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From: agodwin@acorn.co.uk (Adrian Godwin)
Newsgroups: sci.electronics,rec.ham-radio
Subject: Help - Philips video camera
Keywords: ATV, video, Philips
Message-ID: <4305@acorn.co.uk>
Date: 5 Dec 90 15:20:28 GMT
Sender: agodwin@acorn.co.uk
Followup-To: sci.electronics
Organization: Acorn Computers Ltd, Cambridge, UK
Lines: 34

I've acquired a Philips monochrome video camera from a junk sale,
and am looking for details on connections to it. The usual suppliers
of service sheets have never heard of it - have you ?

The camera is marked '8925 002 50401' and is tube-based (Vidicon ?).
Connection is via a captive lead with a 7-pin DIN plug. The cable
contains 2 screened leads and 4 other leads. There is a 5-pin DIN socket 
mounted near the lens (perhaps for auto iris control ?). The camera is
about 6 inches long, and the circuitry is protected by an anodised 
aluminium cover. There's an orange lamp on top.
I'd guess from it's size and lens quality that it was intended for use
as a cheap security camera.

I can get composite video out of it by supplying it with 9V dc. I chose 
this value because it results in about 6.3 V on the tube heaters - seemed
like a good idea at the time... This supply also results in voltages on the 
tube neck between -50 and 300V, from an internal inverter.

The picture is reasonable, but suffers badly from after-images. I don't
know much about camera tubes, but it may be that it's being driven 
incorrectly (wrong voltages) or perhaps it's just the way these devices
are. 

I'm looking for more precise information about the power supply than my
guesswork, and confirmation that the tube is being driven at the right 
sort of level. I'd also like to know about the signals I'm not using
on the interface cable - two of them appear to be sync inputs (if I
provide them with about 4V of sync, the internal sync generators will
lock onto it) but that still leaves 2 pins unaccounted for. One appears 
to be an input, and the other an output.

Any ideas ? Or lectures on the care and feeding of camera tubes ?

-adrian


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