o stuff rd ?
and radio stuff out of hiding   how much stuff are you hiding beside what we seen
better leave room I have stuff for you since mike  and kirk  won`t take it
sam

[Radioroslyn]

She headed off to college in a few months to get a degree in mechanical engineering. She will be doing much better than her OM.
BO isn't a veiled reference to Lifebuoy soap but an abbreviation for back ordered. RD is Radiodazes.
Oh there is lots and lots of stuff in hiding, 40 or so yrs worth. Gota get rid of some of this stuff!

Terry

[Sean]

Hey Terry,

This must be an offspring of your HRO:

http://www.ebay.com/itm/321798170259?_tr...EBIDX%3AIT

They think it is original except the meter.  Too bad they don't have a make offer on it as I might be traveling through that town in the next few weeks (or at least a couple of my co-workers will be).

[Radioroslyn]

I does look a lot like my older one!!! Yes the S meter is a replacement. Original has a square brown Bakelite housing with a orange scale. The innards look pretty good. No sure about the two knobs to the right of the meter. Looks to have a noise limiter which may account for one of the knobs. Also has an output trans mounted under the chassis. If someone wanted to restore the cabinet they are looking at about 8-10hrs to get it all apart do the body work and paint.
The price does seem a bit stiff, I $300 would be a little more fair considering the condition

As for my little HRO projects I haven't been doing much with them. Life keeps getting in the way. The 4th is my granddaughter's birthday (first one!). The 5th I'm headed out to LI NY to go visit Kirk. Ect ect ect...

Tnx for your interest will see if I can drag them out this week. I did get some dud paper caps to rebuild the newer replacement cap that where done in the '60's.

Terry N3GTE