I recently acquired this Philco 16B code 125. It has been worked on prior and I will need some assistance from the more learned members while I attempt to restore it.
When I was taking the chassis out to clean it up I noticed these two wires attached to the transformer attached to the speaker. I have no idea what the purpose of these two clamped wires would be. If someone could enlighten me as to why they were soldered here, it would be greatly appreciated. I am still a novice at radio repair.
That's an easy one. They're for an auxiliary battery (just kidding). Actually they would connect to a remote speaker. If you follow the wires under the speaker frame they are probably connected in parallel with the speaker voice coil. The voice coil and the purple wires are connected to the secondary winding of the output transformer.
I’m just starting on the electrolytics and have an issue already. The enclosed pics show the existing electrolytic which I think is Part #91, a duo electrolytic. #1 goes to the center tap and #’s 2 and 3 go to either side of the filter choke, #4 goes to the power transformer.
I can’t locate any other electrolytic except the pic of what I think is a 4 mfd cap installed between Part #90, the large wire wound resister. Could this be the other electrolytic Part #98? If it is, how should a replacement be properly installed?
As this photo shows, I’m missing Bakelite block #97. There is another block missing as well but I’ll get to those later on. I would like get the electrolytics straightened out first.
As I mentioned, I’m new to this hobby and not knowledgeable enough to figure out what the previous owner’s have done to the radio. I appreciate any and all advice.
Here are three pics. If you need closer shots let me know. The schematic shows 12 Bakelite blocks. I have 10 in this one now and am not sure how they rewired the missing two.
The missing two is the one right above the bottom wirewound next to the transformer (right to the backelite next to the transformer) and the one right above the two missing electrolytic caps.
BTW, you are missing the wirewound heat shield, and it is needed. (see my photo)
What I would do:
Identify from the chassis layout in the documents the identifiers of the missing two backelites.
Then simply find what they were wired to in the sch and trace the wires. This is the best I can suggest.
BTW, I see big tubular cap under the heatshield is also missing.
PS. The three dark-chocolate caps at the right upper corner and one in the left upper corner just could be some of the backelite sub parts.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
(This post was last modified: 01-09-2025, 01:09 PM by morzh.)
I was trying to find that large cap that you mentioned I was missing on the replacement parts diagram. I can’t see a cap there, do you happen to have a part number for it?
Is it possible that the missing cap you referring too, is it the large cap that is soldered to either end of the wire wound resistor on my radio?
I will be making a heat shield for the wire wound resistor.
I rechecked the entire chassis and I’m also missing bakelite block 22 as well as 86 and 97. Deal with all of those later on.
It seems like I am missing electrolytic #98. Do I solder the negative connection to the center tap and positive connection to the chassis? I am assuming that the existing cap from my previous post is actually the duo electrolytic #91.
(This post was last modified: 01-09-2025, 03:34 PM by Phil27.)
If this is the first #98 8uF cap after the rectifier tube, negative is to the centertap.
In Riders you cap in question is #91, between the centertap and the GND; the Positive is to GND.
The rule: the centertap is ALWAYS negative.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Quote:I just got my parts from justradios and was going to solder in the new electrolytics but I realize I don’t know where to solder in #4 wire from my pic of the existing electrolytic #91. I should have asked when I first posted the pic.
I know #2 and #3 are the positive connections for the duo cap and #1 is the common negative to the center tap but where do I solder #4 from the power transformer.
This is simple stuff for all of you but I don’t want to make a mistake and any help is appreciated.
So, I'm confused. Part 91 is a two section electrolytic cap which should be 8 or 10 mfd. Your photo shows a three section cap and I'm not sure your numbers 1-4 are for the wires or the terminals. If the third section was wired in, the schematic isn't useful since I could not find another 20 mfd cap. Did you number the wires you cut? If so you will have to tell us where they go. I can see that two of the wires were attached to the common terminals of the can. When you say center tap are you referring to the audio interstage transformer or the power transformer?
The #2 and #3 wires were soldered to either side of the filter choke, part #96. The third section of that electrolytic was not connected. These were the two positive connections for this electrolytic.
#1 wire is soldered at the 130 ohm section of the voltage divider, part #92. I thought that was the most negative part of the radio.
#4 wire goes directly to the power transformer and I’m embarrassed to say that I don’t know why the other end of that wire is connected to that tab on the electrolytic. That tab is not one of the three 20 mfd connection points.
(This post was last modified: Yesterday, 03:49 PM by Phil27.)
OK, got it. The end terminal on the 130 ohm resistor, the power transformer center tap and wires 1 and 4 are all the same connection. There's 4 twist tabs on the cap can and they are all commonly attached to the can making them all the same potential. So, the wires 1 and 4 are at the same potential because they are soldered to the twist tabs. The schematic shows this; start at the center tap, then to the negative of the caps (which is the can) then to the 130 ohm resistor then on to the rest of the circuit.
I’m still confused though. When I connect my two new caps, do my + connections go to where #2 and #3 wires went. I’m assuming the - connections of the caps go to the center tap. Do I connect #4 wire from the power transformer at the same place? Sorry for not understanding but I still don’t get why that wire, #4, is going to a tab on the cap. I haven’t seen that before in my brief experience in radio restoration.
Please correct me if I’m wrong but I’m trying to get an understanding of the schematic. Are the 2 electrolytic connections on this radio, the 2 8mfd caps parts #98 and #91 on either side of the filter choke? I seem to be missing the other section of part #91, the 10 mfd with positive to the chassis. I can’t find another electrolytic on the chassis.
I can refinish a radio cabinet beautifully but my understanding of electronics is deplorable and at 75 years of age I need the”dummies for electronics” explanation. I hope you all can understand. Thanks.
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