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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Dec Thu 13, 2018 12:51 pm 
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Joined: Nov Wed 30, 2016 7:35 pm
Posts: 4387
Location: Sunbury, Ohio 43074
Kent, I can do both. PM on the way with Email. The higher the resolution you can send me the better. I can convert it to whatever works best

Barry

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Preserving the history of electronics, one boat anchor at a time! :)
www.bbtvtestequipment.com


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Dec Sun 16, 2018 5:27 am 
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Joined: May Wed 18, 2011 2:40 am
Posts: 3930
Location: Littleton, MA
I've uploaded Kent's scans of the manuals for the Polymeter Type 134 and Polymeter Type 134Z to my site, ko4bb.com, and ebaman.com. I've started the process to upload them to mods.dk.

http://www.byan-roper.org/steve/manuals ... 20Book.pdf
http://www.byan-roper.org/steve/manuals ... Manual.pdf

I've also uploaded Kent's scans of the Polymeter ad from the December 1946 issue of Radio News and a Sylvania Polymeter sales brochure to my site.

http://www.byan-roper.org/steve/manuals ... 201946.pdf
http://www.byan-roper.org/steve/manuals ... ochure.pdf

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Steve Byan http://www.byan-roper.org/steve/steve-at-play/


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Tue 04, 2019 7:40 pm 
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Joined: Aug Sat 02, 2014 3:59 am
Posts: 1148
Location: Brooklyn, NY 11217
I am digging this up because I went back to working on this. The first issue I discovered that I needed to correct was that only one of the HV windings was connected inside the transformer. I opened that up, replaced the wire lead and now have power to both sides of the 7Y4 (reading 620v without load). However, my meter still will not center and will also swing wildly on anything but ma and + volts. On positive . I took out the rectifier and it does the same thing. I am not sure how that is possible yet. If I pull out either of the 7N7s, the behavior stops (I am sure you are shocked). I have to change the 4900 ohm pot (though that reads fine) with a 5k. Once that is done, the only original pots left will be the ohms pot and the 2M pot. Neither of which are connected across the the board (absent leakage in the switch), so I have some sluething to do.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Wed 05, 2019 3:43 am 
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Joined: Aug Sat 02, 2014 3:59 am
Posts: 1148
Location: Brooklyn, NY 11217
Looks like I have to go through the resistors again. Playing around more, I got the RF volts to zero by dialing the cal pots all the way down and the zero pot all the way down. It stopped swinging by getting closer to calibrated. And before you ask, the 7N7s are pretty well balanced on my TV-7. Regardless, I am glad I solved the power transformer issue.

Does anyone have a picture of their turret panel board? I was looking at my before and after pictures on my board. I was tracing the schematic and noticed an anomaly in my wiring, but looking at my original pictures it was the same way. The negative side of C-106 runs to a turret connector. Two wires are connected to that same turret. One runs to ground. The other runs to an empty turret. That seems wrong to me. No production unit would use a wire to nowhere. So if you have a picture, I would love to see it. I need to take more time and trace in the coming days.

Shawn


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Wed 05, 2019 7:15 am 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 238
I used to have a Sylvania green VTVM. I really liked it; its smooth and clean operation made it a joy to use. Unfortunately I left it behind when I closed my shop in 1985. I did have the rf probe.

It was stable and accurate. I probably should have used it more.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Wed 12, 2019 2:48 am 
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Joined: Aug Sat 02, 2014 3:59 am
Posts: 1148
Location: Brooklyn, NY 11217
Well, another unit on the board has the same wire to nowhere mine has. I am considering adding a bit more resistance to the meter to see what happens. I don't really know what else it could be at this point. I am 1/2 way through the retrace of the schematic. Just don't know where to go next really.

Shawn


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Wed 12, 2019 4:16 pm 
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Joined: Aug Sat 02, 2014 3:59 am
Posts: 1148
Location: Brooklyn, NY 11217
For those following along. This wire is connected in the circle, but does not connect to ground or go anywhere else.

Attachment:
Turret Mark.jpg
Turret Mark.jpg [ 130.56 KiB | Viewed 148 times ]


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Wed 12, 2019 5:56 pm 
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Joined: Jan Tue 10, 2012 8:39 am
Posts: 238
Back in the day, often M was used for 1000. That was later changed to k, with M being used for meg. So finding a 16000 Ohm resistor marked 16M was the way it was often done.
After all, M is Roman numeral for 1000, while k comes from kilo, also meaning 1000.

I remember hearing on an FM station the term Megahertz used for the first time. My ears perked up and I thought gee that sounds affected and awkward. Now of course it's universal, and no longer is the archaic term megacycles used. It was wrong anyway, as it should have been megacycles per second.

Another term that hasn't really gotten enough use is Siemens, the old name being Mho. And I have seen plenty of Youtube videos where the perpetrator says that an open circuit has no resistance, when in fact it's the opposite.

It used to be called AVC but that's been supplanted by AGC. Times change, and we need to be flexible enough to see that and to upgrade our communication skills.


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 Post subject: Re: Sylvania Polymeter type 134 designed by my dad
PostPosted: Jun Wed 19, 2019 4:39 am 
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Joined: Aug Sat 02, 2014 3:59 am
Posts: 1148
Location: Brooklyn, NY 11217
Think I found my issue. I was probing the b+ and tapped the negative side of the B+. in doing so, I found that the meter moved. TUrns out that there was a strand of wire bridging the turret to ground on the board holder. I thought I had solved the issue. Meter calibrated to zero on DC + and -. I thought I was golden. It was up for about 5 minutes where there was a poping sound and a smell coming from the power transformer. Looks like I have another part to replace. Sigh... I thought the resoldering would save it. Guess I was wrong. I have a transformer I may try to slot in. It's 700VCT instead of 600VCT. I may exceed the plate voltage on 7y4 though. I may need to look for a new transformer.....


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