Quote:
Originally Posted by paulsherwin
It's also reasonably easy to convert a modulator from a scrap VCR...
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This is true, but there are a few drawbacks. Firstly a VTR modulator will be uncased so to you will have to find a box to put it in and drill it neatly if you want to make a tidy job of it.
Secondly many later VTRs have the modulator combined with the tuner / IF unit in a way that is difficult to seperate so you end up with a big lump of useless circuitry to perform what should be a reletively simple function.
Lastly many later VTRs have the RF output channel slection done through the machine's menu system so the modulator won't work without a companion microcontroller to provide (usually) the right I2C codes. Again it's possible but not necessarily easy. Others (e.g. some Philips) are varicap-tuned so you need a stabilised source of a doubtless inconvienient voltage to get them going.