View Full Version : Need a Kent 630TS schematic


miniman82
08-06-2017, 04:21 PM
I'm man enough to admit when I'm licked, so here goes. Been working on this clone for a while now, but still can't figure out the horizontal circuit. Most of it seems to follow the original 630 schematic till you get to the damper and flyback, then all hell breaks loose. The fly is not what you normally find in a 630 chassis, it's been swapped out for something else so it could drive a 21" picture tube. The number on the fly is 235T1, which still seems to be an RCA part number but it's a fly for a wider deflection angle and also higher anode voltage set.

How it's wired makes absolutely no sense, so I'm stuck without a schematic. I mean there's wires from the fly that tie into the 6W4 damper heater (WTF?), capacitively coupled horizontal deflection but then there's no means of centering the picture since there doesn't seem to be a centering pot, the thing is a real rubix cube.


Right now I have the correct drive waveform going to the 6CD6 grid, around 120v P-P, the grid bias seems close to what it should be (cathode is 40v over the grid), but I can't get more than 1.2kv out of it no matter what I do. Post recap I did have to futz with the value of a timing cap on the horizontal oscillator to get the required 15,750hz, but other than that it would appear things are doing what they are supposed to do- aside from the fact that there's next to no anode voltage.

Only thing I can figure is either the fly is toast or something is miswired somewhere.

So if you've seen a schematic for a 630 chassis using a non-standard flyback shoot it my way. Otherwise my color wheel set will go on the back burner till I can figure this thing out.

tom.j.fla
08-06-2017, 05:05 PM
It would be nice to know the model number, that said check RIDERS' volume 13 for KENT model 2430. Saw 2 about 40 to 45 years ago. All the best, Tom.J

miniman82
08-06-2017, 05:37 PM
I would love to provide a model number, but the ID plate seems to be missing. The only thing I have is a tag on the chassis that says 'Kent Custom Craft', and the fact that it's 630 based.

tom.j.fla
08-06-2017, 07:09 PM
Well ok,from your description of horiz. output it sounds like KENT chassis 630d19,630s19,1930,1930d or 2430 found RIDERS book 13, check there & see if it makes sense to you. Tom.J

miniman82
08-06-2017, 08:13 PM
I can't seem to find anywhere to download riders tv13, is there a link to a scan?

tom.j.fla
08-06-2017, 08:18 PM
Sadly no you have to buy it from www.ke3gk.com the 27 volume set is about $60.00. Update you will find the rider's manuals at ke3gk manual depot on the bay. All the best,Tom.J

Tom9589
08-06-2017, 08:54 PM
The flyback might be connected to the damper heater so that the potential difference between the heater and the cathode is reduced, similar to the way CRT filaments are often connected to the cathode to eliminate the problems associated with heater-to-cathode shorts in the CRT.

miniman82
08-06-2017, 09:10 PM
Usually it's done with B+boost bias though not with a pulse from the flyback, I've just never seen it done this way before. A schematic would clear up the confusion for me, hopefully Crist has what I need (said he may have a scan).

Crist Rigott
08-06-2017, 09:38 PM
The info is on its way! Good luck.

miniman82
08-09-2017, 09:52 PM
Schematic from Crist gave me some additional clues, but it's not exact to what I have in front of me. Model number is 2464, if that helps. I found a faded paper tag with that on it, I hope that's what it is.

madRad45
08-10-2017, 11:49 AM
Check out page 79, Figure 1, of the October 1953 Photofact Servicer. It shows the schematic of an RCA 235T1 being used to drive larger screen tubes. The text for the figure is on the top left of page 78. Here's the link:

http://www.americanradiohistory.com/Archive-Service-Magazine/50s/Service-1953-10.pdf

miniman82
08-10-2017, 10:04 PM
That might just be it, let me compare when I get some time this weekend. Thanks!