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-   -   1975 Sears Sanyo 19" Color (http://www.videokarma.org/showthread.php?t=271611)

joe111671 05-05-2019 05:58 PM

1975 Sears Sanyo 19" Color
 
6 Attachment(s)
Found this tv at an estate sale this weekend, they just wanted it gone, so I got it free. I've been looking for an older vacuum tube style set, but this one would have been tossed so I saved it.

It's a basic metal cabinet with plastic back cover, and seems like a well made set. It was pretty dirty so I took the chassis out and cleaned everything inside and out. It looks pretty nice now.

It probably needs all new electrolytics, but there's one in the power supply to the RGB output transistors that tests dead that's causing the left side of the picture to be too dark, and the right too bright. It's more noticeable on dim scenes or when you turn the brightness down. It's a 4.7uF @ 250v - the only cap I had that was remotely close was a 10uF @ 400v of unknown age so I tried that, it went from too bright to no raster whatsoever, but the screen did have the usual white flash and collapse when powering it down, so I need to get the correct cap and see what it does. I put the original cap back in even though it tests dead, and it's back to where it was. I got the tip that it was this cap from the www.repairfaq.org website, I've used that site a lot over the years for different electronic items and it's been a great resource.

CRT is really bright, but has red & blue color bleeding (flaring?) on high contrast scenes. I know that's a symptom of a weak crt but I don't have a tester, and until I get the bad cap(s) replaced I'm not going to condemn it.

No idea what I'll do with it, but it's a cool old TV that I hope can make a good picture again.

joe111671 05-05-2019 06:09 PM

3 Attachment(s)
A couple before pictures and one after. All the components are labeled Sanyo except the CRT, it has a Sears label.

zeno 05-06-2019 10:55 AM

That cap is trouble in ALL brands. If the 4.7 dont fix it just do a
grey scale on it, someone may have fudged it to get by. These were good sets, MUCH better than a tube Sanyo. Most Jap tube sets were pretty crappy with a
few exceptions.

73 Zeno:smoke:
LFOD !

joe111671 05-06-2019 05:33 PM

1 Attachment(s)
That cap did the trick. The gray scale is perfect, didn't need to touch anything there, just had to turn the screen back up, the picture was so bright with the bad cap I had to turn it all the way down. Got the focus dialed in, it could be a little sharper but there's no sharpness control and I don't want to start turning random pots because most of them aren't labeled. The color flaring is still there, but now only if the color is turned way up, so I'm going to call it good.

Any idea if there's a way to adjust the width? It's quite a bit wider than I want it.

I might start a new thread and see if anyone's got the schematic or anything on this. There's a label inside the back cover but only has the transistor locations and I'd like to know a little more about this set.

zeno 05-06-2019 06:01 PM

Well done Joe !
Looks normal to me. It wasnt an expensive set so detail wont be
like a Zenith, RCA, Sony etc. Thats one of the things you pay for.
Be sure the main B+ is right, if high will cause wide pix. Keep in
mind with all the formats width can fool you. Try an old VCR if you
have one to judge the width. All sets will be slightly over scanned also.
Post the model ## I cant quite read it. I should have the manual if
need to dig deeper......

73 Zeno:smoke:
LFOD !

dishdude 05-06-2019 07:17 PM

Picture looks pretty solid to me. Is it me or does that cabinet look kinda modern for 1975? Could pass for the early 80's.

joe111671 05-07-2019 04:41 PM

4 Attachment(s)
Quote:

Originally Posted by zeno (Post 3211068)
Well done Joe !
Looks normal to me. It wasnt an expensive set so detail wont be
like a Zenith, RCA, Sony etc. Thats one of the things you pay for.
Be sure the main B+ is right, if high will cause wide pix. Keep in
mind with all the formats width can fool you. Try an old VCR if you
have one to judge the width. All sets will be slightly over scanned also.
Post the model ## I cant quite read it. I should have the manual if
need to dig deeper......

73 Zeno:smoke:
LFOD !

Thanks zeno! It's model 564.41701501. If you could point me in the direction of checking the main B+ I will do that for sure. I hooked up my old VCR but can't find any tapes so all I could check was the menu and it looks fine to me. I watched the set for hours last night and I swear it got better the longer it ran. I've heard of CRTs "waking up" but not sure if that's the case here or not. Either way, when I'm watching the old low resolution shows, it looks every bit as good as my 50" plasma, just brighter.

Quote:

Originally Posted by dishdude (Post 3211069)
Picture looks pretty solid to me. Is it me or does that cabinet look kinda modern for 1975? Could pass for the early 80's.

I thought so too, dishdude. I bet the design was cutting edge at the time.

