Citizen 2400-10 – mini CRT

Found this mini CRT inside a Sony CCD-F385E Video Camera, but the driver board of the Electronic View Finder unit needed some new capacitors (and brightness adjust after).

Camera

Camera came in a bag (rather tedious to carry from the flea market back home), with two batteries (which will go directly to the Recypark), with the original charger, remote and with the RFU-90E AV adapter.

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Camera bag is nice with lots of paddings, unfortunately black dust everywhere from the disintegrating microphone sponge foam.

Camera itself looked nice and complete (except of course the mic cover which seem to decompose in time):

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The accessories inside:

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Having a look inside the Remote Control was a turn off. I could not take the battery cover off, it looked jammed. I had to pull it apart almost breaking the entire case and surprise surprise, batteries leaked so badly that the discharge hardened like a glue.

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I’ve tried powering on the camera with the Power Brick and its battery adapter, and although the camera turned on (and I could see the lens rotate trying to focus), there was absolutely no image on the viewfinder..

To dismantle the camera was rather straightforward – no hidden catches.

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Thankfully, the plug where the EVF flat cable was connecting was a through hole type, would would allow signal connection much easier once the EVF unit is taken out of the camera. So I decided to de-solder it:

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Electronic View Finder

Opening the EVF unit is a must when trying to locate the signal pins (at least VCC, GND and Video In). At first view, the CRT is a model CITIZEN 2400-10.

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On a closer look, another marking is visible, although I had to take few pics to try to put it together:

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An interesting tidbit is that the service manual (that I found online here) has a typo when it comes to the name of the part. The letter ‘O’ (from Oscar) is reported as ‘9’ : M91JY260WB:

As you can see in the photos above, the one on the CRT is ‘O’. However, I doubt anybody is on the lookout for this CRT as a spare part 🙂

Driver board issues

To identify the input pins (at least VCC and GND) is easy, GND is the PIN connected directly to the case of the Fly Back Transformer and few of the pins of the FBT are also connected directly to VCC (but to nothing else).

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The CRT exhibited the same behavior as inside the camera, no image. This is where I started investigating the driver board a little closer. It was another case of ‘creme caramel’ board, as the left side solder connections all were dull – and the top part all brown:

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I decided to measure the capacitors in circuit using the Atlas ESR70 plus meter:

As you can see, the two ELNA capacitors (yellow ones) were bad.

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I have measured the other capacitors (ESR / in circuit) and they were reporting OK, so I decided not to change them. Also, for the 82uF @ 6.3V (105C) I did not have a exact replacement, I have used a 100uF @ 10V (85C) (is the smaller one in the photo above).

The effort payed off and the CRT is alive :). Forgot to mention that the driver IC is AN2512S and that it seems to be the sharpest at 5.2V (drawing 74mA).

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One more addition to the collection!