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Hi Guys, This question has probably been asked 100 times , but I have a question about wattage ratings on some of the resistors in this chassis. resistor # 59A 70k is a bit bigger than others in this chassis so I was wondering if anyone thought the 1watt resistor would be fine. Also # 57 a 4k resistor is much bigger than the 59a resistor, anyone know what wattage I should use for it? Here is a link to a schematic ( http://www.nostalgiaair.org/Resources/814/M0013814.htm ) for it and I took a pic of the chassis, not real sharp pic, if you need better let me know.
The big yellow one on the bottom is #57 and a little ways up with masking tape marked 70k on it is 59A.
Thanks for any help, Warren
[Image: http://i1348.photobucket.com/albums/p721...qjltjf.jpg]
(This post was last modified: 04-12-2015, 05:50 PM by Warren.)
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Here's some info on Chuck's site that might help you out. On another page, Chuck has some values listed with part numbers.
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(04-12-2015, 06:06 PM)klondike98 Wrote: Here's some info on Chuck's site that might help you out. On another page, Chuck has some values listed with part numbers.
Thanks Klondike... The pictures of the resistors might help. I have seen the resistor part number page but these part numbers are different. It doesn't show these. But, according to the pictures of resistors my 1 watt resistors should take care of pretty much most. I think the yellow one in the picture might be a 2 watt according to the pictures you showed. At least I know if im using the 1 watt it will take care of any but the biggest ones.
(This post was last modified: 04-12-2015, 09:04 PM by Warren.)
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OK , another simple question for most of you out there. There are 3 electrolytic Capacitor number 67's in the power supply. Am I right in thinking the neg side of the caps go towards the center tap of the transformer? The 10uf has a ground sign on the other side but if im right the center terminal is always the most ground, correct? So I am thinking since all 3 g to the center terminal on one side that would be the side for the ground on the cap. Also cap number 52 , does the neg side go away from the resistors towards the ground sign? I know, pretty basic stuff but I don't do this everyday and just want to make sure Im not making a mistake. Thanks for any help. Schematic below.
[Image: http://i1348.photobucket.com/albums/p721...1adoln.jpg]
(This post was last modified: 04-20-2015, 01:24 AM by Warren.)
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The center tap of the power transformer's high voltage secondary is the most negative point in the radio. Let us refer to this point as B-. Because of the bias resistor (70), the chassis is actually slightly positive with respect to the high voltage secondary center tap.
All three sections of (67) have their negative leads going to B-. The 10 uF section of (67) only needs to be 50 WVDC, and its positive lead does connect to ground. The two 8 uF sections of (67) can be replaced with 10 uF caps, and they should be rated at 450 WVDC.
As for cap (52), yes, the negative lead goes to ground.
--
Ron Ramirez
Ferdinand IN
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Thank You Ron, basically that's pretty much what I was thinking so I at least was correct in where the neg leads go. I am learning here (with every ones help), slowly but surely. ![Icon_biggrin Icon_biggrin](https://philcoradio.com/phorum/images/smilies/icon_biggrin.gif) I spose I would learn faster if I could work on the radios more often, but I do what I can under my situation here. Thanks again.
(This post was last modified: 04-20-2015, 03:12 PM by Warren.)
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Well, im still trying to make sure I know which wires coming from the tube with 3 elect. caps in it are which. I think I found the 2 8uf + wires, they seem to go to the right caps by the schematic and chassis layout but still making sure on those. I also noticed there was clip with a wire that was soldered to it that just sat on the side of the metal tube not going into it or anything but touchng the metal tube. The tube is isolated from the chassis, but could this still be the ground or does anyone know different? I am thinking it is the ground but is isolated because this goes to the B-, center tap of transformer. If knew for sure this was the ground it would be easier to be sure about the other wires. Thanks for any response.
(This post was last modified: 04-22-2015, 10:44 PM by Warren.)
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no one has any ideas as to whether the wire touching the outside of the metal case goes to B- eh... Oh well , guess I will have to do more checking and hopefully I will choose the right thing . ![Icon_eek Icon_eek](https://philcoradio.com/phorum/images/smilies/icon_eek.gif) Thanks everyone anyway.
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Yes, the clip is sandwiched between cardboard insulator and the shell of the capacitor to connect the shell to B- .
Steve
M R Radios C M Tubes
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(04-23-2015, 10:22 PM)Steve Davis Wrote: Yes, the clip is sandwiched between cardboard insulator and the shell of the capacitor to connect the shell to B- .
Steve
Thank you very much Steve, it is a little confusing following the wire , doesn't seem to go to transformer.. im sure it does then, obviously just a different route. Hope I get better at tracing some of these wires, most are pretty obvious but looks like others give me trouble so far. I appreciate it.
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