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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 07, 2019 4:16 am 
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Joined: Sep Mon 28, 2009 1:53 am
Posts: 327
Location: Bloomington, IN, 47401
aj2x wrote:
I can send you the pages, but since they'd total more than 8 Megabytes it'd take several emails to do. PM me if you're interested.


Got them! I'm going to forward a copy to BAMA for their archives. Looks like all the info I need to get the set restored!


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 07, 2019 4:51 am 
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Joined: Sep Mon 28, 2009 1:53 am
Posts: 327
Location: Bloomington, IN, 47401
I never had a manual for the B&K Precision CRT Tester Model 400 that I got. The closet I could come to was one for the Model 440. Well, I'm reading through it (only 15 pages) and I get to a section titled "Restoring Open Elements". Now, both the Westinghouse and GE showed an OPEN G1, so this obviously had my interest! The manual said to go back a section titled "Restoring Emission" and to try that first.

Believing the GE picture tube to be truly dead, I tried that one first. I was instructed to resolder the tube pins, so I did that. I then hooked up the CRT Tester, set it to "Continuity", and it showed a OPEN G1. Pressed the Emission button and got nothing. The next step was to set the Tester to "Dynamic Intensifier - LO", wait 15 seconds, press the Dynamic Intensifier button for a moment (less than 1 second). I switched back to "Continuity", and to my utter amazement, it now displayed as "GOOD"!

I switched to "Emission" and pressed the Emission button, but got nothing on the dial. I tried "DYN-LO" again and still nothing. So, the next step was to move up to "Dynamic Intensifier - MED", wait 15 seconds, press the "Dynamic Intensifier" button, then recheck both Continuity and Emission. Continuity was still good, and now Emission was in the green zone, up around 400! The tube might be back from the dead!

I did the same with the Westinghouse picture tube, and fixed its OPEN G1 after the first use of the "DYN-LO" setting. However, Emission was only about 200. I repeated the "DYN-LO", and got emission up to about 275. I decided to try "DYN-MED", and emission is now above 500!! WOO-HOO!!

I was excited about that, so I reinstalled the CRT into the GE chassis/cabinet. Did a slow startup, but, unfortunately, didn't get anything on the CRT. The high-pitched whine wasn't as bad (it went almost fully away when adjusting one of the controls on the back for Vert/Horiz stabilization (the knobs aren't labeled; I'll have to remedy that).

I mentioned previously about a bright glow from the HV rectifier tube, along with small arcing between a metal band attached to the yoke and the glass of the CRT itself. Tried to capture a photo of the arcing but could never get it.

Any thoughts about the rectifier glow (see image below)? Is the tube bad, and that's what's causing the arcing? The glow doesn't seem normal to me, but the arcing suggests to me that the flyback is good - good enough to create an HV spark!

Of course, since I haven't touched any other components on the GE chassis, it might be bad caps, open resistors, etc., and these are causing the glow and arcing. I won't know for sure until I recap and check for bad resistors.

Image


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 07, 2019 4:40 pm 
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Location: Pewaukee, WI
Either you HV rect or CRT is defectively gassy. Try a different HV rect and see if that fixes things.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 07, 2019 4:45 pm 
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Joined: Sep Mon 28, 2009 1:53 am
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Location: Bloomington, IN, 47401
Electronic Memory wrote:
Either you HV rect or CRT is defectively gassy. Try a different HV rect and see if that fixes things.


