Can someone identify this NTSC video (CRT) monitor problem? Is it simple?

This is likely a bad electrolytic in the field output circuit. Not a difficult repair.

By the way:

The model number is Panas> > Hello all.. I have a monitor that allows viewing of the retrace and

Very common, there are bad capacitors in the vertical deflection amplifier. There may be a number of these that have to be changed. They can be easily verified with an ESR meter. To service this, it is best to have experience in TV service.

Jerry G..

--

On Fri, 9 Jan 2009 13:02:20 -0800 (PST), " snipped-for-privacy@gmail.com" put finger to keyboard and composed:

I'm not familiar with your monitor, but in general you would locate the 4-wire cable that connects to the deflection yoke around the picture tube. The two thinnest wires would connect to a vertical amplifier IC on the PCB. Since yours is a Panasonic monitor, I would expect that this IC would be made by Matsushita and would have a part number beginning with AN. These ICs are often in a SIP package and are attached to a heatsink. Some designs use a pair of discrete transistors, also mounted on heatsinks. I'd replace all the electrolytic capacitors in the vicinity of this IC, and I'd also reflow its solder joints.

- Franc Zabkar

I've been going by the canonical repair faq.. and reading through it for the umpteenth time I discovered a mention of "vertical foldover." I hadn't seen that before. Is this what's going on in that photo?

Also thank you F.Z., I probably can't screw it up with advice that clear.

On Tue, 13 Jan 2009 10:02:33 -0800 (PST), " snipped-for-privacy@gmail.com" put finger to keyboard and composed:

That's one common symptom of bad caps, another is vertical non-linearity. You may also see retrace lines and/or digital teletext data (lines of dots) during the vertical retrace interval.

If you can identify the vertical output IC, then you may find an application circuit in its datasheet.

You can search for datasheets here:

- Franc Zabkar

Monitor's fixed. Thanks to everyone!

e:

BTW the repair manual for the monitor is $4.25, plus $9 shipping from this company:

I'm not sure, but I think Panasonic wants $3.01 for it, but with shipping it could be more.

Two days ago, my Sanyo TV had a similar problem. Most of the vertical capacitors (all Jamicon brand) measured high ESR but normal capacitance.

On Fri, 16 Jan 2009 07:08:43 -0800 (PST), " snipped-for-privacy@gmail.com" put finger to keyboard and composed:

The sci.electronics.repair FAQ states that ...

"[Vertical foldover] is probably caused by a fault in the flyback portion of the vertical deflection circuit - a charge pump that generates a high voltage spike to return the beam to the top of the screen."

The cap between pins 4 and 8 of the AN5512 IC is indeed a "flyback" charge pump cap.

See page 3 of the datasheet:

- Franc Zabkar