Checking Vertical Output Transformers??

[Tube TV]

I have a schematic for the space command remote chassis .
Does yours have 3 6AU6s and 1 6AL5 1 6CM7 ? If so Ive got the info for it.
these were in canadian models in 1958-59
I would say it would be safe if you pulled the horizontal output the flyback will be protected and there would be no high voltage .
the hum , what cycle is it ? is it 60 cycle or is it different ?
that's good that your set has the same vertical circuit as my schematics
it's probably the same circuit . you might be right about the remote chassis
causing problems and I have the info for the chassis plug and the socket wiring into the tv chassis .
Does you socket have 8 pins all around then the 9th is more towards the center ?

I can get you copies of this if it's the one that fits your set .


Any susgestions or comments please , if disconnecting the horizontal output tube would be allright ?

[Tubejunke]

My remote chassis uses 3-6AU6, 2-6CM7, 2-6AL5, and 1-5Y3GT. The power connection is a 3 wire rectangular plug that inserts beside the main power transformer, also there is a 5 wire round socket for the wires from the tuner motor.

I think it would be safe to call the hum a 60 cycle. It is similar to what you hear when you have bad caps in a power supply. Actually I didnt know that there were different kinds of hum. I started in working on old radios and I have heard many a radio with a similar hum.

What method do you use for measuring voltages when a chassis must be separated from other components? Maybe I know the answer to my question. You could use jumper wires or extentions and a test crt in order to have the chassis doing what it is supposed to do on the bench. In my situation again the crt, the tuner, and remote chassis are out of circuit when the main chassis is removed.

[Tube TV]

Tubejunke , I got that schematic too, the rectangular pin has , black , gray , blue wires on it ,it should be blue they are coded as BL im assuming they are blue . Two of these go to a power trans then the 5Y3 , that operates the remote system . there appears to be a 5 pin plug for the motor however I can only find 4 wires , the 5th center terminal has no connection . there is also 1 selenium rectifier in the power supply . does yours have that ?
Would you like a copy of these schematics ?
When I have measured voltages in the past I have had the tube out , some sets you can flip the chassis and connect it to the picture tube . but this might be easier said than done , alot of the TV's I have are not bigger than
17 "
How would it be to remove the controls and the CRT ? your best bet is the extentions like you said earlier .

Like I say , I have the schematics , If you want them send me a PM with your address and I will get you a photocopy of them .
I would scan them but I still havent got a scanner yet .

murray

[Eric H]

TJ, did you change all the can type capacitors or just the one for the power supply? (usually C1)

One of the cans is connected to the vertical and will kill it if it's bad.

I just got done with a Zenith Flash Matic and it was a bit of a pain, I had to remove the tuner and remote chassis and hook them up on the bench.
It wasn't as bad as it sounds, my tuner just had two screws holding it in the back and a slotted bracket up front, popped it right out and hooked it up.

A test CRT like this one is a big big help:
http://cgi.ebay.com/Vintage-NOS-GE-G...QQcmdZViewItem

Same thing but in a box: http://cgi.ebay.com/Tele-Check-Model...QQcmdZViewItem

It gives you a place to hook the second anode up and you can see what the set is doing while you work.

[Tubejunke]

Hi Eric, yes I changed all of the multi-section cans on mu chassis. As for the test crt I have known that they were once available when shops still repaired what we now consider "vintage". Thanks for the link. For those of us who do not have one and want to check some voltages a couple of us are wondering what the right way would be to aproach doing this on a chassis that has been separated from the crt and tuner. I know jumper wires are one way. However it would be a pain to extend the yoke wires to a remote location.

Obviously you wouldnt want 2nd anode voltage flopping arond loke a Cobra snake. I have heard to remove the horizontal oscillator tube to disable HV and avoid some kind of damage to the flyback. Does everything have to be hooked up to check power supply, sound, and vertical circuit voltages?

To my friend Murray I am sending you a PM and for the thread no my set does not have any selenium rectifiers. Transformer and tube all the way here..

[Tube TV]

Tubejunke, I got your PM this evening , I will mail the remote chassis schematics the next time im in town .
probably in a few days .

Murray.

[Tubejunke]

Thanks a mill Murray!!!

[Tube TV]

The original diode sounds good . Im not sure if you already know a easy way to test diodes , but this is how I do it . a analog meter is easier for this .
Touch one lead onto the anode and the other one on the cathode .
depeding on the polarity it will read about 2 k or if it is in the other position it will read anywhere from 40 K to 100k .
for example , you touch the test leads on the diode , it read 2K
you reverse the leads red lead where the black was , if it then reads 40K the diode is allright .
If it was defective it would read for example 2k and when it is reversed 2K .
The other thing that happens is the when it is open it will read 100k or more either polarity .
then there is the shorted diode where either polarity reads 0 ohms or 100 ohms .
the main thing you want to look for is this ohms variance between the polarities , this indicates that the diode is allowing current to pass in only one direction .

Im glad to hear that your Zenith has the same schematics . I got the scanner last week I could send you the alignment info for it once you get it running .
I looked the # of the diode that you bought in my ECG cross referance , I have no listing on it , I am surpised that it was not in there .
A rectifier diode out of a old transistor tabe radio or other small Item should have one that will work .
It seems to be for the bias for some of the tubes " 19 volts 12k ,22k 26volts"
note on the resistor next to C17 , just ahead of the diode . it dosnt seem to handle any great current
what was the schematic # on bipolar capacitor you changed ?
Then I will know where it is in the circuit .

Tubejunke , Is this like your chassis layout?