I'll give it a try. May be awhile before I get to it. Waiting on caps so I can finish the GE chassis first.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Fri 08, 2019 11:34 am 
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That HV rectifier is definitely bad, it should not glow purple at all. I bet if you touch it (off of course) it's getting hot also.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Tue 12, 2019 3:32 am 
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the dynamic intensifier is used to rejuvenate a crt. this was a stop gap to get the set working till the shop could order a new crt for the customer. i dont think there is any way to tell how long this fix will last. the problem is that sometimes doing this can permanently kill the crt. a safer way is to connect the crt to the tester and let it cook for several hours at slightly incresed filament voltage. sometimes this will bring it back. also a weak crt can be used with a brightener to get a bit more life out of it.

a tube with a purple glow is an indication of a gassy tube. if the tube is bad enough you should see a whitish color in the glass envelope. this means the tube went to air.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Mon 18, 2019 4:39 am 
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Joined: Sep Mon 28, 2009 1:53 am
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Location: Bloomington, IN, 47401
Update: got the replacement caps in, but I've developed a weird tendonitis in my wrist, and it HURTS! I take ****** for my back, and it does nothing for the wrist pain. So, going to have to wait for that to heal before I start in with installing the new caps. I did get a cap over the exposed part of the yoke that had crumbled away. A small piece of 3" PVC pipe, and a pipe cap with the center drilled out.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Mon 25, 2019 3:38 am 
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Joined: May Sun 07, 2017 11:35 am
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Location: Belrose, NSW, Australia
What's the spring around the (bulb of) tube for?

It's for grounding the aquadag - that's the graphite paint. In conjunction with the aluminizing inside the glass bulb it forms a capacitor to smooth the HV.

Re the dollar note, a collector friend of mine recently found over $1000 face value worth of old $AU notes inside a radio find from a deceased estate.
He tried contacting the seller with the aim of returning the stash. Guy wouldn't return his calls - probably assumed he wanted his money back for that old radio!

Better still for my friend, the notes are early issue and now worth at least double their face value!

The sort of thing collectors dream of, and in this case he's a single dad and absolutely deserves some good luck.

_________________
Wax, paper, bitumen, cotton, high voltages - what could possibly go wrong?


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Wed 27, 2019 3:43 pm 
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Joined: Sep Mon 28, 2009 1:53 am
Posts: 327
Location: Bloomington, IN, 47401
irob2345 wrote:
What's the spring around the (bulb of) tube for?

It's for grounding the aquadag - that's the graphite paint. In conjunction with the aluminizing inside the glass bulb it forms a capacitor to smooth the HV.


Good to know! Thanks for clearing that up.

So, I recapped all the old wax caps underneath, and put in new HV electrolytics to replace the multi-segment cans. Tried a slow startup and got nothing. Not even filament glow. Will have fun trying to track down the wrong solder point!

On top of that, yesterday a Windows 10 security update screwed up and deleted most of the files on my laptop. Everything in the Documents, Music, and Video folders. All my docs about the vintage radios. I have a recovery program running at the moment (I'm using an older laptop to write this), and hopefully will be able to recover most of the files.

If it ain't one thing, it's another....

HAVE A GREAT THANKSGIVING, EVERYONE!


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 28, 2019 12:42 pm 
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Joined: Jun Thu 25, 2015 3:21 am
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forget the new caps for now. before doing anything else you need to get the filament string working. nothing will work if the filaments arent lit. once you get the filament string working do a controlled power up and see where you stand.

if all the tubes begin with a 6 or 12 you have a filament string wired in parallel. if the tube numbers start with any other number than 6 or 12 you have a series wired filament string. the 5u4 is an exception to the above. another way to tell is if the set has a low voltage transformer it is a parallel wired filament string. if your filament string is wired in series just like the antique christmas tree lights if one burns out none of them will light. check all the tubes in a tube tester to see which one is dead.

also make sure you change the high voltage rectifier tube. a purple glow inside the tube means it is gassy.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 28, 2019 6:02 pm 
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Joined: Sep Mon 28, 2009 1:53 am
Posts: 327
Location: Bloomington, IN, 47401
thomas13202 wrote:
forget the new caps for now. before doing anything else you need to get the filament string working. nothing will work if the filaments arent lit. once you get the filament string working do a controlled power up and see where you stand.

if all the tubes begin with a 6 or 12 you have a filament string wired in parallel. if the tube numbers start with any other number than 6 or 12 you have a series wired filament string. the 5u4 is an exception to the above. another way to tell is if the set has a low voltage transformer it is a parallel wired filament string. if your filament string is wired in series just like the antique christmas tree lights if one burns out none of them will light. check all the tubes in a tube tester to see which one is dead.

also make sure you change the high voltage rectifier tube. a purple glow inside the tube means it is gassy.



