Ctc-16
 

thought I would start a new thread now that I know the chassis I have.

this is my 1st early color. when I got it I started a slow power up on a variac (metered). when I saw 1 amp at 10v I knew there was a problem so stopped there.

I disconnected the B+ from the bridge rectifier, powered up again, no problem think it was about .7 amp IIRC all filaments (not the crt the chassis is out on the bench at this point). came up.

B+ was about 400v disconnected. The resistance at the 1st 80uf cap was 24 ohms :no:

I started with the easy stuff the filter caps were in pretty good shape (tested with a cap tester for capacity and leakage at rated voltage).

moving a long I started unwrappping various B+ feeds to thinking maybe a shorted bypass (not likely since mostly dipped caps, only a couple of the HV ceramic tube types and the were ok).

last thing I check (prob wishfull thinking it was not the problem) was a transformer behind the HV cage. I assume it is a vert output, but it also drives the convergence board. Being new to color I am just guessing about this.

anyway it has 5 primary and 6 secondary winding. Two of the primary windings are green and green with yellow strip. the GY connects to the 400v B+, I also disconnected the other G on the primary. doing this removed the 24 ohm reading and now I get 8k

At 1st I thought I had a short in the transformer from the primary to the secondary (there is a lead on the secondary that goes to ground).

but I still need to trace the remaing 3 primary leads (blue/red/yellow) to make sure they are not the problem. I hope to pic up a RCA service folder today to aid it the tracing.

primary side blue and red seem ok, the yellow which goes to the yoke has 2 ohms to ground. I am going to have to stop and go get the service manual, just not sure what the internal wiring of the tranny is...

Which CTC-16 do you have? The earlier style or a CTC-16Xx chassis? I'm not sure offhand what all the differences are, but I know there's different Howard Sams for 'em.

Oops, nevermind my chassis question..I noticed your other post. I have a CTC-16 E that I've had since the seventies that still works but I need to refurbish the electronics and deal with a few quirks.

I like the fact that the later versions (like yours) came with the RCA "Hi-Lite" CRT which is an awesome picture tube when in good condition.

got the schematic, not looking good on the vert output. the primary is green,green white,yellow. with all those out of the circuit I still have a low resistance reading to the chassis.

Moyers had it so its on the way :banana:

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getting ahead of myself, but I would like to make a simple box cabinet with some nice thin legs for it. The old cab is shot.

reading the service manual it says about setting the tuner in the service position, I cant seem to figure out how to bolt the tuner or in some other way to place it on the chassis to make working on it easier. I am guessing there is some way to attach it to the chassis to reduce the awkwardness of the two parts.

Yeah, there are a couple of screws/small bolts near the AC line plug line in. The tuner will fit right into those screws.... knobs facing upwards... and then you tighten the screws. You can leave it there and do all you need to the chassis out of the cabinet.

got it thanks Charlie!

while waiting for the vert out xformer I went ahead and repalced a singe 50uf 150v cap (tested leaky). I am going to give the big can caps a chance to reform I just want to make sure it works and the CRT is ok before going thru the effort to stuff them, They are not shorted, I will monitor the current and see if they come up on the variac when I get the B+ worked out.

Tuner issues, the UHF can be tuned by turning the dial indicator no problem, but not with the tuning knob. If you push down you can fine tune the VHF, but when not pushed down it engages thru a series of gear to the UHF.

It seem that the alum gear is seized to the shaft. What I dont get is how come the UHF can still turn with that alum gear seized? My guess is there is just a friction coupling that normally works when the alum gear is not seized up. It also looks to have some kind of built in gear lash control.

I looks like I may have to remove the lashed gears on the tuner in order to get access to the screws that hold the alum gear assy to the tuner box. then I can work on getting that stuck gear off and re lubed.

Dave,

What are your tuner numbers? KRK... Is there a TMA number on the tuner cluster? I have an RCA guide on almost all of the RCA 60's and 70's tuner assemblies with breakdown of the mechanicals. I can get a copy of the UHF area for you if I have the above info.

Lots of questions, I know - and one last one? Where are you located? Most of us have our location listed in our profile - helps with the local help...

Cheers,

TMA 96A

updated profile.

Got a hickok 533 tube tester today to play with looking for a manual.

.....and me just back from Lake Buena Vista!!


I'll look tomorrow for the TMA info.

Check the Boatanchor Manual archive (BAMA) or it's mirror for the 533 manual and tube data. 532, 533, 534 and 600 all share the same tube setup manual.

Cheers,