noobie wow!!!! overwhelming. HELP - Printable Version
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RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-09-2015
(11-09-2015, 03:28 PM)OZ4 Wrote: On the 80 rectifier measure the voltage from cathode to plate that's on the transformer #6 to #9 also measure from cathode to chassis ground. What are these voltages?
On the 80 tube there are 4 pin F-F (the larger pins) and P-P (the smaller pins) I measured them in the chart before. (the P-P) is the plate to cathode) right? as for cathode to ground how do i measure that? I assume one of the smaller pins to ground and does it matter which one. Is this right. This is my first radio and I'm doing a lot of research but still way behind you all.
thanks ken
RE: noobie wow!!!! overwhelming. HELP - OZ4 - 11-09-2015
No P-P is plate to plate that should be an AC voltage. P-P in the transformer voltage chart.
On the 80 tube P-K would be from either one of the bigger pins to either one of the smaller pins and is a DC voltage.
From the drawing it shows the larger pins are the filament which is also the cathode. (that's K for cathode)
The voltage I would be interested in is across the #60 filter cap which is also the output of the power supply and is not in the chart.
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-10-2015
OZ thank you I had read earlier about the cathode being in with the filaments sometimes and forgot. I ve been trying to figure out why I had 700 something readings.....P-K 348 or 355 depending on which pair you put together. I was wondering you said measure off the #60 which is a bakelite off the tone control is that a separate measurement? I tried to measure that and got a mild loud hum and a little smoke from #9 bakelite or #43 input transformer. not sure which one. #9 capacitor looks ok and feels ok. The ac volts on # 60 bake lite to tone control was like 1.5vac and dc was low mV. Another Question was 0n the chart for sg-K... 3 of the readings were supposed to be 80 and were way high... any suggestions there. Also to let you know my shadow meter is open...coil has a break some where. I'll try fixing it sometime also.
Thanks again
KEN
RE: noobie wow!!!! overwhelming. HELP - mikethedruid - 11-10-2015
Ken, there are a LOT of resources available on Nostalgia Air that may be of help to you in learning to repair antique radios. This is a link to an old NRI course on radio repair that may be of help top you, especially the parts on power supplies. http://www.nostalgiaair.org/References/Articles/nri/index.htm . Best of luck.
RE: noobie wow!!!! overwhelming. HELP - OZ4 - 11-10-2015
We must be looking at different drawings. On the 18 code 124 drawing the #60 cap is part of the power supply. In any case it sounds like its working properly.
a little smoke from #9 bakelite or #43 input transformer does not sound good.
Again what drawing are you looking at?
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-10-2015
(11-10-2015, 10:02 AM)OZ4 Wrote: We must be looking at different drawings. On the 18 code 124 drawing the #60 cap is part of the power supply. In any case it sounds like its working properly.
a little smoke from #9 bakelite or #43 input transformer does not sound good.
Again what drawing are you looking at?
I am looking at the 18 code 121 which is a little different than the 124 Not much though. I have the 124 and I see where you were coming from. On mine it was#54 elect. cap. As for the smoke i cant find any thing. I m not sure if it was just warming up some wax. it hasn t done it since..... There wasn t a strong smell of burn with it and everything seems to stay cool. Did you have any ideas about the sg-k measuring high on the chart posted before.
Ken
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-10-2015
(11-10-2015, 09:25 AM)mikethedruid Wrote: Ken, there are a LOT of resources available on Nostalgia Air that may be of help to you in learning to repair antique radios. This is a link to an old NRI course on radio repair that may be of help top you, especially the parts on power supplies. http://www.nostalgiaair.org/References/Articles/nri/index.htm . Best of luck.
Thanks for the link I'll take a look at it...some things are hard to find.
ken
RE: noobie wow!!!! overwhelming. HELP - OZ4 - 11-10-2015
On the 75 and the 6a7 tubes the P-K voltages are a balance between the bias voltage and the load resistor. There must be some bad resistor values related here.
First what are the bias voltages on these two tubes?
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-10-2015
What readings are you talking about? ac measurements on k-p ? screen grid ? I'm new to this you'll have to explain. Sorry
what readings you want.
RE: noobie wow!!!! overwhelming. HELP - OZ4 - 11-10-2015
Mesure the DC voltage on the 75 the grid cap to ground
and the 6a7 Pin 5 to pin 6 the K cathode.
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-10-2015
75 the grid cap (on top of the bulb) -1.49v........g1-k 16.1v
RE: noobie wow!!!! overwhelming. HELP - OZ4 - 11-11-2015
Can you post a better copy of the schematic? The one that's up now is mostly unreadable.
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-16-2015
[Image: http://i1380.photobucket.com/albums/ah182/laipplyken/philco%20pics/Screenshot%2011_zpsy486pbic.png]
I have a bad wirewound resister and wanted to know can you rewire them. How hard is it?
RE: noobie wow!!!! overwhelming. HELP - laipplyken - 11-18-2015
Where can you buy this wire wound resister? I got one response and he only had a 3500 ohms an a 3000 omhs that i could put in series....Not sure if it was the same kind though. I would like to keep the same look. Any one have any ideas?
RE: noobie wow!!!! overwhelming. HELP - klondike98 - 11-18-2015
The only place to get one that is a match in looks would be from another chassis. You can buy resistors with the appropriate wattage as replacements but they will look different. I see you put in a Wanted Ad so hopefully one will turn up.