06-21-2024, 08:29 PM
The Philco library will have DATA for the model you have and any possible quirks.
How to troubleshoot a "dead" receiver as a technician would instead of "Is it this or that". Go here:
https://www.worldradiohistory.com/BOOKSH...vicing.htm
This is the repository of technical books out of print on how to service. They are generic by nature meaning not specific to a model of radio but for the techniques. You can down load as needed free. The scans are PDF word searchable. A big plus for coverage on a specific problem. The Riders series of hand books are also teaching but at a technician level.
I see that this title may be more useful:
https://www.worldradiohistory.com/BOOKSH...ellman.pdf
Highly recommended:
https://www.worldradiohistory.com/BOOKSH...y-1947.pdf
On the same main WRH page is G-E tube characteristics...
Not present or possible to PDF, I suggest getting a hard copy of most any edition of RCA's Triple-Pindex. That is a vital tool to find your way underneath any chassis.
Such as: https://www.ebay.com/itm/196354059776
A huge online tube manual can be found here:
https://frank.pocnet.net/
Franks web site works well by just typing the tube type into the browser like: 7A7 pocnet then press ENTER. You will get the tube of interest.
This is Frank's Vade Mecum: https://frank.pocnet.net/vademecum0.html
More tubes than one can possibly imagine...
If one is to continue serving receivers a useful electronic tool is a circuit tracer. This can be a restored vacuum tube unit or a solid state (battery) powered unit insulated for at least 600 volts.
I could suggest simple signal tracing but unless one realizes the risk there is a real danger of shock.
However, an RF/AF generator capacitor coupled makes a good signal injector. A salvaged amplified computer speaker protected with capacitor coupling make a good receiver tracer, create a RF probe with a diode resistor coupling. Plans for a probe are all over the web.
Where you are now seems to indicate a short or mis-wire from the volume control/phono switch forward to the speaker. Some four tubes or so and about a dozen components and a rats nest of wires. Look around for a wire snip, blob of solder shorting, component on the wrong terminal. Oh, maybe a tube in the wrong socket
Be SAFE!
Chas
P.S. Beware that a DVM can tell lies about voltage and the resistance of inductors. If, you have a good VOM use it. Voltage readings printed on a schematic often have a reference text as to the resistance of the meter used to make such readings like 1000 ohms/volt. Such a meter draws a load from the circuit. A DVM draws practically nothing so it will read high and not consistently high depending on the available current from the circuit.
How to troubleshoot a "dead" receiver as a technician would instead of "Is it this or that". Go here:
https://www.worldradiohistory.com/BOOKSH...vicing.htm
This is the repository of technical books out of print on how to service. They are generic by nature meaning not specific to a model of radio but for the techniques. You can down load as needed free. The scans are PDF word searchable. A big plus for coverage on a specific problem. The Riders series of hand books are also teaching but at a technician level.
I see that this title may be more useful:
https://www.worldradiohistory.com/BOOKSH...ellman.pdf
Highly recommended:
https://www.worldradiohistory.com/BOOKSH...y-1947.pdf
On the same main WRH page is G-E tube characteristics...
Not present or possible to PDF, I suggest getting a hard copy of most any edition of RCA's Triple-Pindex. That is a vital tool to find your way underneath any chassis.
Such as: https://www.ebay.com/itm/196354059776
A huge online tube manual can be found here:
https://frank.pocnet.net/
Franks web site works well by just typing the tube type into the browser like: 7A7 pocnet then press ENTER. You will get the tube of interest.
This is Frank's Vade Mecum: https://frank.pocnet.net/vademecum0.html
More tubes than one can possibly imagine...
If one is to continue serving receivers a useful electronic tool is a circuit tracer. This can be a restored vacuum tube unit or a solid state (battery) powered unit insulated for at least 600 volts.
I could suggest simple signal tracing but unless one realizes the risk there is a real danger of shock.
However, an RF/AF generator capacitor coupled makes a good signal injector. A salvaged amplified computer speaker protected with capacitor coupling make a good receiver tracer, create a RF probe with a diode resistor coupling. Plans for a probe are all over the web.
Where you are now seems to indicate a short or mis-wire from the volume control/phono switch forward to the speaker. Some four tubes or so and about a dozen components and a rats nest of wires. Look around for a wire snip, blob of solder shorting, component on the wrong terminal. Oh, maybe a tube in the wrong socket
Be SAFE!
Chas
P.S. Beware that a DVM can tell lies about voltage and the resistance of inductors. If, you have a good VOM use it. Voltage readings printed on a schematic often have a reference text as to the resistance of the meter used to make such readings like 1000 ohms/volt. Such a meter draws a load from the circuit. A DVM draws practically nothing so it will read high and not consistently high depending on the available current from the circuit.
Pliny the younger
“nihil novum nihil varium nihil quod non semel spectasse sufficiat”
