RCA ColorTrak 2000 (CTC 158B) won't power on.

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Okay just put the probes on the emitter and collector of the HOT, with my multimeter on the diode setting, and I get 0 volts either way. Testing on the resistance setting gives me 1.6 ohms.

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

if your reading Emitter to Collector and getting 1.6 ohms your Horz Output is bad,you will need to remove the Horz Output and again reread out circuit if you again get 1.6 ohms from Emitter-Collector transistor is bad

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Would a bad HOT cause the resistor and SCR to fry?

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

yes,also when you remove your Horz output out of circuit reading the Emitter connection which is same point as your HOT gnd to the Collector connection in set you should have a very high resistance reading

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Okay, getting infinite ohms when testing the HOT out of circuit. Switching polarity, and I get 7.1 mega ohms. Testing the emitter and collecter points on the chassis, I'm getting only 1.7 ohms.

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

OK you have a short some where on the 150 volt line cause the 1.7 ohm reading I'll need to look at schematic Monday @ work to now see what could be causing the short to HOT ground

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Found a ctc156/157 schematic for you very similar to the ctc158 except for some component value differences but theory is same

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

looking at page 5 of the schematic showing Q4401 horz output collector ties to pin 11 of t4401 from there it goes up to yoke connector E4401/E4402,with you meter on resistance scale negative probe to HOT gnd Positive probe to collector connection in set disconnect the Horz yoke plug E4401/E4402 @ yoke and see if your short goes away NOTE!!! this is done with your Horz output transistor removed from set

Now if short goes away then our problem causing the 1.7 ohm short is in the yoke return area
Now if short still there after removing the yoke plug,then go back to the SCR and remove that from circuit and see if then your 1.7 ohm short goes away from same connections used as above

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Okay I assume by horizontal yoke plug, you mean one of the two connectors on the yoke of the CRT. Disconnected both, tested, and still getting 1.7 ohms.

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

yes that's correct now you need to remove the scr and see if short goes away

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Okay with the SCR removed and the yoke unplugged, still getting 1.7 ohms.

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

ok look at your schematic see pin 2 t4401 goes down to the tp4007 which is same point as C4007 cap look in that area make sure no short to HOT gnd there again make sure no diodes cr4001-cr4004 are shorted make sure your resistor installed not shorting to anything

now if everything looks good there go back to where SCR area at look for cr4102 make sure that diode is not shorted

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

I think T4401 is shorted.

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

why do think that?

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

TV fails, takes out the resistor and SCR. I replace with a new SCR and a bigger resistor and it kills the fuse and probably fries the resistor. With the yoke disconnected, what else is on that 150 volt line that could short?

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

i don't see anywhere that T4401 could short cuasing 1.7 ohm to HOT gnd reading

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

did you go back to SCR and check cr4102 for a short?

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Nope, it's not shorted.

I think it's time to look at this objectively. I don't know what failed on this, but it's sounding like it's going to be something more then a common resistor or diode. I'm thinking the flyback or something else that's both pricey and hard to find. I already sank $15 into trying to fix this, and being nearly flat broke, $15 is a lot of money right now.

Also factoring that I can likely find a working regular TV for free nowadays, I think it's time to give up on this one. I hate to pitch it, but I have other things I should be working on and sinking more time and money into a TV that few besides me care about is not wise.

Thanks for all the help Ron. I'm just happy that I found out enough about the problem to make a decision on it, rather then leave it sitting, taking up space and collecting dust.

[RON_CET]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Glad i was able to offer some help, have good weekend

[Mrx3750]

Re: RCA ColorTrak 2000 (CTC 158B) won't power on.

Well this is an ironic twist of fate! I think I just found the problem!

When I give up trying to fix something, I start salvaging components to have on hand for other things.

This of course includes capacitors, since lots of times they're fine, and of high quality, especially in the older electronics.

The 33uf 200 volt capacitor is testing at less then 1uf capacitance!

This pisses me off because it's not bulged, obviously, it's not leaking, and it's a Nichicon capacitor! I didn't even suspect that would be the culprit especially since when I tested it a few years ago, it tested perfectly in spec, so I left it in place.

And it's too late to save the chassis.

Edit: Looks like it leaked a tiny bit around the bung, not enough to be noticed. I got screwed over by a Nichicon!