RCA Colortrack 2000 (CTC-131) inop.

[Red October]

Hi there! I'm new here. OK, that's out of the way.

My old RCA Colortrack 2000 set (A Thompson set...) had reached the end of its useful life. Well its picture tube had -the picture was fuzzy and badly overscanned. Consensus was time to replace the set. I visited my local TV shop and was vended an older Colortrack 2000, an American-made RCA set with a brand new picture tube. One caveat, it had to be re-assembled, as its previous owner had put it in for repair and declined to collect it, so it was left un-assembled with the new picture tube. The repairman did most of the connection (not that it was necessary; everything in the set is keyed) and left me to put the speakers back and re-asseble it. Upon doing so, however, it cannot be brought to life. Nothing happens when it is plugged in and the power switch is pressed, nor when I attempt to power it up with a remote. The Chassis is CTC-131; it is the big heavy model in the wooden cabinet; very similar to the Dimensia monitors and the Lyceum commercial sets. Anyway, I have the service print, but it is rather useless as it is simply prints of the circuit cards and has no trouble-shooting info or anything of the like.

The fuse and line cord are good.

[Krankshaft]

Re: RCA Colortrack 2000 (CTC-131) inop.

Check the horizontal output transistor.

If that checks out ok check the flyback transformer.

These are the two most common reasons for the high voltage power supply not coming on. Without the HV any TV new or old will be dead in the water.

If both are ok check for voltage from the standby power supply older TVs used a linear transformer for this and newer TVs use a switching supply which have their own chopper transistor, transformer, and rectifier.

[Red October]

Re: RCA Colortrack 2000 (CTC-131) inop.

I'm affraid I don't know where to check for these things; the "service manual" I have is a relatively useless schematic diagram with absolutely no troubleshooting information and little clarification. While I have lots of experience in electronics repair I have never tackled a television set before, so I don't know specifically what to test those parts for.

[kc8adu]

Re: RCA Colortrack 2000 (CTC-131) inop.

sounds like missing standby voltage or problem in the tuner controll module.
iirc that has 2 big boxes to the left.
bad solder joints in both are common.

[Red October]

Re: RCA Colortrack 2000 (CTC-131) inop.

Yeah, that's about the only info I've been able to find on-line, given how common the CTC-131 seems to be (I've seen loads of them, including the rare Dimensia and rarer Lyceium (which I had an opportunity to acquire once but had to pass simply because I couldn't shift the bloody thing... The chassis is a mix of real wood and chipboard and they beat the 21" "Sony Design" monitors for most deceptively heavy TV set; the latter being propper nut-busters but at least equipped with handles). Anyway, back to the set in question, it will not power up with a remote as well and the power switch tests good with a meter... would bad solder joints in the control module make it unresponsive to the remote as well? Where should I check the standby voltage and what should it be, and will it be AC or DC? I have the scematic drawings.

[Krankshaft]

Re: RCA Colortrack 2000 (CTC-131) inop.

If its a bad solder joint get ready to get out your magnifying glass and spend some time with the board.

As for checking the standby voltage you should check at the standby transformer trace the secondary wires and test there you should also find a voltage at the power switch as well.

[Red October]

Re: RCA Colortrack 2000 (CTC-131) inop.

OK I did some more basic tests, there is 5 volts at the power switch, as far as I can tell, and there is 167 volts at the capacitor and boy does it make a big blue spark if you screw up with the meter leads. The leads to the controls are wrapped and seemed to be wrapped well, not soldered.

[Krankshaft]

Re: RCA Colortrack 2000 (CTC-131) inop.

Ok disconnect the TV and measure the Horizontal Output Transistor for shorts bad HV parts is the most common reason for a TV not starting up.

The HOT will be on a large heatsink and its usually near the flyback to confirm it is the HOT.

Sometimes they are in a plastic case secured to a heatsink with one screw and other times they are in a metal case secured to a heatsink with 2 screws.

Take the number off of the transistor and look it up at alldatasheet.com. HOTs are specifically made for TVs and they aren't garden variety bipolars so when you find the data sheet it will say horizontal output transistor on the sheet.

