63 silvertone
 

ok im back again with the same set it is a 63 silvertone ctc12 clone. i have a few issues and to this day i cant seem to solve. on the schematic there is a section of the 6bk4 and it has 2 lines coming together with a circle on each end and this is where to check regulator current but it shows a jumper that goes across it so is this jumper always across these 2 lines and then removed to put a meter in between and then put back or is it left separated. because i removed this jumper and now have no control of the hv 30kv is high, not right. the other problem is like on modern tvs there is a screen control on the flyback and if adjusted to high then there is lines across the screen until its lowered and this is what i have on this silvertone it as though the bias is to high but it is counterclockwise all the way down and these lines are each one is red, green, blue, and no mater what i do adjusting, subbing tubes nothing gets rid of them i am thinking there may be a resistor or a shorted cap in the chroma board , i just dont know at this point. i have since replaced the flyback when i discovered the 1v2 was wired wrong and i had focus issues now i dont just the lines. so i dont know if its a bias issue or a color drive issue. hopefully someone can shed some light on this never ending sega with this set. so what ever is going on here still is affecting the hv if that jumper stays in place when not checking reg current then ok but i then have to have the hv at max to get decent hv and if something is being driven to hard will have an affect on the hv and this is what it seems like thats going on here. the 1.5meg resistors are good and the high watt resistors around the drives as well check good. :scratch2:

You need to replace the jumper, its only removed for testing with a current meter.

The diag lines you see I suspect are due to trying to drive the CRT too brightly.

You need to follow this order

1) set the HV up with a HV meter on the CRT anode and the current meter for checking shunt current on the 6bk4, follow the sams procedure, please don't jump around. This wil include not only the shunt current but the cathode current of the horz out tube, again all of this is in the Sams.

2) setup up the drives using the setup switch and again following the procedure, this will include the correct setting of the bias pot or switch (which ever is used).

3) check the grey scale and adjust the bias pots for no tint in the high lights again part of the setup covered.

My "guess" is you are simply driving the CRT too hard (maybe its getting soft).

If for some reason the 1st 3 steps do not work then you may have a circuit problem that should be addressed. Good HV regulation is a must, trying to get a good pic with out it is a waste of time. You also need a good grey scale setup, if the set can not produce a good BW pic then no need to try for a color until that is resolved.

ok well i have done this except the reg current on the 6bk4 and the bias IS DOWN ALL THE WAY AND THE 3 COLORS RED, GREEN, BLUE drives are completely down, off and still have lots of color and with the b@w pic there is still visible lines but bearly. how else could i be trying to drive the crt to bright i took away all that brightens the crt and still have the lines. this problem has gotten worse each time i would run it for alittle while and now its at the point im trying to get to the bottom of it,lol, its making me crazy. this gave me the idea that something on the chroma board may be bad, i have done so many grey scale setups. the reg current is in milli amp or micro amp or is this the same,lol...

with the G2 drives all the way down and the bias all the way down you should not be able to get the setup lines and the crt should be dark.

You have a problem with the voltages going to the CRT pins. You need to get out the VTVM and start checking the K, G1 and G2, to narrow it down to what is the problem, then you need to see if the pots that control them are indeed working.
but 1st you need to make sure the HV is correct.

If you do not already own it I HIGHLY suggest you get the TAB book vol 1 RCA service manual by Carl Babcoke. He does a great job explaining all aspects of early RCA color sets, and goes into great detail regarding trouble shooting.

yes the crt is dark but still see the drive lines and i already checked the pots and they are in range. when i put the jumper back i will be able to adjust the hv but what is going on it struggles to regulate yet i can get it adjusted to 25kv but with the hv pot maxed. so ill have to check the voltages at the crt and hopefully ill get somewhere there.

Could your control pots be going open, or the supplies driving them be feeding the wrong voltages?

EDIT: Should have refreshed the page before replying.

problem is i dont have any books of sort to give me any guidelines as to what voltages should be at a given place or anything to compare. so im working in the dark,lol,lol.....

you must have the jumper in that's a given.

