BC-610 E... Finally!

[N6YW]

It's been almost a year and it finally made it on the air today.
What a thrill, and a troubleshooting session (they all do this) to boot.
The storage room location for the Gates BC-1H needed to be cleared, so that meant the BC-610 E had to become a part of the shack. Not being ready for the tear down and re-configuration of the shack and it's furniture and equipment, I said screw it. Move some stuff out and make room for much needed stuff.
I paired it up with a National HRO-60 and it worked just fine but when the SX-28 restoration is complete, it will take the HRO-60's place. Of course.
Here are some birthing pics. Some work still to be done. The can electrolytics are shot, so I have to replace them soon. But, the sheer beauty of this rig is undeniable. I am one lucky SOB.
73 de Billy N6YW

[N6YW]

More pics...

[W6DRZ]

And it sounded good last night, also.
Congrats. Billy!

[N6YW]

Thank you Craig.
Rick K6FMB reported the presence of 120hz ripple on my carrier, and somewhat dominant. I need to isolate what is causing this.

[ka4koe]

This is a gorgeous piece of work. Congratulations!

Philip

[N6YW]

Thanks Philip!
Just a few things to work out. It's never really been fully serviced and that alone is a testament as to how well these things were engineered and built. I look forward to finishing it off and finally pairing it with the
SX-28 that is being restored. It will be quite a fine evening when they are both running as a package!

[WBear2GCR]

Looks great!
Love the styling on them.

This was run through photoshop and looks better on my screen.

[N6YW]

NICE!!!!
I really do need a new rug!

[KC4VWU]

It's way cool , and IMHO, the best looking in the series! It really dwarfs the GK. Do you know the dimensions, right off hand?

73, Phil

[w1vtp]

This one's my fav...  I like the angle

Congrats

Al

[K1NSS]

Just too, too much.  Straight out of my kid ham dreams, looking at ancient QST ads, wishing I grew up Art Collins before I knew who Art Collins was.

[N6YW]

Thank you gentlemen...
I figured out what was causing the ripple... the tuning unit. I will fix that by wiring up
an external VFO and be done with it. I don't have a crystal for 3870 or 3885, otherwise I would
be happy with being rock bound. I have a Johnson VFO 122 that I can fix up with it's own power supply and I think it would have sufficient drive for this beast.
Thoughts?

When I first got into AM 3 years ago, I was fortunate enough to inherit the entire bound QST magazines from 1948 thru 1970. It reinforced my desire to chase my childhood dreams of having real radios, the kind that made an immediate impression when someone walks into the room. I saw the BC-610 in it's various forms in those old magazines, thus I went nuts on the internet looking at web pages of various people who own and operate these wonderful boxes. I was hooked. It became my mission to own one and wouldn't you know that a chance to do this was through an event where a bunch of us went to aid a friend who had just purchased a 20V-2 and had to move it. Lucky me... he brought his (mine) BC-610-E to be sold because he couldn't have both. I made the deal right there and picked it up next month. Since then, it sat in the storage room next door to my shop waiting to go back online.
It's now making power and QSO's and tonight is FUN FUN FUN!!!

[Opcom]

I've seen that plate cap before! How does it hold up on that hot tube? Those seem to be some kind of hard plastic and wear well on hot tubes and against corona. made for horizontal outputs.
The carpet is fine. All it needs is a cat or dog curled up on it. I like comfortable looking well worn carpets. They have character.

K1NSS - good to see your post, long time no see!

[W2PFY]

the tuning unit

I drive mine right at the crystal socket. I use a 50 ohm non inductive resistor right across the coax mounted on the banana plug that fits right in to the socket. Works great!

[N6YW]

I've seen that plate cap before! How does it hold up on that hot tube? Those seem to be some kind of hard plastic and wear well on hot tubes and against corona. made for horizontal outputs.
The carpet is fine. All it needs is a cat or dog curled up on it. I like comfortable looking well worn carpets. They have character.

K1NSS - good to see your post, long time no see!

The new guitar amplifier that I am building now is actually the brain child of Joe Walsh WB6ACU. The amplifier model called the G Craft MK1 is an all tube amp that uses 3 bands of opto compression and a set of 3 807's wired in parallel single ended class A. He showed his true colors as an old school ham by insisting on using 807's. So, I have a bunch of these plate caps complete with 20KV rated line. I now use 6550's instead of the 807's for some very defined reasons. The amp has gone under some design revisions as well, so I have some spares. The plate caps are very heavy duty and appear to be Micalex or some form of space age plastic. I had to replace the old dilapidated HV wire and connector. It was time.

[K6JEK]

Great job, Billy. Remember the 610 is a mobile transmitter so I'll expect to hear you running it from somewhere out in the wild. You might want to bring that Harris tuner along to match your portable antenna.

