Philco 625B Assessment (UPDATE It works!) - Printable Version
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RE: Philco 625B Assessment - morzh - 10-23-2023
....and start at an inconspicuous spot first.
RE: Philco 625B Assessment - KI5OMM - 10-24-2023
I managed to get time away from my ranching duties this morning and checked out the power transformer as described earlier. Everything seemed to work as expected. I brought the power up slowly on the variac and I was able to get around 700 volts at terminals 3-5. (see photo) Next, I checked terminals 6-7 and got 6 volts and terminals 8-9 produced 7 volts. So I guess the transformer is good and now a full restoration can begin. I will start ordering capacitors today.
I have a question for Ron Ramirez . I will be documenting the whole process probably and I need to know if I should start a separate thread for this, or should I just keep going with this thread?
RE: Philco 625B Assessment - Ron Ramirez - 10-24-2023
Keep going with this thread please.
https://philcoradio.com/phorum/showthread.php?tid=4586
RE: Philco 625B Assessment - KI5OMM - 10-24-2023
Next item on the agenda is the speaker. My radio did not come with a speaker. It has 4 wires in a bundle that came to me cut off at the speaker end. The other end of the wires are soldered to the chassis assembly with no removable plug. According to the schematic it's called a S-14? The cabinet style is a 625B. I am unsure what type to look for. Any help would be appreciated and I will place a wanted ad in the appropriate section as soon as I know what to search for.
Thanks all!
Bud - ki5omm
RE: Philco 625B Assessment - morzh - 10-24-2023
It is 36-3157 assembly with the field coil 36-3495.
https://philcoradio.com/library/download/parts/catalogs/1938/Philco%20Parts%20Catalog%201938.pdf
In this document it is says in what other radios it is used.
It is an 8" speaker widely used in many, many Philcos, so it is very likely to appear on eBay.
Look for this combination in the document, and then see if the speaker you find on eBay has the needed combination (by the radio the eBay seller would list).
RE: Philco 625B Assessment - KI5OMM - 10-24-2023
OK so I think I have this straight... speaker = 36-3157, field coil = 36-3498, and the output transformer = 32-7019
If this is good I'll start looking on eBay and also place a wanted ad here also.
RE: Philco 625B Assessment - Radioroslyn - 10-24-2023
S-14
8" cone
36-1144
610F, 610T, 620, 625 model used in. Note there is a 610B that uses the same chassis as the other 610's but the spkr is a 6" job so it wouldn't be a good match for your application.
1-42 tube as Pentode
32-7019
1 ohm VC impedance
400 output transformer resistance
1140 FC resistance
65ma FC current
It's looks like the S-7 is a good match for the unit. It was used in the Model 60 and a number of the 5/6 tube 1937 models.
That's the specs for the original spkr.
I suspect that the original spkr wiring only had three wires as the B+ side of the opt and one end of FC are connected together. The four wire cables are relegated to the set w/push/pull output stages.
If you can't find a dynamic spkr and you have to replace w/a pm spkr you'll need a 7k to vc output transformer, an 8" spkr, and a choke, the high inductance the better. You could use a resistor instead of the choke but it make a lousy filter and filter cap will have to be doubled or tripled to kill the 60cy hum.
RE: Philco 625B Assessment - Radioroslyn - 10-24-2023
I took a quick look on epay between diving under a dirty car and saw this: https://www.ebay.com/itm/235229092708?hash=item36c4bf1b64:g:tfUAAOSwX2VlFKx8&amdata=enc%3AAQAIAAAAwDWd%2FeKspAawWUxmtpCGcFapxURjgAy7U%2FKD8Urr8i9SANY5YqdAeADy7%2B46aznSzQK3lPXEoCZ85%2B3gdeVA6L59fxVOLHf%2FUGwF8Ml3i8yVlfYmRgWeu2vQGAw%2BbCjNbZyQHr2yxCQ548p8VC8zG8vdfYbXTwXXgXouhiIwm2EiiHAzfU3f3CnV7eHF7kc5ICFdS6TGZz6sqp6NtyAe8%2FZnLfi4OoiJbk4bdYu%2BQG6Qz0tJ2EBr9Orl66ZkGW8B6A%3D%3D%7Ctkp%3ABk9SR-ii_7nsYg It's a good match for the set BUT IT HAS AN OPEN TRANSFORMER. The rest look pretty average. A new opt well run somewhere between $30-50 + the ride.
There's also this one that looks all good: https://www.ebay.com/itm/235231291798?hash=item36c4e0a996:g:8BMAAOSwlF9lFixj&amdata=enc%3AAQAIAAAAwMBpRua1zcIwKTxYI8jnMKTUP3wCfSFwV46SNIHTGPvI1DVHCQ5vEn%2Bqj2PhJQtTjmSd6uzU3PJFmizLUlP8tvkee5DKQNfh9JnLVlaYaOsoS33CYktaygJrwBiztVW7Ug1DP79bKyI6JGwbDU5ZRx55m%2BmvWkGyWrJyjU4Jwd%2BiOOkr%2FKFzLUPFXJ9sKOlneX5%2B2xQ95TAtK6qpiTQTR%2BENAC87cBmyIn28il2MeNDuE9KrLEzZyOB5LNS2Jq7aJw%3D%3D%7Ctkp%3ABk9SR6rKs7vsYg
I have no connection with seller!
GL
RE: Philco 625B Assessment - radiorich - 10-24-2023
Hello KI5OMM ,
Sounds like your project is coming right along !
I currently have a Philco 38-10T on my bench .
myself I have a Philco 610B in my collection ..
Sincerely Richard
RE: Philco 625B Assessment - KI5OMM - 10-25-2023
Today I removed one of the coils to replace the old wire. All of the coils check out OK and it's ready to be re-installed.
Unfortunately the more I look at the chassis wiring, the more damage that I see. Much of the cloth wiring is badly deteriorated and broken, thereby exposing potential shorts. I also found signs of insect or rodent damage. It looks like I will end up replacing much of the wiring. I think I will use modern wire under the chassis and new cloth wire on top.
I purchased the speaker from Ebay today. (Thanks for the heads up Terry!) I am waiting on my order of capacitors and resistors from JustRadios.com
Since I am taking the chassis down this far, I may as well repaint it also. Anyone know if the tube shields are mild steel? They look to be plated in some kind of brass. I am not exactly sure where to go with that. Any tips would be much appreciated...
Bud - KI5OMM
RE: Philco 625B Assessment - KI5OMM - 10-26-2023
While getting the tuning capacitor prepared to go into the ultrasonic cleaner, I noticed something interesting. The top wires to the tubes were soldered to their appropriate tabs, but the center tab was not soldered at all. The wire was just pushed through the hole insulation and all (see photo). After removing this wire, it was apparent that it had never been soldered from the factory. Is this normal? Some kind of capacitive connection perhaps?
RE: Philco 625B Assessment - RodB - 10-26-2023
You are correct. That is a 1pf capacitor coupling the two variable caps together. It's on the Riders schematic as part 26. The parts list says "Two wires twisted together".
RE: Philco 625B Assessment - Radioroslyn - 10-26-2023
What it is there for is to add a bit more oscillator signal to input of the mixer stage by capacitive coupling.
RE: Philco 625B Assessment - morzh - 10-26-2023
Sorta the gimmic cap.
RE: Philco 625B Assessment - KI5OMM - 10-27-2023
What is the secret to getting these cans off of the coils? I can feel that the coil is loose inside of the can, but it is hanging up on something firm inside. These cans do not have a slot on the side to lock in a spacer like the larger cans do.