I have pulled all the tubes and it pulls .45a at about 40vac and my dim bulb lights up pretty good don't dare go higher. My tube line up is
2- type 52 bulbs .2a each
So 5Y3 5v @ 2a
6.3v 2.05a on the others
340vac to center tap so 680-700ct?
I'm looking at some Hammond info and I think the 273DX might work I'm I on track What have I left out ???
I have recapped my Philco 90A (early model w/45 push pull tubes) and replaced a couple of out of tolerance resistors. All tubes check good, all shields in place, bakelites restuffed. I am receiving 2 stations very clearly, the loudest is close to my home, the 2nd is a little farther away and not as loud but still easily hearable. After this I have to really strain to hear other stations. Is this all the volume I can expect on farther stations with this radio? I am using a 100' wire antenna 25' off the ground. My RCA 17K is picking up a 1000w station 30 miles away right now like it is next door. Have I missed something? Thanks for all suggestions,
An older gentleman friend here in town runs a shop, and has this interesting piece in storage. My guess is it's a custom job someone very expertly put together as a PA system. Any thoughts anyone? Can anyone tell what chassis this might be
I am relatively new to the electronic restoration and understanding of these old sets, so bear with me here. I can solder, replace parts, caps, controls, use a multimeter, but as far as understanding, processing, and diagnosing electronic issues, I am a novice. I have been reading up on things to check and do when it comes to the electronic restoration of these sets and understand most of it except that I have not found a good description of how to actually check B+ voltage or what this even tells us. I have a vague idea, but no hypothetical light bulb has gone on for me with this. I have 2 very similar sets doing different things and I was going to try and attach these sets as real world applications involving the testing of B+ voltage and what this can tell me in these 2 cases, if anyone has the time to explain.
Case#1. Philco 37-610 - recently cleaned, replaced bad volume pot and all caps including electrolytic, filter bakelite, and paper with correct values, above recommended voltage ratings, and good clean solder connections. The electrolytics used were older unused multisection can types that tested good before installation. After all this and checking tubes as well, the set played with no hum or distortion, however volume level was not as high as it should be, not many stations picked up on the am band (more came in with the short wave band), and after 1/2 hour of playing the volume dropped dramatically, a burning smell started, and after shutting off I noticed that one of my multisection electrolytic caps was physically leaking out the bottom of the chassis.
Case#2. Philco 37-630 with shadow meter - recently acquired from someone who just replaced all the electrolytic, filter, and paper caps, and power cord. Tubes were supposedly checked and tested good. Previous owner said that the set still slightly hums, no stations come in and no static or volume at all, just silence, and that the (metal) 6f6 power tube "overheats". He had mentioned that this made him concerned about the power transformer. Can someone help me to understand how he came to this diagnosis and how an overheating power tube can point to the transformer, or if this guy really has no idea what he is talking about. . .
I want to learn to be exact and knowledgeable about this, not just throw parts at it until it works.
Thanks in advance
In case you are wondering...the 4230 is fixed. No more distortion.
The culprits? Transistors H706 and H707. Base and collector were transposed on both.
The datasheet for those transistors gave incorrect pinouts for that transistor type.
From now on, before installing new transistors, I will check them with the diode test on my multimeter to make sure what the datasheet says is the base really is the base. I will then test the new transistor on my transistor tester to make sure that the emitter and collector leads are also what the datasheet specifies.
Many thanks to Phorum member Ed L. for his help in getting this problem solved.
I am nearly finished restoring a 1936 Philco 60, the last version before
the model 37-60. I'll leave the details of the restoration at the end of
this post. The problem is the oscillator does not work and the radio is
mostly quiet after applying power, however, I can "jump start" the
oscillator and the radio comes to life. When not oscillating, the screen
grid on tubes 6A7, 75, and 78 are very low about 10 to 15 volts and
resistor #14 (32k ohm) gets very hot with a voltage drop of 260 volts
which is near its 2 watt limit. When it is oscillating and working
properly, the screen grids are about 60 to 70 volts and resistor #14 is
about 150 volts. On a weak station, the radio will play for a little
while then the oscillator will cut out. But, a "jump start" will bring
the radio back.
What is weird is that I can "jump start" the oscillator. To do this, I
have unsoldered the lead to capacitor #13 and the output of the
oscillator coil and reconnected it with a jumper cable. This was done to
see if I wound the output coil backwards. I noticed when disconnecting
then reconnecting the jumper would break the silence on the radio. I
think that bit of static from reconnecting the jumper would kick start
the oscillator. I can then power-off the radio briefly, and turn back on
(within the time the filter caps have not fully discharged). Does
anyone know why this is happening? I can't figure out a fix for this.
The attached schematic will show a red oval around where the jumper is
applied. I can provide a video on Youtube if anyone wants to see this.
In the restoration, the radio was re-capped. The two 8 MFD filter caps
were replaced with 10MFD caps. The bakelite condensor blocks were all
re-built with new caps. The multi caps in the metal can were replaced by
a terminal strip with appropriate caps. The shortwave portion of the
antenna coil (approx 0.7Ω) was re-wound, and the 3.4Ω portion of the
output oscillator coil was also re-wound thanks to the information from
this Phorum and other Philco sites. Initially, the 8MFD filter caps were
replaced with 16MFD caps, and thinking that possible the oscillator
needs some slight ripple to start, we have since replaced the 8MFD
filter caps with 10MFD. There was no change to the oscillator. I've
since went back to the 16MFD filter caps.
I have the original labels on a 70 Cathedral on the tube shield, look very worn and one has a small piece missing in corner.
Another label is partially lifting in a corner and would have to be reglued.
Would you keep the old labels and how would you protect them from further decay ? Contact paper maybe (yuck).
Would it be best just to scrap the old labels and use repro's ?
Hi guys. I just did a complete electrical restoration on the 1939 Philco console and it has hash noise across the broadcast band. It's present on the shortwave band, but not as prevalent and it varies with the volume pot. It's not smd with this if can type. This was a bare chassis up restoration and I did a triple check against the schematic on the wiring and component values and all look good. All caps, except micas have been replaced, along with most of the resistors. I also performed an alignment procedure more than once. So now I'm wondering if there may be some critical wiring paths to be aware of. Or maybe a faulty tube? A leaky new cap? I have test equipment, including a scope, but I'm not sure how to trace and isolate this problem.
Any help would be appreciated.