Re: CTX PL9 Blowing HOT

From: Kirk S. (crayzkirk_at_yahoo.com)
Date: 10/14/04 

Date: Thu, 14 Oct 2004 23:44:23 GMT

FWIW:

Removed the fused HOT and replaced the open resistor. Now have voltage at
the collector. Seems a bit high for the resolution I am running. On
multi-scan monitors, is the voltage to the horizontal varied depending on
the scan rate? Probably depends on the make, eh?

The HOT dies instantly so I'm thinking it has something to do with:

a) bad base drive - oscilloscope waveform looks ok however I don't know what
it should look like. It has a nice steady form that is broken up on regular
intervals.

b) bad snubber cap - .0047uF 2kv; how can I test it?

c) damper diode - passes the diode test however what does that tell me?

Of course, this is all just from reading the repairfaq. My assumptions are
likely incorrect.
"Kirk S." <crayzkirk@yahoo.com> wrote in message
news:sHzbd.5786$mR.4018@twister.rdc-kc.rr.com...
> Hi,
>
> Hope someone can help me. Got a CTX PL9 monitor just quit working. Power
> LED comes on ok and all voltages are good at SMPS. The HOT (Toshiba
> 2SC5411) was fused and during my probing, I killed the FS3KM-18A MOSFET on
> the flyback. Power supply was not coming up after I shorted it. I
replaced
> both and still had no Horizontal at the yoke. Found fusible 10 Ohm 1 watt
> resistor (R341) open and replaced. Now the HOT is fused again and R341 is
> open. Basically, I think I'm at where I was when I started only about $12
> poorer and a little wiser.
>
> I supposedly have the manual yet it is for a 1995UE and nothing matches at
> all. No schematics for the main board at all.
>
> Any ideas? I don't want to keep blowing HOTs; they aren't cheap. The
> deflection is controlled by a TDA4857PS and the voltages are within the
> range on the manual. I was also getting 0.4 vdc at the base of the HOT
> before it fused.
>
> Kirk S.
>
>