TVTim 05-10-2019 10:18 AM

Quote:

Originally Posted by joe111671 (Post 3211065)
That cap did the trick. The gray scale is perfect, didn't need to touch anything there, just had to turn the screen back up, the picture was so bright with the bad cap I had to turn it all the way down. Got the focus dialed in, it could be a little sharper but there's no sharpness control and I don't want to start turning random pots because most of them aren't labeled. The color flaring is still there, but now only if the color is turned way up, so I'm going to call it good.

Any idea if there's a way to adjust the width? It's quite a bit wider than I want it.

I might start a new thread and see if anyone's got the schematic or anything on this. There's a label inside the back cover but only has the transistor locations and I'd like to know a little more about this set.

That looks GREAT!

old_tv_nut 05-10-2019 11:41 AM

No idea if there's a width adjustment.

FYI

In sets where the convergence is adjusted partly by tilting the yoke (which also affects centering), and there is no width adjustment, the set would be designed with extra width, so moving the yoke would never produce black edges. Also, solid state sets were often designed with wide retrace pulses to reduce the peak voltage on the horizontal output, another thing cutting off the sides, compensated by the extra-wide horizontal sweep. (Easier for transistor horizontal output stages to produce extra current rather than extra voltage)

zeno 05-10-2019 02:29 PM

Main B= is 120 VDC. Measure at TP30 on the bottom board on left.
VR201 is the 120 V adjust & near TP30
Width adj shows on L213 BUT it dont show a slug. It does show a dotted line
so its probably a factory jumper. I would not mess with it.

73 Zeno:smoke:
LFOD !

joe111671 05-13-2019 06:47 PM

1 Attachment(s)
Quote:

Originally Posted by TVTim (Post 3211141)
That looks GREAT!

Thanks TVTim, I'm enjoying this one.

Quote:

Originally Posted by old_tv_nut (Post 3211145)
No idea if there's a width adjustment.

FYI

In sets where the convergence is adjusted partly by tilting the yoke (which also affects centering), and there is no width adjustment, the set would be designed with extra width, so moving the yoke would never produce black edges. Also, solid state sets were often designed with wide retrace pulses to reduce the peak voltage on the horizontal output, another thing cutting off the sides, compensated by the extra-wide horizontal sweep. (Easier for transistor horizontal output stages to produce extra current rather than extra voltage)

That makes sense even though I don't quite understand the pulses, maybe because I don't have a scope and have never seen one in use. Guessing they did that to keep the horizontal output running cooler?

Quote:

Originally Posted by zeno (Post 3211148)
Main B= is 120 VDC. Measure at TP30 on the bottom board on left.
VR201 is the 120 V adjust & near TP30
Width adj shows on L213 BUT it dont show a slug. It does show a dotted line
so its probably a factory jumper. I would not mess with it.

73 Zeno:smoke:
LFOD !

B+ was a tiny bit high at 123 VDC. I let it run for 10 minutes then set it to 120 on the dot. Thanks for that info zeno. I'm going to embrace the extra width. I picked up an HDMI to component adapter to feed my Fire TV stick into the RF modulator. The extra width makes 16:9 content look better.

joe111671 05-13-2019 07:14 PM

1 Attachment(s)
Thanks for the comments and assistance guys. Now that this one is done, I have a new project. I found a couple Zeniths at an estate sale this past weekend and couldn't resist grabbing them. One works and one doesn't, but they both need help and I feel they're in good enough shape to give them a chance. I like the one on the left better, but no idea what's up with it yet so I'll focus on the working one. Needs caps at the least to get the vertical right. I'm going to start a thread on the Rectangular Screen Tube Televisions thread for this one.

Electronic M 05-13-2019 11:38 PM

Right set start by replacing the cathode lytic on the vertical output.

The left set was used at the beginning of the comedy "Groove Tube" as a replacement for the monolith in their spoof of '2001: a space oddessy'...That is one of the few monochrome consoles I'm actively looking for.

zeno 05-14-2019 08:25 AM

Keep in mind on the Zeniths the chassis comes out with the
CRT. There are 4 1/4" at the corners of the CRT.

joe111671 05-14-2019 05:48 PM

Quote:

Originally Posted by Electronic M (Post 3211243)
Right set start by replacing the cathode lytic on the vertical output.

The left set was used at the beginning of the comedy "Groove Tube" as a replacement for the monolith in their spoof of '2001: a space oddessy'...That is one of the few monochrome consoles I'm actively looking for.

Will change that for sure. Never heard of Groove Tube, and doesn't look available on anything streaming but I'd watch if it was!

If/when I get rid of the left set I'll let you know, I'm not keeping both. Looks like you're close to Kenosha.

Quote:

Originally Posted by zeno (Post 3211252)
Keep in mind on the Zeniths the chassis comes out with the
CRT. There are 4 1/4" at the corners of the CRT.

Thanks for the tip, I'm going to get started. Doesn't look obvious how it comes out as one unit, so it will be interesting to see.


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