1975 RCA XL100 model CU 680 W trips reset button when turned on
 

Red reset button trips when power knob is pulled out. Reset and does it again. Where should I begin looking? Interested in fixing up and using with Atari games.

Remove the power supply diode board, reset the breaker and see if it holds and the channel light comes on. If it does, check all nine diodes on the little board. If diodes all check good then there's a short on one of the B+ supplies. Large filter cans, vertical or horizontal SCR issues were common. Can remove the SCR mounting screws to check them without actually having to pull them out of their sockets.

Sounds good, I'll check it out soon as I can get around in here. I've got stuff scattered everywhere.

If you find a shorted diode, change the other three in the same bridge grouping. I believe there are two full wave bridges on that small card, plus another diode that never shorts.

Those are standard recovery diodes, so any typical rectifier like the ECG 125 will work fine.

John

Great, ty🙂

Restoration begun on this set. I've managed to get the entire outside done. Now if I can ever get inside and begin with repairs.

Is that the model with those miserable little sliders behind the door?

John

Cabinet looks great.

Thank you. Yeah it has the 4:sliders for contrast, etc.

The controls are usually good, but those little chromed plastic sliders like to break. If you have to adjust them, try to push them at the base of the slider instead of using your fingertip at the top of the slider. Takes the torque off them.

I used to buy them 50 at a shot back in the day.


John

These are still intact and move without a problem. I'll still watch out for them. Can't wait to get this up and running. I plan on using Atari games on it.

Very nice set.

Ty🙂

If power supply checks ok don't overlook the trace/retrace SCRs

Ok👌

And if you find a shorted SCR, carefully check the reactance transformer connections on the back side of the board or cracks in the board traces from mishandling. I remember we had one brand new out of the box that had a cracked sweep board.

Also, the sockets themselves could get iffy after many years and hours. Flush them thoroughly with a circuit board cleaner and re-pinch the pins with a sharp awl.



John

If it is cracked, then what? I doubt there's a replacement after this long 😔

Cracks in PWB's I have fixed with super glue, solder-bridge the board traces using 18-20 ga/ solid copper wire. While these were pretty good when new, they always responded well to simply cleaning module sockets and controls, looking for solder issues usually turned up a few broken joints under heavy parts like pincushion transformers, etc.

I have modules for this XL-100 series. I scrapped a few back in the day but only with good cause like a broken CRT. Moyer's Electronics still has a surprising number of RCA parts too.

Awesome, I'll keep in mind.

Good luck. I hope you get that TV working as normal, as they were good sets and make excellent pictures when they are working as they should. Get yours working as normal and you will have one excellent TV; they don't make 'em like that anymore. When I was in high school 48 years ago (!), I was on the AV crew. Our closed-circuit TV setup had one RCA color monitor, 21-inch if I recall correctly, with the new RCA logo, not the old round one (for our school's CCTV system, we had Sony VTRs and modulators on channels 2, 4, 6 and 7, between locals 3, 5 and 8. We used old Sony 5-inch b&w TVs as monitors for two channels (4 and 6), with a 19" Zenith b&w for channel 2; channel 7 was our one and only color channel, which we began using in my senior year. Don't know what's in use there today; probably flat screens.

Ah, yes, those were the days.

Awesome. Ill do my best. I want to use it with my rca selectavision units and ced discs when done.