JVC Camcorder (1994)

This is a JVC VHS-C camcorder from 1994 model no. GR-AX404Not any camcorder but according to the sticker the official Camcorder of the the 1994 world cup USA 🙂  (Not a great world cup from my recollection, England did not even qualify, and the final between Brazil and Italy was a scoreless draw with Brazil winning the penalty shootout.)

 

 

Here is the the front and the rear showing the cassette loading.

This Camcorder uses the VHS-C cassette.  What was pretty nifty about this standard is the tape width was the same as standard VHS, and you could get an adapter that allowed you to play the VHS-C tapes in any VHS player

 

 

And the last image before digging into the teardown is the base label showing it was manufactured in March 1994.

 

 

 

Viewfinder

The unit is assembled together with a lot of 5mm philips screws, I counted 50+ screws removed from the casing and other plastic parts alone. The top part removed allows you to remove the viewfinder.

The eyepiece containing a focusing lens can be pulled off and unscrewing a couple more philips screws and the two pieces of plastic can be separated to reveal the contents.

 

 

I don’t know why but I was surprised that the viewfinder is actually a miniature CRT (Cathode Ray Tube).  It is interesting to me how fast the CRT became obsolete. From 1960’s-1990’s they were ubiquitous. In the last 10 years they have pretty much completly disappeared.

This is the front and back views of the viewfinder board with the high tension coil box on the leftand a single 16pin chip (BA7149F) on the rear of the board which might be a deflection coil driver.The (black and white) CRT has a small 8 x 10mm screen, the is magnified by a focusing lens in the end of the eyepiece. The CRT has four wires going to the cathode, and four wires to the deflection coils and the high tension wire that connects to the front to the tube under the screen surround

Removing the cathode connector, and unscrewing the clamp and you can unscrew four plastic nuts, of which two contain permanent magnets. Removing a plastic shell reveals the scan selection coils.

CRT Scan deflection coils

And this is the individual coils un-clipped and removed

And then you are left with the bare tube, I cannot go any further without smashing glass.

I decapped the 16 pin BA7149F chip on the viewfinder board.  The die marks are TB-103, but I cannot find any documentation for this chip. I think it is definitely a driver chip with two prominent drive transistors clearly visible.

The chip is made in a two metal (Aluminum) large geometry ~3μm Bipolar process.  One thing that jumps out under the microscope but may not be obvious from the image is the lack of die seal and scribe lane silicon visible.  Normal (Modern) chips the die edges are defined with a wide metal track (The die seal) the die are spaced out by 50-100μm and the saw blade used to separate the die is ~30μm wide, so when separated the die normally have ~5-10μm of overhanging scribe lane visible.  This die has next to nothing just ~1μm before the transition to (purple) oxide.

Nose Cone

Next I removed the front or nose cone plastic

This contains a manual iris lens cover, the imaging mode selector, and a microphone. This is the microphone assembly.

The microphone sensor is at the bottom, the board a bit oddly just holds a single diode on the back

Also contained within the nose area attached to the body is a small board with infrared LED and detector, used as a rangefinder.

As I already have a lot of images in this post and there is still loads more to look at I am going to stop here and break this into two (Or three) parts.

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