Anyhow set your multimeter to the diode check function and measure from base to collector in both directions you should only read a number on your meter in one direction. Do the same from base to emitter again get the datasheet from the site above for the pinout.

This is a common failure item and its best if you test this now so we can move on if its not to blame.

[kc8adu]

Re: RCA Colortrack 2000 (CTC-131) inop.

if the hot was bad that one would blow the fuse.
disconnect the keypad and try the remote.
years of dust,smoking grunge,and windex cause the switches to get leaky.
locks up the micro.
since you have +5 and main b+ its either keypad,solder joints,or a dead micro.
if the micro was running the degaussing relay would click twice each power on.

[Red October]

Re: RCA Colortrack 2000 (CTC-131) inop.

Well I tried disconnecting both keypads and using the remote, no joy there. I tried disconnecting the remote sensor and using the keypad. No luck there either. RCA remote frequencies are rather sensitive to certain light, though, they do NOT enjoy floursecent lighthing at all. So would this most likely be a bad micro?

[Wizard]

Re: RCA Colortrack 2000 (CTC-131) inop.

CTC131 is nasty chassis to work on. Basketful of wires, and hot chassis etc.

SCR chopper regulator for B+ working off horizontal frequency, flyback transformer sometimes fail and take out the horizontal transistor and the SCR. There are another issue that makes powering up a problem with MTT module (the metal box standing upright with bad capacitors and solder joints, solder the wires on the metal pins).

Cheers, Wizard

[Red October]

Re: RCA Colortrack 2000 (CTC-131) inop.

Well I've had the micros worked over by a tech, and I've gotten some things to look for. Progress is being made on this set. Funny what you mention, Wizard, a veteran RCA tech told me it's NOT a hot chassis, and it definitely seems easy to work on, certainly by today's standards of one-board don't-even-bother sets.

[Krankshaft]

Re: RCA Colortrack 2000 (CTC-131) inop.

I disagree I'd much rather work on a modern all on one IC set then these overbloated monsters .

Keep us posted when you get the set running.

[gonzo0815]

Re: RCA Colortrack 2000 (CTC-131) inop.

If you keep some pic`s or a memo, it is not that overly complicated to work on those older systems, where everything where on their own pcb.
But sure, compared to a modern chassis where you have one or two pcb`s and may be five cables it is actually some work to handle it and don`t mess it up.

Fixed recently a Thomson ICC20 100Hz set, and i was very surprised how less components they have used (well, i only have fixed a very old Grundig Pal Plus 100hz unit (CUC 1981) all other sets where actually 50Hz analog circuits.

[Wizard]

Re: RCA Colortrack 2000 (CTC-131) inop.

I'll check the 131 service manual to remind me.

BTW, I worked on lot of 130 so I know. Often RCA reuse part of it into another till CTC17x where it went digital.

Oh, with proper service manual you can adjust a knobless chassis. But I regard Toshiba the WORST. I lost so much of settings by simply scrolling from beginning to the last and there is no "hard" stop, when I incremented to look through different selections steps from bottom to top (example 80 to 1), reset occurred.

Cheers, Wizard

[Wizard]

Re: RCA Colortrack 2000 (CTC-131) inop.

Confirmed.

RCA reused MTT module idea. The standby power goes inside the module, check big caps inside MTT and resolder all pins (including wire wrap posts and solder wires to the posts them selves). This is where microcontroller and tuner resides in one box.

Ok, Check Q401 (power chopper for transformer), Q404 for horizontal circuit and
change all small electrolytics around the U101 for the chopper 220uF, 1uF and 2.2uF and another 1uF that is the coupling cap to the base of Q401 chopper. Resolder rest of bad joints on the chassis iteslf. The U101 is the regulator that is in sync from HV transformer pulses to keep power supply and horizontal circuit in sync at 15.7KHz.

Vertical is discrete and part of it drives the pincushion circuit for the horizontal deflection as well.

Cheers, Wizard