Thanks for the tip. I'll get to it when I can.

A Windows 10 update malfunctioned and ended up deleting everything from my Documents, Music, Video, and Pictures folders. I was able to recover a lot of it via a 3rd-party recovery program, but the program didn't recover the filenames along with the files. So, I now have 200K+ files to go through. Many seem to come from my Internet cache, so you might want to get into the habit of clearing that weekly. The 20K songs I had in the Music folder were backed up on another drive, so that's good.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 28, 2019 7:09 pm 
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Joined: Jun Thu 25, 2015 3:21 am
Posts: 1352
good luck with the computer problem. other than browsing the web watching movies chatting on skype or facebook and sticking in a usb key to get data off it i really dont know anything about computers so i cant be of help there.i do know windows 10 spying and forced updates suck and i wont use it. i will ask my friend to check my internet cash. thankyou for the tip. while i dont have saved music i do have electronic copies of books for electronics that i wouldnt want to loose. i also have a complete set of riders tv manuals on usb. i wish i could get the complete set of books for that but cant find it and the volumes i do find are priced outside of my price range. my camera is a brownie hawkeye so any pics i take i have prints for them not computer files.

one thing when changing condensers dont just change all of them without taking precautions. first unsolder one side of the condenser and remove that end then connect that side of the new one then unsolder the other side remove that end and solder in the new one. do a controled power up every two or three condensers and if things got worse you know you made a mistake. it is easier to troubleshoot two or three condensers than a whole tv full of condensers.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 28, 2019 7:17 pm 
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Joined: Sep Mon 28, 2009 1:53 am
Posts: 327
Location: Bloomington, IN, 47401
thomas13202 wrote:
one thing when changing condensers dont just change all of them without taking precautions. first unsolder one side of the condenser and remove that end then connect that side of the new one then unsolder the other side remove that end and solder in the new one. do a controled power up every two or three condensers and if things got worse you know you made a mistake. it is easier to troubleshoot two or three condensers than a whole tv full of condensers.


Too late! Thought about that very process after it wouldn't power up.

Live and learn.

Larger hard drives just mean we'll lose that much more when the drive crashes. I have 2,600+ movies on a portable HD. Took a LOT of time to rip those to my HD from DVD. Fortunately, every time I go visit my best friend, I take the drive with me and back it up on his system. The odds of both drives crashing and being unrecoverable is pretty small.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Nov Thu 28, 2019 9:22 pm 
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Joined: Jun Thu 25, 2015 3:21 am
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this is a computer we are talking about there. the odds of it working right is a miracle. at least mine allways acts up.

we learn from our mistakes. in this case changing condensers didnt cause the filaments not to light so once that is fixed everything may be ok with the condensers. keep a good thought.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Dec Mon 02, 2019 4:00 am 
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Joined: Sep Mon 28, 2009 1:53 am
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Location: Bloomington, IN, 47401
Okay, so I'm checking the filament string (serial wiring). I follow the procedure in the SAMS, and things are mostly okay. However, I get to a 5AN8 tube and things aren't right. Underneath, I can follow the path as laid out in the schematic. At the 5AN8, I get no continuity on the pins. I pull it out and test it with my Dyna-Jet 606 and it tests at 100! I put it back in the socket and there's no continuity.

The set did have a picture before I began to work on it, and the tubes test okay.

Any ideas?


