CRTs, Flea Markets

M01KKX07WB21 – mini CRT

I found this mini CRT inside a Hitachi VM-C1E camera.

Camera Overview

Camera looked clean and well maintained. It had a very interesting folding style – where the front would swivel to the right allowing you to hold the camera:

It came with the charger / power adapter and with the cable – but camera would not start nor eject the tape. I also tried powering it with my own power supply, still the same.

Opening it up

I started opening the camera up but it was a frustrating experience to get to the ViewFinder picture tube. A lot of screws but then additional latches holding the case together. I got in eventually, managing to save the tape that was still unrolled inside.

The first surprising thing was that it had no date code stamped on the inner plastics:


The electronic viewfinder was built into the back of the camera – not much flexibility for the user to just move it up. I was able to recuperate its plug (since I can clamp the source signals easier if I do so):

The EVF block seemed difficult to access to – so I had to risk when finding out the input signals. GND was connected to Flyback Transformer’s case, but VCC was hard to find since I was not having access to the bottom of the board, to the FBT’s other pins.

Probing around, I heard a little beep from the continuity checker – which indicates VCC and a charged VCC to GND capacitor. And I was able to power it on and find the Video Signal pin too:

It needs around 5.2V – 5.3V, at 5.0V the image is squished with about 2mm towards the top of the CRT. After 5.2V, the image enlarges to fill the whole screen.

But I still wanted to know what is the IC that is driving the board as well as the model of the CRT …

Maybe they were mentioned in the Service Manual ? After locating it (took few iterations, and found it on by searching Hitachi 3244E), I got one step further. The driver IC was written there – a Hitachi HA11821FP. Still the manual did not mention the model of the CRT. However, there was a diagram on how to take it from the housing!

This is where I made a mistake, when trying to unhook a plastic clamp that was keeping the neck of the CRT down. I pulled too strongly upwards and I snapped the CRT 🙁

Consolation price – I could finally see the model of the tube – M01KKX07WB21. Confirmed also that the IC is indeed the Hitachi one (although the marking on it is A11821 ):

Since the driver board is working, I decided to keep it – I have at least one EVF unit (from a different camera) where I could not salvage the driver board. Maybe I would be able to pair the two together ..

In conclusion, if somebody is curious to do the same thing, first release the front of the tiny CRT before pulling upwards from the neck (with the clamp hook pushed in). Then lift by the RCA Pins and the whole board and CRT should come upwards.

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