#31
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Could be a manufacturing issue with the coils since some set fall flat and others only stumble a tad...
I'd make my own DC-DC converter, in your shoes. You just need a simple 555 osc. chip (and some R's and C's for it), a power FET, and a flyback from a junk BPC set. I built a 30KV plasma speaker that way with cheap parts and junk, and I'm sure I could de-tune it to produce 4-7KV.
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#32
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I'm getting to know the chassis. I'm studying the schematics and parts layout. What I like to do is to mark each component with a little piece of masking tape the Item number from the parts list. I did all the Bumble Bee, paper, and square mica caps, the high voltage circuit resistors, the high wattage resistors, and high value resistors for now.
I enter the resistor and capacitor parts lists into Excel. Then I can sort them and it helps me come up with a replacement parts list that I need to order. While doing that I came across a connection that wasn't soldered! The lead from the resistor just pulled up from the pin on the tube socket. While there was ample solder on the tube pin, the resistor was missed in that it never got a good solder joint. I think I have a later run for this chassis. My Sams 140-7 shows the components, but I have more terminal strips and slightly different locations for some of the components. So far I've found all the components that I've been looking for. Yes, some of those pesky 1/2W carbon comp resistors can hide very well, very well indeed. Some of the paper caps shown in the Sams are Bumble Bee caps in mine. Last edited by Crist Rigott; 12-07-2016 at 01:12 AM. |
#33
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Yes anything is possible and maybe even the lack of enough b+ due to design although when new components were new but now so many decades later where all the components are tired and given Alittle more b+ things may be different since if these sets share these hv problems I'm sure everything has since been checked out and ok. Even resistors and coils that have resistance that is higher after so many years then that's ok if the set works but after a certain amount of time things happen, heating, but if this was multiplied several times over the whole chassis, who knows. Ah just thinking out of the box.
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#34
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After spending some time looking over this chassis I think everything is original. Nothing has been changed except for a few tubes. The picture tube is a Philco too.
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#35
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Did you get the 7jp4 tested on another set yet ?
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Audiokarma |
#36
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I contacted my friend and we'll get together next week and check it out. I think he mentioned he does have a replacement, though I can't recall directly. Untill then I'm just doing some homework and putzing. Won't order anything till after that.
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#37
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Hey, just a shout out, I'm looking for the Philco Service manual for this TV. It's a Philco 50-T702.
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#38
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The ETF website has the Sams for it. Here is a link to the page that includes the Philco sets Sams you can download:
http://www.earlytelevision.org/tv_sc...-p.html#philco Dave |
#39
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Quote:
Thanks for the info. I already DL that Sams. I'm looking for the Philco Service Manual by Philco. |
#40
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After spending some time looking over this chassis I think everything is original. Nothing has been changed except for a few tubes. The picture tube is a Philco too.
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Audiokarma |
#41
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I'm going to get the CRT tested tomorrow with a working set. A full report when I get back!
If all goes well, then I'll order the parts that I need. |
#42
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The CRT 7JP4 tested good to very good! We could easily see the picture with the lights on.
I still have to figure out a way to get the metal sleeve off the neck so I can re-glue the base. It has just a little movement to it. I'll order up the resistors and capacitors and will press on with the restoration. Anybody go knobs for this TV? Last edited by Crist Rigott; 12-07-2016 at 01:17 AM. |
#43
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I see JustRadios has the .0047uf 6Kv caps. Are there any other suppliers?
Thanks. |
#44
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Allied has a selection of 6000 & 8000 volt ASC capacitors.
http://www.alliedelec.com/passive-co...281-4294965387 |
#45
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I found a source for the HV capacitors.
I have most of the resistors and some of the film caps so I decided to replace what I could till the rest of my orders come in. One of the first things I did was to clean up the mess that had happened from Philco's famous black tar/wax that had melted down to underneath the chassis. While I was at it I removed the phenolic pot board to aid cleaning up the mess and to clean up the pots. After several hours the mess was cleaned up and the pots were cleaned and fully checked for smooth operation with no bad spots. I then installed everything like before. I then replaced some caps and resistors along the terminal strip behind the rear pots. I'll replace what I can with what I have for the time being. Last edited by Crist Rigott; 12-07-2016 at 01:23 AM. |
Audiokarma |
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