Philco Mod. #44" Need help"
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I'am going to restore my 44 philco and could really use some advice on how to procede. So far I built a dim bulb tester and powered it up with tubes out to check the power transformer. The bulb stayed very dim as it should. I put the #80 tube in and had the same results. went to 100watt bulb and it did'nt glow very bright. So I powered it directly from house 120v. The 80 tube got very red with a purple tinge. so I unplugged it. I have ordered all the caps to replace have been studying the schematic and found there are 3 caps in chassis not on schematic.Should I replace all the caps or is there certain ones to do first to address the #80 tube?
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Are the three caps not on the schematic replacements installed by someone in the past?
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I beleive so. one of the electrolytic can cap is cut it is a 8-8-10 mfd. the wire now goes to 2 capacitors one is a silver box about the size of 2x3inches it is 8mfd and another tubular cap that is 10+10mfd these appear to be very old though. The othercap not on the schematic also very old is connected across the bc wire wound resister that is 263ohms&21ohms that cap is a 10mfd. all of these caps that I mention are electrolytic. Added note while waiting for a response about my question I changed the 80 tube and did the dim bulb test again. This time the 100w bulb lit up very brightly so I quickly shut off power. according to the instructions I have about this test it means I have a short circuit in the filter capacitor of power supply. Does that sound right to you. Thanks for taking time to assist me. I'am new to this and want to take my time and do this correctly.
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Mike,
The next step is to replace the filter capacitors. You should replace the line filter capacitors item 68, if shorted, you could have a hot chassis. Also replace capacitors 48, which if leaky can damage the output tube or the output transformer. Bad tone control capacitors can also damage the output transformer. After these capacitors are replaced, you can begin troubleshooting the radio without too much worry about damaging other components.
Steve
M R Radios C M Tubes
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Thank you for that info. It's great to have a starting point. Will post again when completed with these first steps.
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The model 44 (and it's successor, the 144) are, in my opinion, two of the better receiving six-tube sets out there. Your 44 is worth the effort you are putting into it.
ALSO: one of your electrolytics has a cardboard sheath on it. (#67). It is the one that has two 8mFd caps in it. The negative sides do NOT go to chassis ground.
Your other one (#69) is the 6mFd, the negtive side does go to chassis ground.
Don't rely on what a former "technician" did to your set, as too often they are ...."misguided."
There are several smaller value caps in your set that are connected to B+ in various manners. It is never a bad idea to replace them. Remember, they are 70-plus years old. If you intend to play the set as it was intended to be, strongly recommend that you replace them.
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Thank you for that info. I plan on replacing all the caps including the rebuilding or bypassing the bakelites there are 6or7 of them. I do have a question. There are 2 metal condensor blocks in the chassis one has 7 wires comming out of it and is listed on the schematic. with the MFD. The other can listed as condensor metal can 25MFD its #55 on the schem. I was looking for a cap in that value at different sites and I can find 22or33MFD Mygoodness 24.00 for that value of cap. or am I reading something wrong and it is a .25cap? By the way the #67 can 8-8-10mfd has been bypassed and the caps to it are 2 of the ones not in the schematic. one is a10-10 tubular cap and the other is the cardboard box thatsays 8mfd these are stuffed down in the chassis side by side.I did notice that can was insulated from the chassis thats where someone disconnected the wires from the can and just soldered them together and that wire runs over to the 2 caps I just mentioned.I will have to follow up on exactly where how those cap are connected and to what. Now the #69 can ,my schem. shows it as #71 6mfd. is still hooked up. I put a ohm meter on it from the center tab to ground and no reading but I plan to replace it also.
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The metal can under the chassis is 0.25mFd.
The capacitor bank should be re-stuffed. Sometimes the insides come out easily, sometimes they don't. There are several threads here about different methods for re-stuffing them.
Recommend you re-stuff the bakelite blocks, as they also serve as "tie-down" points for the radio circuitry.
I just simmer water in a pot I never intend to use for food, and let the bakelite block sit in the hot water until the wax is soft enough to pry out.
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Thats good news on the .025 can. I'll follow your advice on restuffing the bakelite blocks. I did read an article on how to do that I believe at Philco repair bench. I've ordered a schematic from Mr. Schwark that should help me to see better than the little one I've been using. Have'nt cut or unsoldered anything yet just studying all info I can get and getting a plan together. Many notes and pictures first along with great advice from this forum gives me the confidence to get this project done right. Thanks
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Thanks TA Forbes for the correction. Iwas starting with the tone control ,the shaft is broken off even with the the nut. I unbolted it from chassis and discovered something is missing ,on the contact area you can see where it's shiny but nothing there. The part # is30-4168 after a lot of searching I found one that is Philco 45c part#30-4178 . Would you know if that will interchange? Thanks
I found it on a link from the philco site and will have to order it and there is no picture.
(This post was last modified: 11-29-2012, 10:12 PM by KCMike.)
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Still working on my Philco. I have rebuilt 5 of the bakelite blocks with 2 to go. The next one I'am working on calls for 2 .0001 twin caps. Can I use 2 - 0.001 caps instead? Thanks .
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You should stick to the original value. I believe those are two cap in the 2nd detector used as a rf filter. Should be 100 or 120 mmfd mica caps. On the tone control you could replace it with a 250K- 1M pot and a .05 630v cap and have a variable control rather than the switch.
Terry
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Thanks Terry : I"am glad I asked the question. I have a couple 100 mmfds I'll use. On the switch, thats a good idea. I have ordered a tone control and waiting for delivery if it doesn"t work I'll give your suggestion a try. Mike
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I have finally finished rebuilding the bakelite blocks and getting ready to replace the electrolytics. The 6mfd can capacitor. Can I use a #10mfd in place of the 6mfd ? Thanks Mike.
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