Hello everybody! I 'm brand new here and I'm a tv collector from Italy. I deeply love Zenith televisions and amongst the (unfortunately)few I own there is a GR 2701 digital system 3 from Heath company. I think it has a Zenith chassis. Since I bought it new many years ago (1989?)I tried in several ways to operate it on our PAL B/G 50 hz but without any luck! I connected it through a transformer stepping down 220v to suitable 117v but the problem seemed to be the mains frequency (50 hz instead of 60) and the tv remained dark. You could hear just a click when you pushed the on off switch.I injected a 60 hz signal to the power supply with an external wave generator and the set turned itself on but the picture rolled continuously from top to bottom,the color was missing and so the sound. I tried several options available on service menu but without any luck! Is there anyone there who knows if there are secret menus that could change the reception standard and the operating power supply frequency?I know tuner and if stages are quite different from european tv sets but I'd love to use it as a monitor. The set is a huge 27" console and in my opinion is really beautiful. Too bad it never worked! Thanks

the color was missing and so the sound.

Be aware that the sound IF frequency for much of Europe is 5.5Mhz instead of 4.5 in the USA. That's why no sound.

If you can input baseband video and audio into this set, use a DVD player set to NTSC mode to feed this TV set. Then it has a better chance of working.

Ok, since the set came on and you do have a some sort of picture, I think your power is ok. With a black and white picture, the picture rolling and no sound that would be normal for a 50Hz PAL signal feed into a NTSC set. The 50Hz in the broadcast signal is what is causing it to roll. You can adjust the vertical hold to stop the rolling, maybe adjust the sound cross over to maybe get sound. As to get color you would need a PAL to NTSC converter. You would need some type of tuner such as a the tuner on a VCR, Cable Box, Satellite Box, feed into the PAL/NTSC converter with RCA video cables, then from the converter into the TV with RCA cables. If the TV doesn't have RCA Type Jacks on it you would then need a RF Modulator to get the signal back onto channel 3 or 4 . If you decide to get the converter don't mess with any inside controls. Once the converter is hooked up the set should work just fine.

Thank you very much for all of those who posted a reply. Two are the problems with the suggested solutions: The set doesn't turn on without the help of a 60 hz square wave generator hooked to a pin of the digital module.
This 60 hz square wave is generated from the power supply and fed to an input of the module that contains all main processors. I think the ccu need this pulse to switch the system on. The second problem is the vertical frequency cannot be adjusted in any way since it is a digital chassis using not the traditional analogic process but d/a converters that send the signal to digital processors all controlled by the central control unit. The digital signals are then re converted to analog signal to drive the conventional stages (horizontal,vertical,piture tube module,audio power stages etc.). Basically this set is very similar to ours and "on the paper" it could be easily adapted changing the frequency of quarz oscillator . I tried several things but with no luck! I have a multistandard vcr I use to watch my favorite tv show (bewitched) on my televisions (bang&olufsen) but when I hooked it to the Heath/Zenith tv it showed a rolling picture again even if in color.
After several attempts to modify it I also damaged the digital board. Any ideas on how I could get a working one? Zenith never exported tvs to Italy so it's difficult to get parts. Many thanks.

Hmm, I would try to find a voltage adapter that would output 120 volts AC 60Hz. They are not hard to find here in the U.S. You maybe able to find one online somewhere for sale. Most of the Voltage adapters that ive have seen here can only be used overseas for lets say like 220 volts AC 50Hz into 120 volts AC 60Hz. I would think that would be the best solution for your situation. I know if I ever came across a set from Europe, I might have a hard time looking for a voltage adapter that would do 120 volts AC 60Hz into 220 volts AC 50Hz. I noticed you said you were feeding your set 117v instead of 120v. I know thats not much difference but would 3 volts make a difference. Also if you have a DVD player try putting it into NTSC mode if it has that feature and see if picture stops rolling. did your VCR display a rolling picture in color. If so, seems like your VCR is putting out a 50Hz NTSC signal instead of an 60Hz NTSC siganl. I have an old C/KU-Band Satellite dish that I use to watch the free stuff thats up on Satellite. Sometimes I can pick up signals from South America and Europe. South America uses PAL in 60Hz so any NTSC TV will display good picture but it shows up in Black and white. Broadcast from Europe will be in black and white plus the picture will roll because of the 50Hz PAL broadcast, Any set with a Vertical Hold control will fix that problem. But things are all going digital in the satellite world so NTSC/PAL problems are almost a thing of the past.