B&k 1077 - Videokarma.org TV - Video

TUD1 · #1 07-30-2016, 02:07 PM

Got this at the radio club today for the Best Price. It's in okay shape, but the sides are all rusted, and the yoke is falling apart. I plugged it into the variac and brought it up real slow, but the magic smoke still managed to escape. It was pulling over an amp at 60 volts. I'll replace the lytics maybe next week. I only have one slide. It has all the original Dynascan tubes except the photo multiplier tube, which is an RCA. The CRT tests very strong. At first, it tested dead, but after 10 minutes, it started waking up.

davet753 · #2 07-30-2016, 02:50 PM

Good Lord, I haven't seen one of those in years. I had one, and a set of the transparent slides to make the test patterns with. An odd piece of test equipment, that's for sure. As I remember, it wasn't used much.

Electronic M · #3 07-30-2016, 08:57 PM

They are super useful for diagnosing, Sweep, and "no signal" problems. Mine gets used every few sets.

Phil Nelson · #4 07-30-2016, 11:10 PM

A 1077 is very handy in some situations. This 1077B article has a schematic and voltage chart, plus scans of the standard slides:

http://antiqueradio.org/BK1077BTelevisionAnalyst.htm

Hope you get yours working correctly!

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

DaveWM · #5 08-01-2016, 12:14 PM

I have a 1076, also find it handy for signal injection. I found a "recapped but does not work now" problem with it by injecting the composite video. Also as mentioned handy for checking yokes/flys (has a test for that) and generating sweep signals to power up horz and vert sweep circuits.

Beware of shot gunned recappers, esp with point to point circuits (easier to mess up than PCB stuff where you cant really wire it up wrong only use wrong values or polariites).

Electronic M · #6 08-01-2016, 01:03 PM

Quote:

Originally Posted by DaveWM

I have a 1076, also find it handy for signal injection. I found a "recapped but does not work now" problem with it by injecting the composite video. Also as mentioned handy for checking yokes/flys (has a test for that) and generating sweep signals to power up horz and vert sweep circuits.

Beware of shot gunned recappers, esp with point to point circuits (easier to mess up than PCB stuff where you cant really wire it up wrong only use wrong values or polariites).

Some PCBs do have spare lead holes in bad places...I've caught myself almost doing that once or twice...

DaveWM · #7 08-01-2016, 05:10 PM

I have seen that where caps have axial or radial holes. Still a lot harder than term strips. That one really had me going. Part of the problem was he said it worked (well yea if you put about 1v RF in at the tuner, you could barely get something that looked like a pic on the CRT). 1076/77 are fun to play with, make shadow puppets!

old_tv_nut · #8 08-01-2016, 06:46 PM

When I worked on the CBS/Motorola EVR video player, we noticed that the Hamamatsu PMTs were less noisy than the RCAs, but would become equally noisy if exposed to fluorescent lighting.

I do not know or recall if the output decreased and the extra noise came due to turning up the dynode voltages.

I do not know if they recovered after some time, as we did not re-use the degraded ones and carefully replaced them with new PMTs in a relatively dark room. The players were demo units, so we wanted to cherry pick the least-noisy units.

I speculated that the Hamamatsu PMTS were assembled and packaged in a dim environment and the RCAs came "pre-exposed," but I have no actual knowledge of that. Photoemissive materials are so open to degradation that it could easily have been a difference in processing, not light exposure at the factory.

kf4rca · #9 08-02-2016, 07:43 AM

The 931 is used in the original 1076. The new 1076B uses a different tube, has more pins. Not interchangeable. I have one of each. I suspect the 1077 uses the newer tube.
The newer tube produces a sharper image.
Be careful when removing the tubes as the keyway sometimes breaks off allowing incorrect insertion.

kf4rca · #10 08-02-2016, 02:00 PM

one has a 4422 and the other has the 931. Both are 11 pin tubes and from what I've read, they should be interchangeable.
The 1076B is distinguishable by the 3 pos'n audio switch and the RCA jack on the back for external audio.
Believe some of these units were marketed for the hotel/motel industry so they could display messages over their MATV system.

N2IXK · #11 08-02-2016, 02:26 PM

The 4422 is one of RCA's "mystery" types in the 4000 series. Many of these had little or no published data available, being modified or selected versions of standard types, usually for sale to a single customer.

I have access to a fair number of internal RCA tube division documents (including a bunch of the 4000 series types) and a shelf full of tube databooks, but nothing on the 4422. B&K themselves suggested the use of the 931A as a replacement type, rather than offering the 4422 as a replacement part. This would lead me to believe that it may have been an "off-spec" 931A that was "good enough" for the intended application (which isn't all that demanding compared to most PMT applications in scientific instruments and such) , and was sold to B&K at a discount. Not all "selected" tubes were "better" than their prototypes, and this MAY be one of those cases.

Only a former engineer from RCA or B&K would be able to give the definitive answer on this one, I'm afraid...

kf4rca · #12 08-03-2016, 07:30 AM

I looked at my RCA Photomultiplier Handbook (ca. 1980) and there is no listing for the 4422. There are other 4000 number tubes all classified for imaging purposes.
There are two 931 tubes listed- an A and a B version. The difference is the formula for the photo-conductive surface.

kf4rca · #13 08-05-2016, 08:05 AM

Some of those B&K's had selenium rectifiers. That could very well be the source of your smoke. If you have vertical linearity problems, change the two 2.2Meg resistors in there.
You can make extra slides yourself. Download the desired image and print it to paper on an ink jet printer. Take that image to Staples or Office Depot and ask them to make a transparency. Tell them extra contrast when they print it on the laser jet. Cut the transparency to the desired size. The transparency will cost about 75 cents.
If the image is too big, you will have to use a graphics program to scale it down. I use GIMP which comes in Ubuntu Linux but I am sure Microsoft has similar programs. I found the desired size is about 300x400.

Electronic M · #14 08-05-2016, 11:16 AM

Gimp was ported to windows ages ago, but the installer is kinda spamy.

kf4rca · #15 08-05-2016, 04:07 PM

They also make it for Mac OS X.
And then there is:
www.resizeimage.net.
There used to be a desktop contraption at Eckerds drugstores that would do it. They only charged if you made a hardcopy of the image. But if you saved it to your flesh drive, there was no charge.