I am going to try to repair this for a friend.
I always expect the flyback in these new style cheap sets but this one starts up with high voltage for about a half second and shuts down. Probably not full HV but the static sound happens and the CRT gets a little charge on the first press of power button. Then every press of power button afterwards has the set seaming to start up for a fraction of a second with the speakers sounding a solid: "bump bump". I'm thinking maybe a diode is shorted shutting it down or an electrolytic is weak preventing correct voltage somewhere. One of the big sand resistors(measures 998ohms in circuit) near the AC power cord stays hot when set is off. I guess thats normal? I have no schematic so I wondered if some kind soul recognizes that specific symptom. I think the set has had low hours so hopefully I can repair it.
Thanks very much,
John

When the EEPROM gets corrupted due to bad tuner grounds the horizontal frequency setting can get changed to a very low value leading to shutdown. Try another EEPROM to be sure. You may be able to get it to run by powering it from a variac at reduced voltage (this might not work since the 185 has a switching power supply). If that doesn't work, I think increasing the capacitance from the C to E of the HOT will lower the HV and prevent shutdown. Once the set it running, you can go into the serive menu and readjust the horizontal frequency.

the tuner grounds in the 185 chassis are rock solid i cant remember ever doing one. and i do a ton of rca. the 175-177 were bad. i would check the diodes off the fly for starters and look for buldging cap. since you have no schematic i can email you one monday if you want. just pm me.
your high volt could be going sky hi causing the set to shut down. check the 1600 volt cap and see if it is open. just a guess steve

the big sand resistor will be warn whenever the set is plugged in. remember the power supply is always in standby with some run supplys operating. you have to have power for the remote sensor. steve

I don't have an EEPROM or a Variac. The hurricane took some stuff. I did find 2 large solder breaks along the tuner case and at a center post for the cover all on the bottom of chassis. I used my Weller 8200-N gun(I know, it's way too big!) to resolder and dripped a blob across C325(I think that's the right #), a micro cap in the tuner section on the bottom of chassis. When I scraped the solder off it took one of the top side solder areas off but appeared to be connected on the side. I guess it'll be ok?
I then installed a motor speed control from a Honeywell Elmo projector on the AC line. With the pot adjusted to 2/3 power the set comes on and seems to work great! Picture looks great and the channels function well so I guess that tuner micro cap is ok?
Next, I proceeded to read through info on programming the EEPROM's horiz freq but I need much more info. I usually service older stuff so this part is a challenge for me. I entered the "76" code and went to category "1"(horizAFC?) and tried the recommended "13" but it made no change that I could tell and I forgot what number it was set at originally. I then accidently pressed the channel/volume buttons too fast and I suspect I may have changed another adjustment or two in the process. I pressed the menu button three or more times in the process and caused the screen to display a bright vertical line before shut down and self start up bringing me to worry I may have burnt the CRT a center line. I guess it survived.
I hope to find some programming code chart to get these various adjustments correct and verify the procedure to do it. So far the set operates just as it did before I messed the service menu codes up.
Thank you very much for the help!

I figured out the service adjustments and it is easy afterall but the code chart I found for the 177 seems to be different for the 185 as when I enter "76" and then "1" which has adjustment from 1 to 15 it seems to do nothing where ever I set it. I go to "2" and it does vertical instead of horiz like the 177 chart says. So, the set won't come on unless I put AC voltage to no more than 107v. Andy's advice helped me get this far and I can't find a CTC185 code chart. I guess I need to change the horiz freq to get the set to start at normal voltage? It plays great at low voltage but I need to plug it in the wall and have it come on! Can anybody tell me how to change the horiz freq on the CTC185?
Thanks, John

I'm almost sure the 185 uses the same service menu adjustments as the earlier ones. The first one should be for horizontal frequency. Horizontal sync will be disabled when it's on the horizontal frequency adjustment. If the picture is in sync, then this isn't the problem. It would be way out of sync if the horizontal frequency was off. I would suspect a problem with the power supply regulation if it runs at reduced voltage. Check the regulated B+ voltage. The menu button is supposed to collapse the picture into a horizontal line like the service switch on an old TV. You won't be able to burn a direct view CRT unless you leave it like that for a long time.

With the line voltage reduced to 107AC The set operates normally but with full voltage it just clicks a couple times and shuts down

I don't have a schematic but the back of the set has TP voltages so I have found that when the set is on I have about 33DC on the +23 run and 190DC on the +100 supply. I suspect the problem is all from the +100 supply being way too high. I traced the circuit board and it looks like the culprit is the HOT giving too much voltage. I am hoping something is causing the HOT to put out too much. Does that sound familiar to anybody?

Thanks, John

It sounds like you have a problem with the B+ regulator. It's definitely not the HOT that's causing the problem. Are you measuring those voltages with the set running, or is that after it shuts down? If it's not running, some voltages will be high due to no load on them. Try measuring the voltages with it on the variac set to the highest voltage that allows it to run. If the regulated B+ is a little high, the problem is in that circuit. Did you run the set with a signal to see if it was in sync?

Ok, you have a bad regulator(MOSFET ) transistor. Now, on the Right side of the chassis, you will see a long, thick sink, near the big resistor. On it will be a transistor. It is most likely shorted. you can use an IRF-740 to replace it..... hopefully, it has not taken out any parts near it. most often only the FET is bad.


BUT... do NOT stop there!!

Most likely, ther will be a little electrolytic cap, in the ckt. where that reg. is. (1/50volt,or such). it WILL need to be replaced..... OR... your FET will last less than 30 min!!

BTW-- I HAVE had to do the grounds on the 185 and a LOT of the inner connections in the TOB area. (tuner on board). Also, a couple of diodes off of the fly like to go bad (and check good) along with a cap (SMD) near the EEPROM, that will mess up the reset line, causing a dead set. Fly's sometimes go bad on that set... BTW-- when you get done, resolder the horiz. driver transformer and the little coil off of it, to the base of the horiz. output.