[Tubejunke]

Tonight I used a better meter and got some odd results. The old diode measures 10 meg ohm one direction and about 5 or 6 meg the other direction. The real weird thing is the old diode seems to have a capacitor like effect on the meter, only backwards. The scale actually counts down if you hold the leads on it for a minute.

The new diode measures a rock solid 250K one way and infinity the other. I smell trouble with those high and erratic readings with that old diode. I have always heard that a rectifier diode should pass virtually no current one direction. My readings are far from that.

As far as my new diode being correct the package mentions that the diode replaces ECG116, GE-504A, And SK3313.

The non polarized cap I mentioned looks like it says C25. Getting the c25 was probably dumb as far as WHERE it is on the schematic. I mean it is across two relays and eventually goes into the motor socket. Obviously something to do with the channel select signal process. I bought it mainly because I wanted to replace all of the electrolytics and that diode on hope that something might come of it. There are only 3 or so other electrolytics that I already have in stock.

[Tube TV]

That reading sounds funny to me also , the replacement diode is good for 1 amp of forward current max . It will work fine in there , the old one might be feeding AC into the bias section causing the 60 cycle hum and also weakening the vertical oscillator causing the output to be less . I would say change it , you have nothing to loose on it .
let me know how it goes .

Tubejunke , Does that look like your tube list and chassis layout in my previous post ?

[Tubejunke]

I'll try it out this weekend. Your last statement is exactly what I was thinking. I just have a rudimentary knowledge of electronics. So I wasnt sure if I would have been making a stupid statement. I understand a whole lot but I have a long ways to go. Thats why this site is do great. I can ask for advice and sometimes give advice.

What we are doing with vintage equipment is not taught in school anymore. Most young techs with a degree and a fat wallet would look at you like you were crazy if you slapped an old 50's tv on his bench and said fix it...Its great we can keep this knowlege alive.

And yes, the last tube layout is what I have...

Thanks
Tube

[Tube TV]

I have the same problem here the last tech retired last year , and he was not interested in tubes that much , I always get told , " why do you want to fix that , its B&W and it old ?" All I tell them is , " Thats the whole point or my collection " .
Audiokarma is a great place , I really enjoy discussing old tv's and doing what I can to help out a fellow collector .
I ran into a previous thread from 2004 , since then have you changed the electolytics ? and the 5U4 ?
If you want to leave the cans , there is a great unit for testing them .
A Heathkit capacitor checker ,the C-3 is a great unit and will test for leakage using a voltage source it suppies to the cap at the proper working voltage .then it determines if the cap is leaking or not ,plus it has a resistor checker in it also , it uses a magic eye . They sell for 35 buck usually .
It would pick out problem parts in a hurry .
I have the sencore LC2 leakage checker and I dont know how I lived without it .
It's the best $ 28.00 I ever spent .
I will go throught the schematics that I have and see what I can find that is perhaps powering the vertical , and also the sound circuit .
Good luck with the diode .

[Tubejunke]

Yes I changed all of the elecrolytics. When I brought it home and heard the hum and saw the lack of vertical sweep I knew (thought) it was time for a simple cap renew. Now here I am a few years later with the same symptoms.

I changed the bad diode tonight. No change. I really had some faith built up in this and STILL nothing. I just dont get it. Actually the oscillator sounds like it is running at a more normal speed and I have maybe 3" of height. Still no signal at all. I've checked and or changed all of the tubes. This one is for a pro I guess. If the set were of the type that the chassis and crt pulled out together I could at least do some voltage checks. This set is in pieces every time I yank the chassis.

Too bad there are not many pro's left. If so I would just take it to a shop and say FIX IT. Someone who is set up to do this and has the knowledge would likely figure this out in no time at all.

I hate this failure because the set is in like new condition and its a waste to have it sit around useless or worse a shame to scrap.

I would love to have one of those capacitor test units. I have a couple of DVOM's that have a capacity setting but there is no load applied, which is the key to a proper test.

[Tube TV]

Tubejunke , try this , just to see if the vertical oscillator is running , once you have the set on , turn the vertical hold control and listen to the vertical output transformer you will hear that typical buzzing sound ( pull the wire off the speaker if nessisary ) turn the vert hold , the buzzing sound should change in speed , slower or faster it is normaly locked in by the sync at 60 cycle produced by the oscillator , The vertical oscillator creates a sawtooth pattern , but a sine wave will drive the vertical output . there could be a signal comming off the power supply that is interfering with the vertical osc but still creating some raster because the line current is 120 V 60 cycle .
If the sound from the vertical oscilator varies than this would indicate that it is oscillating , if not that is would mean that there is a loss of voltage in the power supply or a loss of a bias volage in the oscillator perhaps .

[Tubejunke]

I have been taking note of the presence of the sound of the transformer. Earlier on in all this I remember the hearing the sound but it sounded oddly slow. Now the sound is much faster. It sounds like any of my other working sets. I just can't get the sweep, or not much anyway.

One thing that I noticed is that what height I can get seems to go from the center of the crt up, if that makes sense. I can tweak the vert lin. and vert. height controls and I notice that only one of them effects the sweep. What it seems to do is raise the height from a collapsed line up, never down. I always thought that the lin. and height controled separately the upper and lower portions of the raster.

I guess my next step will be pulling the chassis again and doing a piece by piece check on resistors. I have done this once before but perhaps I missed something. Of course I have tried different tubes in the vert, sound, and tuner sections.

Thanks for sticking with me on this. I guess the subject is getting boring by now. Maybe I'll have good news one day.

Do you think you could find a Thordarson or Merit yoke cross reference for me? I have a supply of NOS Flybacks and Yokes. If I had this one in stock I could pop it in just to see if the yoke is the sweep problem and the lack of signal and hum is a whole different problem.