[N6YW]

Great job, Billy. Remember the 610 is a mobile transmitter so I'll expect to hear you running it from somewhere out in the wild. You might want to bring that Harris tuner along to match your portable antenna.

But of course Jon. I have very high standards you know. I always operate QRO AM when mobile.

[N6YW]

BTW...
While tracking down the source of the low frequency artifact on my carrier, I did a simple test.
I removed the 6V6 tube from the oscillator circuit. Duh... no noise and no carrier but it confirmed that there in lies the problem. While monitoring with my Flex 5K I noticed that adjusting the Int. Amp and Doubler controls allowed a null to occur when the circuit came to resonance at the point where I had maximum carrier output. My conclusion is the dirtiness of the tuning unit and this will be solved with running a remote VFO or a crystal.
So, have any of you ever noticed this when using the tuning units, and does this happen with all of them band to band? Is there a modification that removes this artifact from appearing on the carrier when using the tuning units? Just curious. I imagine there was a bit of acceptable hum seeing how it was war time and the aspect of fidelity was not a primary concern.

Another item needs to be addressed. I performed the "talking relay" mod using a 100uf 450 electrolytic across the coil of the relay. It made very little difference. I seem to recall that someone posted a mod that involved the center tap of the modulation transformer. Perhaps I can benefit from doing the correct method of getting rid of this annoyance, because it occurs right about the 100% modulation level.
Ha, maybe I could use it as a modulation "monitor".
Thanks. What a fun night and the damn thing works. 70 years old and still percolating.
73 de Billy N6YW

[W2VW]

Here's some interesting reading which contains the answer to the hummm q.

http://amfone.net/Amforum/index.php?topic=4135.0;wap2

[Steve - K4HX]

This one is much easier to read.

http://amfone.net/Amforum/index.php?topic=4135.0


The hum problem is a well-known one since the days when the BC-610 showed up on the ham bands.

[N6YW]

I spent the entire day building an add on power supply pack for my Johnson VFO 122 to use with the BC-610. I have been under the assumption that it should produce at least 8-10 volts RMS. Well, I'm not even getting 20mv out of it although I can hear it and see it on my flex 5k. It will not drive the oscillator in the 610, so something is wrong. Don was kind enough to give me the rundown on how to implement an external VFO with the rig. I did that. When I finished the VFO power supply, all of the voltages seem okay and it does key up a signal but it's weak. I changed the osc. tube with no change.
Here are some pictures of the VFO supply. It's a piggyback affair that utilizes the octal socket that someone had installed sometime in the past. Pretty slick arrangement.

[N6YW]

Here's the last shot of the supply.

[Opcom]

I've seen that plate cap before! How does it hold up on that hot tube? Those seem to be some kind of hard plastic and wear well on hot tubes and against corona. made for horizontal outputs.
The carpet is fine. All it needs is a cat or dog curled up on it. I like comfortable looking well worn carpets. They have character.

K1NSS - good to see your post, long time no see!

The new guitar amplifier that I am building now is actually the brain child of Joe Walsh WB6ACU. The amplifier model called the G Craft MK1 is an all tube amp that uses 3 bands of opto compression and a set of 3 807's wired in parallel single ended class A. He showed his true colors as an old school ham by insisting on using 807's. So, I have a bunch of these plate caps complete with 20KV rated line. I now use 6550's instead of the 807's for some very defined reasons. The amp has gone under some design revisions as well, so I have some spares. The plate caps are very heavy duty and appear to be Micalex or some form of space age plastic. I had to replace the old dilapidated HV wire and connector. It was time.

Opto with incandensant, biased (class A-style) LED, or straight IC-type optocouplers?
Very interesting!
Anyway the plate cap reminded me of good ole days when bin-boxes overfloweth. Specters of surplus stores long gone.
SE Class A is its own reason for 6550's over 807's.

[N6YW]

Yup...
Those are the ones. Very nice caps and the fit is snug.
These opto isolators are the LED type, Vactrol brand. Jon Peterson of Tube Tech fame designed the compressor circuit and is pretty much the same design as used in the Tube Tech SMC-2A stereo compressor.
I am considering building one without the SE output stage as used for signal processing instead.
Include a transformer balanced input and output, Phantom power and adjustable input gain.

Anyway, back on topic. Presenting the BC-610-E on the AMI West Coast gathering tonight for the first time. I know I'll get the complaint about the ripple and hum on the carrier but for now I'm not concerned.
I'm just tickled to death having the Mother Ship on the air, and until I get the VFO problem straightened out the tuning unit will have to do. Unless someone has a 3870 khz crystal they want to part with?
Presently, I have not determined why I'm not getting any AC voltage on the output of the VFO.
Strange.

[KD6VXI]

Do you not own a ricebox?   They make great VFO devices :-)

--Shane
KD6VXI