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HP 2648 running at 50 hz

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Cocorito Pap:

I got an HP2648 terminal from the US.

I read in the manual that if you run the machine with 230V 50Hz power ( like we have in Europe ) beside changing a couple of fuses , you should also replace the display timing card crystal.
The one required is 17.5 Mhz but I am not able to find this anywhere.

What if use a crystal with a frequency close to the required one , say 17.1 Mhz ?

Would this work ?



I suspect this is just to prevent interference between the video refresh rate and the mains frequency. Personally I would try it as-is and see if it causes any problems.

Cocorito Pap:
This makes sense, thanks.

What about using a crystal with frequency close to the one required ( 17.1 Mhz for example ? ) .


What crystal is fitted for 60Hz? Frequency? Size? Cut?

17.28MHz is a fairly available in the UK, however is might not be as simple as just changing the crystal - the drive circuit is likely to be tailored to the cut of the crystal, might work, might not.

If its only for project work you could buy a cheap Chinese 60hz pure-sine inverter and run it from your bench PSU.


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