I didnt' read all the other answers (in a hurry to leave for the bank)... If not already suggested, R4104 in the power supply perhaps? That causes weird startup problems. It will measure OK with a VOM, but goes up in value in the circuit. It's in CTC-175, 6, & 7 if I recall. It's a 1/8 watt, and I think about a meg. Been 3 years since I worked on "new junk", so I am a bit foggy. And the eEprom INDEED will cause that too. And don't forget to pull the bottom can off the tuner and resolder ALL the places where the upper can is soldered to the PC board.

Charles

There is a regulator kit for this chassis.Common problem due to the electrolytic capacitor.The kit replaces it with a mylar cap and also a new regulator FET and some upgrades for some diodes.You must change all the parts in the kit.Part no.231523.Any RCA distributor will stock it.Also MCM and MAT have it.

Well, I have tried the advice given and I appreciate everbody's time but I am stumped. I should obtain a schematic but I usually never mess with this type of newer set and I thought it would be simple since I get it to run perfect with low line voltage.
If someone could review the schematic for me I would appreciate it. I will be posting some good photos of my Motorola and RCA combos restorations soon to try to return the favor. If everybody is too busy I would understand.
After I read the previous advice I thought the regulator kit makes alot of sense but I was not sure where to get it soon and I just pulled the regulator which is an SCR and it seemed to not be shorted but I forget the ohm meter check for it so I tried a similar SCR which functioned the same in the set. So, I tried checking various components for shorts and pulled resistors and pulled R136 which connects a HOT line to U103(U4103 on set back info) The set functions the same way when R136 and U103 are removed so I looked for somthing on those lines that is shorted and can find nothing. I want to throw the set away but it works so good. If anybody could advise I will be appreciative.
Thanks John

From the service manual for the CTC185:

Main Power Supply
The power supply in the CTC 185 is a non-isolating
modified buck converter. It uses a winding on the IHVT to
provide a voltage boost and a series PWM controlled
MOSFET to regulate the output voltage to 130 volts DC. The
supply has no alignments since it uses a precision 1% voltage
reference IC. The control circuit is synced to the horizontal
oscillator by using a flyback pulse as a timing reference for the
sawtooth ramp generator. When the chassis is in standby
mode the MOSFET is kept on by a drain to gate resistor which
forces the output voltage to be equal to the RAW B+ voltage.
The winding on the IHVT sums an inverted retrace pulse on
the RAW B+ voltage. This provides the pre-boost so the
supply will regulate even when RAW B+ falls below 130
volts. The number of turns on winding WI determines the
lowest voltage at which the supply will regulate. The 25 and
27 inch chassis regulate down to 95 volts ac and the 19 and 20
inch chassis regulate to 90 volts.
Raw B+ comes from a full wave bridge rectifier and filter
capacitor C4007. R4172 is a bleeder to discharge C4007
when the AC power is disconnected. Capacitors C4104,
C4122, C4124, C4134, and C4135 are for RFI suppression.
R4146 and C4137 form a snubber for MOSFET Q4114.
R4103 is a current limit resistor for Q4114. It limits the gate
drive by reducing the 9 volt gate supply with respect to the
source terminal of Q4114. R4108 provides gate drive when
the chassis is in standby. CR4106 is a protection diode for the
gate of Q4114.
The 9 volt gate supply consists of C4106 and CR41 I 1. The
charge pump is C4138, R4147, CR4113 and CR4112. C4138
is charged through CR4112 during retrace, and discharged
into C4106 during trace through CR4113. MOSFET Q4114

is switched on though R4138 and is turned off by Q4113
turning on and bleeding the gate charge off through R4114.
The comparator block consists of Q4102 and Q4103. The
inputs to the comparator are the bases of the two transistors.
Q4113 serves as a high voltage buffer to switch Q4114. One
input is fed from the error amp and reference block which is
formed by U4103 and the voltage sense resistors R4136,
R4137, R41 I 1, and R4112. The parallel combination allows
the output voltage of the supply to be trimmed to exactly 130
volts. U4103 contains a 1% voltage reference and the error
amplifier. C4103 and R4149 provide the gain compensation
for the error amp to ensure the power supply is stable into any
expected load.
Q4104 provides the time delay which is necessary to keep
the MOSFET on until the current through it has dropped to
zero. The collector is capacitively coupled to the base of
Q4108 to provide a short duration pulse which charges
C4109. C4109, Q4108, R4118 and R4120 form a ramp
generator.

I recently fixed TWO of these sets, doing the same thing as yours. I did NOT use a kit, rather, I replaced the two items that usually go bad. the MOSFET, and the electrolytic cap, which kills the mosfet. Both are still fixed. REPLACE the fet, and the cap, C-4106, a 1/100v... that should do the trick, in 90% or better of the sets, it does!! BTW-- the MOSFET should how pretty high from D to S, and usually whan they fail in that set, they show low(under 200ohms) or so. BTW--an IRF-740 will work for the MOSFET, if you cant get the RCA #.
At least you are not dealing with a ctc-203 , MM-101,or any of the "cold" type switcher--I have to deal with those all of the time. If EVERYTHING is not right in the supply-- BYE-BYE Switching transistor!!

I forgot to mention that R136(R4136) was fried to be open. Andy's schematic helped me get that resistor's value and I put a close one in along with a similar looking little yellow rectangle cap and an SCR from an old Macintosh computer and it works great so far! I didn't have time to verify voltages so I just hope the set lasts for awhile. I have played it for 8 hours and it seems fine so it is now at the home of my lady friend who needed a break.

Thanks again Jack S. and everybody,

John