You should have good HV regulation. If not then you need do the HV setup which includes current checks of the 6bk4 and the 6JE6.

the next step on what to check will be dependent on the outcome of those checks. Stop worrying about the lines until the HV is working correctly.

I am not going to list the possible problems as its just a lot of speculation with out knowing the current in the regulation and horz out tubes. I don't believe in random attempts to solve a problem. there is a methodically approach diagnostics. You MUST have good HV regulation, after that you can move on to the next issue.

the book I referenced is on ebay all the time.

The Sam's should list voltages at important points on the schematic. Once you have your HV right (As Dave said do that first) if the lines persist check that the voltages going to the pins of the CRT are in the correct range, and verify that control adjustments change them in the expected manner.

Ya know..... screwin around like that and letting the hv go up to 30kv is gunna
let out a buncha those little x-rays.... and they gunnaroastyernads.....

just sayin..... be crarful...... mostly cause ya can't see em comin.....

.

ok I am going to go ahead and take a leap of faith here with Timmy and GUESS what we are talking about.

I am currently uploading a video of a set that exhibits what I think Timmy is talking about ( I don't recall seeing any pictures or video). it will be done in a few..
One thing for sure if I reduce the brigthness control I can eliminate them.

IF its what I think it MAY be some kind of vertical retrace issue. Note the issue I see does not seem related to the color lever setting on the front of the set. It does seem related to the brightness and contrast settings. This would point to the luma signal from the video out where the vert retrace pulse is fed for vertical blanking during the retrace interval.

a wild guess could be assuming the level and duration of the pulse is correct, would be maybe an issue with the video out tube (poor gain)? I have no 1st hand experience with this being a cause but I have noticed it before, generally shows up on tube that are not it the best shape, hence I just assumed it was related to the condition of the picture tube. Perhaps a cut off issue. I do know that at least in the CTC-17 there was a transistor inserted into the vert blanking. I have never tried to increase the amplitude or duration of the pulse to see if this was indeed the issue.

Now that I have reversed myself and gone ahead and speculated, I will see if that video is done and will link it here.
I just checked the schematic, the vert blanking pulse is fed in at the plate of the video out (cathode of the CRT) so guess the gain of the vert out tube is not an issue, that leaves either not enough of a pulse or not enough cut off control of the CRT.


Timmy get that HV fixed.

here you go Timmy, don't leave me hangin'

I did notice that on the CTC-35 the vert pulse was fed into the grid of the second video amp (wrong phase for video out grid). Maybe that would be a more effective blanking, assuming its just that a weak CRT could use the help.

new link

https://www.youtube.com/watch?v=39Dl...CVtyRrqXVtll-g

Delete

come on Timmy don't go dark on me.

For some reason I can't make the above link work - takes me to Google sign in page.

This one seems to work(for me).

https://www.youtube.com/watch?v=39Dl...CVtyRrqXVtll-g

thanks for getting that to work. link works for me, but maybe I put it there after logging in? anyway hope Timmy can confirm this as his issue.

if link does not work can just you tube my channel Dave WM

Yeah, that's what had happened... The link you posted was to the 'edit my video' type section within your account, (notice the /edit?o=U part), you must have grabbed the URL from within your account, not the published link.

The best link is just simply:

https://www.youtube.com/watch?v=39DlVjo9hSY

so silly YouTube doesn't try to autoplay the whole list of videos.

this looks interesting a two pulse blanking circuit

http://www.google.com/patents/US3247418

Note the pulse to the G2

yup i also had a problem getting into that link. when i posted what i did i had already pulled the chassis and i was going to go over the components i had put in when i first got the set. my first mistake was the doubler caps as they should both be the same but what i did was for a 250v 160uf i put 2-250v 100uf in paralelle and for all i know one of the 4 caps may have went bad and the voltage is not what it should be, its like batterys in series, one goes bad it pulls everything else down . resistors, and other fixed caps i put in i have to check. like i needed i think it was a .12 630v but moyers gave me a .1 and a .022 to make up this cap and i was told by someone here at karma that the .1 was enough so i had taken the .o22 out but i had more problems then what i had already and i think it was the drive lines issue that i have now. so maybe these caps should not be parralelled as i know some parts of certain circuits this should not be done because this may be a timing circuit . so all in all i didnt have the lines in the beginning but when they appeared they just got worse every time i turned the set on so clearly it could very well be the crap i put in this set and how i did it, paralelling caps, no.no, on my part. temporary may have been acceptable but not permanent. i will get back soon with an update...

