need zenith ps2 screen help

[atarihacker]

can the zenith screens built in Voltage regulator handle the step down fro 12v to 7.2v and if possible can some one post a picture of where the voltage regulator is on the Zenith screen pcb
and can some one tell me how to wire the voltage regulator
Its for my unmodified system GCp
thanks

[Chapel]

Not positive, so I hope someone can confirm this, but I think the voltage regulator is on a secondary board which is also connected to two caps, a resistor and the power LED.

[Ben Cebhrem]

I can confirm this, but without looking at the pinout, I've had that little board put out 12v. The transformer puts out 13.5v, despite saying 7.5v.

I've you still the parts, please do check, it's bizarre. The regulator is a 4 pin chip, similar in appearance to a 3 pin. It's covered by white plastic blocks though, so I haven't yet looked up what kind of regulator it is exactly.

[Chapel]

I can confirm this, but without looking at the pinout, I've had that little board put out 12v. The transformer puts out 13.5v, despite saying 7.5v.

I've you still the parts, please do check, it's bizarre. The regulator is a 4 pin chip, similar in appearance to a 3 pin. It's covered by white plastic blocks though, so I haven't yet looked up what kind of regulator it is exactly.

Unfortunately I have already cut back most of the wires on my Zenith and can't reliably hook up the screen/voltage regulator to power until my battery comes in. However, I can check the AC-DC Highway to... I mean... converter to see if it is really putting out 13.5 instead of 7.5. That would be strange.

[Ben Cebhrem]

Aye it is odd. The converter that is held in the base is putting out 12v btw; it's the transformer/adapter that gives off 13.5v. This has held true, for me at least, with 3 xBox Zenith screens.

[Chapel]

Aye it is odd. The converter that is held in the base is putting out 12v btw; it's the transformer/adapter that gives off 13.5v. This has held true, for me at least, with 3 xBox Zenith screens.

So does this mean that feeding it 7.5V DC won't work?

[Ben Cebhrem]

Don't know for sure yet, as I have not tried it. I can't see why it wouldn't work though.

[Chapel]

Well, I guess we will find out then.

[Ben Cebhrem]

Okay, just took apart that little board, and it turns out the regulator is supposed to be an 8v +/- .2v regulator. How I was getting 12v, I don't know, but I'll make a diagram and post it if somebody can make sense of it (as I can't make sense of electronic digrams, other than building them).

Good luck mate.

[gzidude]

Last year I took that little circuit board you guys are talking about and drew up it's schematic. I actually did it from scratch 3 times to see if I was doing it wrong because I can't figure out why that big resistor is connected the way it is.

http://www.geocities.com/sketyro/zenith ... _board.pdf

[gzidude]

If you use that schematic, correct the error I made in it. The 220 ohm resistor is really a 2.2K ohm.

Right now, I am in the middle of rewiring that little board, the video and sound inputs, the external power supply connection, and the on/off switch into a single board. I rebuilt it from scratch, buying some new capacitors and a new power regulator chip. I tested it and it works as it should, with the above correction.

Also, I measured 11.1 volts DC out of my new circuit. Correct me if I'm wrong, and I may very well be, I believe it is normal to output a higher voltage when the load is not connected. I've seen such a thing before, but I do not remember the circumstances.