RCA projection tv power issue

[freakaftr8]

Hey all,

My father in law has this RCA projection tv with a build date of Aug 1994. Chassis PTK169PGA Model P46731AT. It's dead, the only thing I get is when I plug the set in, I can hear 10 quick blips from the power supply, then nothing.

Now this set has been blowing fuses in the past. Looked for burned resistors representing a bad tripler, but cannot see anything fried... Does anyone have an idea? I have no schematics on this set, so Im really kinda stick.

Thanks!

[radiotvnut]

The B+ is probably too high. Normal B+ for these sets is around 140 volts. There are 3 caps in the power supply that you need to change. IIRC, they are a 39uf, 2.2uf, and 15 uf. You can use a 47uf in place of the 39uf. They are located on the right front corner of the main chassis. There will be an IC and a transistor mounted on a heatsink in the area where the caps are. Also, check the chopper transistor (the one mounted on the heatsink) for a short. If it's shorted, the IC is probably bad as well.

One last thing (which should probably be first on the list). Check the horizontal output transistor for a short. If it's shorted, there is a blue cap located close to the transistor that may be swollen.

But, whatever you do, replace those electrolytics in the power supply!

[freakaftr8]

Ah sweet! Ill check into these components! Thanks!

[kx250rider]

There was a kit for that power supply, which includes the caps that Radiotvnut mentioned, and also the IC and several transistors, diodes, and resistors. One of the caps is a weird non-polarized electrolytic. Being out of the business for over 5 years, I can't say if they still have that kit. It was an aftermarket kit, which was available at places like Mat Electronics, and Fox International. Maybe someone else will know who has it. If you want the kit and can't find it, I have one left over "for a rainy day". I would prefer to keep it since I have several friends with those 169s, but I would be happy to itemize the kit for you.

The bad possibility is that the HVR block is shot. That's nearly as common as the VIPUR (power supply in those RCAs) being blown. Those aren't available anymore from RCA, but I heard that there are aftermarket ones that work fine.

Also, if you haven't noticed, it's EASY to remove the whole chassis box on those sets so you don't have to lie on your stomach to work on the set, as you do with most other big screens of that age. There are 2 long wood screws on the sides of the particle board chassis housing that hold it to the cabinet. You remove the speaker grille, unplug the control panel, and slip the whole chassis out, tubes and all

Charles

[radiotvnut]

If you have to change that HV block, try to find a NOS RCA. I've had problems with cheap generics going bad after short periods of time. I think www.matelectronics.com still has that 169 power supply kit. That 169 chassis was a good one and was used in many direct view and projection models.

One other thought, I've seen the audio output IC short and cause the set to shutdown.

[rcaman]

we use hr demien replacements for the high volt splitter. not a callback yet they make great flybacks also. the rca splitter # is 205064 check for a shorted horiz. output 2sd1885 it will short when the b+ has been running high for a while. steve