So were the lines in the video what you are experiencing?

i am almost certain it was the lines because i had since got tired of the hv issue and even when i had taken the 6bk4 cap of i didnt get hv like i get now since changing the flyback. but yes i was more concerned about the lines and this is why i decided to go ahead and check my own work and fix the screwups or the should not have done crap. i never did get to the link you had sent.

just go to you tube and look up my channel

Dave WM

or just google

CTC-12 retrace

There is nothing wrong with putting capacitors in parallel to duplicate a out of production value. For instance if you need to replace an original .25uF 600V capacitor, you CAN replace it with a .22uF 630V in parallel with a .033uF 630V and it will work fine, not to mention be a more correct replacement, value wise than the .22uF part alone.

Trust me I use parallel caps all the time in my restorations, and they always work just fine.

ok got the video, yes they look like that with each line a different color and if i move the contrast i can make them almost not there. the vert hold if i make it roll there is lines but they are lines with dots on the right side they are somewhat different them the color lines that are there all the time. i thought the retrace lines are the ones that the lines go half way across the screen towards the right and at the right they end with what looks like dots. but just a still pic yes those are the lines im talking about, lol ,lol. so ill have to concentrate on a verticle issue weather cap and or resistors. i tried another vert output tube and was no change so i ruled that out. thanks for that video it was very helpful. oh and by the way the set on this page is the very one with all these issues,lol,lol....

Ok there are 3 parts that are used to cut off retrace.

You need to look at two resistors (100k,68k) and a .01 disk.

You need to check your schematic and find them, they go from the plate/transformer vert lead to the plate of the video out tube.

Its unlikely to be the problem, but its where you should look. I will do a video later showing where they are (one resistor and the cap is on the chroma board, one resistor is on the deflection board).

The more likely problem is just a CRT that is getting soft to the point where the setup bias is just beyond the point of the blanking pulse ability to blank it out (the CRT is blanked by the reg blanking pulse from the video signal AND the blanking pulse from the vert out).

It "may be" possible to overcome a weak CRT (or one with poor cut off) being the issue by the mod noted in the patent. I say "may be" since I am only speculating that the mod noted would generate enough extra cut off voltage to resolve this.

ok interesting info thanks, as for the crt it is original from 63 but tests good with good cutoff but i do hope its not the crt.

if it test good with good cut off then its likely to be one of the following

CRT setup incorrect (kine bias/drive pots)

AGC (too low)

Open resistor or cap per my prior post.

It has to be one of the above so there is no need to start replacing caps (like the .12 you mentioned before).

What is confusing is you said it was fine then you made cap changes, then it get worse each time you turn it on. That is a very odd situation.

This is why I do not recommend mass recapping as a rule, although I am having a hard time trying to figure out how it gets worse with each time you turn it on.

since the lines started it has got worse no better so when this problem started i looked into things to try to find out what may have been causing it. i didnt make any changes just that i pulled the chassis the other day to check caps , resistors, ect. the kine bias pot is 6k and measures good that was the first thing i checked. so then i should leave the.1 cap and the .022 paralled in place for the.12 that the sams says and what i took out.

I don't know the .12 you refer to, but I am pretty sure its not the problem.