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Dec Mon 02, 2019 4:04 am 
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Joined: Sep Mon 28, 2009 1:53 am
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Location: Bloomington, IN, 47401
Also, I replaced the rectifer in the GE portable. No more blue glow, but no picture.

I think that one might have a bad CRT, regardless of what my CRT tester says.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Dec Mon 02, 2019 5:49 am 
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Location: Ann Arbor, MI
David Child wrote:
Okay, so I'm checking the filament string (serial wiring). I follow the procedure in the SAMS, and things are mostly okay. However, I get to a 5AN8 tube and things aren't right. Underneath, I can follow the path as laid out in the schematic. At the 5AN8, I get no continuity on the pins. I pull it out and test it with my Dyna-Jet 606 and it tests at 100! I put it back in the socket and there's no continuity.

The set did have a picture before I began to work on it, and the tubes test okay.

Any ideas?

Are you checking for continuity with a meter switched to the continuity position? If so, pull the tube and test for continuity at the tube pins. If that fails switch to a low ohms scale and measure the resistance. If one way or the other you get a reading measuring the tube directly, put the tube back in the set and measure there. If that measures bad, you have a tube socket that is not making connection with the tube. Depending on the type of socket, you may be able to bend the contacts in the socket to make it grip the tube pins better.

_________________
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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Dec Mon 02, 2019 7:18 pm 
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Joined: Sep Mon 28, 2009 1:53 am
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Location: Bloomington, IN, 47401
Tom Schulz wrote:
Are you checking for continuity with a meter switched to the continuity position?


Yes.

Quote:
If so, pull the tube and test for continuity at the tube pins.


Did that. There's continuity at the tube pins. And again, I get filament glow and the tube tests good on my B*K Dyna-Jet 606.

Quote:
If that fails switch to a low ohms scale and measure the resistance. If one way or the other you get a reading measuring the tube directly, put the tube back in the set and measure there. If that measures bad, you have a tube socket that is not making connection with the tube. Depending on the type of socket, you may be able to bend the contacts in the socket to make it grip the tube pins better.


Okay, so I'm an idiot. I got the order of the row of tubes switched; tubes 5AN8 and 7AU7 happen to have the same number of pins, so they fit in each others' socket. Have now placed tubes in proper sockets and relabeled items correctly.

Checked continuity, and it's good for all tubes on the board. Will report on the slow startup later.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Dec Mon 02, 2019 8:32 pm 
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Location: Bloomington, IN, 47401
So, 1st slow start had mixed results. All board tubes have filament voltage, nothing exploded (always a bonus) but no filament voltage to the 2 tuner tubes or CRT. Those are #3, 2 and 1, the last in the chain, so I need to check between tube #4 and tube #3.

Will report later.


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 Post subject: Re: Westinghouse H892T17 B&W TV Restoration
PostPosted: Dec Tue 03, 2019 1:21 am 
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the way a series tube string is wired one end of the line cord goes to the first tube in the string. the other end of the line cord is soldered to the chassis. the circuit is completed through the filament wiring and the filament of the first tube and the wire to the scecond tube then the filament of the second tube and the wire to the third tube and so on till it reaches the last tube filament pin. the other side of the filament to the last tube in the string is wired to the chassis. if there is no voltaqge at the filament pins of any tube none will light. if one lights they all light and they all have voltage. some tubes have a dim glow and are hard to see if they are lit. with tube numbers like 7au7 and 5an8 that tv has a series string filament.

assuming that your crt tester is functioning correctly if the crt tester says the crt has good emitions then it will work given all voltages to the crt are correct. what exactly did you get on the crt when you powered the set on? was there any sound? a no sound no raster problem points to low or no b plus voltage. if you got sound but no light on the crt that would be a problem in the high voltage or horizontal section. if you got light on the crt but no sound that would be a problem in the audio section. dont forget all you will get without a converter box or dvd or vcr hooked up is static sound for audio and light and snow for video since old sets are not capable of recieving modern digital tv signals without a converter box.


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