I am uploading a video now showing the likely suspects, its 11min long so will take a while, check back in about 1 hr.

the old cap when i first got the set was a .12 600v and i put in place a .022 and .1 600v together in parallel. was not sure if this was a good idea from the start.

if the .12 was bad, then its ok, if it was not bad then its still ok, just not needed. Recapping as a way to fix problems is not a good idea. You may get lucky but you learn nothing. Better to learn how things work the diagnose the problem, esp with sets of this era, the caps are often fine, and recapping just introduces the possibillity of errors (wrong values broken traces etc..)

Besides what do you do after recapping and you still have a problem, or if it works for a year then a new problem, recap all again? so learning how things work is the way to go and what I think this forum can help you with.

Ok new video is up see part 2 regarding the parts that can be checked.

I think I would have just popped a common .1mfd. 600V in there to replace a .12 which is oddball. The general rule is to always go higher, not lower in both capacitance and rated voltage value, but the difference between these two would not be significant enough to warrant two caps. And I do believe that the capacitance adds when two are paralleled, but the voltage rating is compromised. I forget the calculation on that and may have it backwards. I hope one of the other members will elaborate on this and correct me if i'm wrong on the .1 idea.

great video and i found the cap and resistors as far as the disc i will have to change it because i have no way to positively check it and what is the voltage on that .01 disc cap? the resistors on the other hand well the 68k was found to be 69.8k and the 100k was found to be 100.8k both of which is well within range. so now if i can find out what the voltage rating is for the .01 disc ill change that just to be sure . the doubler caps being i have 4 in paralle 3 of which are the same brand but the 4th one is smaller and a different brand so i have 2 caps rated 450v 470uf i was going to put in place of what i have now and while it is a bit overkill at least they are both the same and there will only be 2 of them, just to rule out any possible problem with the ones in there now. im still debating weather or not i should leave the 2 caps in paralle that are .022 and .1 for the .12 that was in the set originally there are certain opinions about doing this with caps because one could go bad and pull down the circuit that its tied to so i would figure this could do away with any possible future problems since i dont have a cap tester on hand.

I would say anything rated more than 100v on the .01 should be fine. That being said its very UN likely to be the problem. Disc caps are very reliable.

I did some more checking on my set, the one in the video with the problem. . The CRT would not produce any lines in setup mode unless i advanced the red gun fully CW and then advanced the bias pot about 1/4 of the way. I tested the CRT with my CR-70 and it tested quite weak (well into the red zone) with very little cut off response.

So with that I presume my issue is a weak CRT (its not very bright either).

I suggest you try checking your CRT again, and if confirm that the CRT tester is working properly.

IF your CRT is good with a known good CRT tester, you should also consider checking the filament voltage at the CRT just to make sure the filaments are getting the correct voltage from the set. Again this is a long shot.

remember CRT testers are not infallible, just cause it says its good does not mean it is. The only way to be sure would be to check the calibration of the tester OR test it on a known weak CRT to confirm its function.

Before messing with the power supply caps you should just check the B+ voltage to see if its what it should be with a multimeter. I doubt a B+ fault would be causing the issue.

well i do have another set round screen with a very weak red gun the others are not that great either however i also have 2 more crt testers and get the same from the weak crt. and the set with the weak crt has a perfect picture and clear no lines, even though i have video issues with that one it still has a good pic. so with these testers i will go ahead and check this crt and the cutoff again but if it should show good cutoff i dont know where i will go from there. it certainly to me sounds like you know a whole lot more about these sets then i will ever know. on my bk440 which i have 2 of them and one is recapped and the cutoff the last time i checked on both showed the same and where it has the line on the right and left the test on all the guns were less then half on that scale but not at the quarter line but rather higher then the quarter itself.

I suspect that the designer chose .12 over .1 for a good reason... I would leave the parallel substitute as is (if they check good).

A little refresher on series & parallel capacitors:
http://www.coilgun.info/theorycapaci...apacitors2.htm

jr

well i could take the 6dq5 out and run the chassis to check b+ but it may show ok but would it possibly show less under a load if there is a problem within the caps.

regarding the .01 ceramic disc cap could this cap be subbed with a .01uf metalized film capacitor ?