51-934 code 122 - Printable Version
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philco4me - philco4me - 09-11-2025
Now the the chassis issue is solved I have no am or fm. I was Able to hookup a Bluetooth so I know The amp is working fine. The schematic calls for a signal generator but I do not own one. What do I check for radio issues ?
Thank you.
RE: 51-934 code 122 - bridkarl - 09-11-2025
Not sure what you mean by “radio issues”
RE: 51-934 code 122 - philco4me - 09-11-2025
Yes sorry I have no am/fm sound. I hooked Up a loop antenna but get nothing on am/fm
RE: 51-934 code 122 - David - 09-11-2025
Take a working radio let it warm up for 5 minutes having placed near the 51-934 and tune the working set to a place on the dial with no stations start with the AM band. Allow the 51-934 time to warm up 5 minutes then tune to the same place on the dial as the working set may have to turn the dial a little to get them to match. Let us know what happens. David
RE: 51-934 code 122 - philco4me - 09-13-2025
Thank you for the help. Before I do That I noticed one of the 12ba6 is just broader line weak/good so before I do that test I have Ordered a replacement tube. The rest of the tubes test good. I will Keep you posted when the tube is replaced and I will try what you suggested.
RE: 51-934 code 122 - bridkarl - 09-13-2025
Well tubes are rarely the first thing that is wrong. Your tube tester probably is just an emissions type tester which will give you a rough idea of condition.
I’d do what has been suggested before just swapping parts. You don’t want to introduce problems.
I’d try isolating the issue to a particular stage and going from there. Plenty of books available on the subject
RE: 51-934 code 122 - philco4me - 09-13-2025
Ok thank you. I will Do what was suggested first.
RE: 51-934 code 122 - philco4me - 09-15-2025
Going to do this test tomorrow. Since it is not in the case do I need To put the antenna back on ? If so I will But it back in the case and attach the antenna wires
Thanks much
RE: 51-934 code 122 - David - 09-15-2025
Try without the case no ant just make sure to have the sets next to each other. Please be careful since one is out of the case safety first. David
RE: 51-934 code 122 - bridkarl - 09-15-2025
What I normally do with these case mounted antennas If you need an antenna is just run two jumper wires with alligator clips from the case to the antenna wires on the radio. I assume you unsoldered them and they are just sitting
What David said will work for this so do that.
Just do not be touching the chassis. Preferably you have a variac so you can bring it up slowly.
One hand in your pocket and all the safety rules followed. If you have an ammeter that’s also useful.
RE: 51-934 code 122 - philco4me - 09-15-2025
Thank you for the safety. I have Been wearing a rubber glove and non-metal if I touch Anything.
RE: 51-934 code 122 - bridkarl - 09-15-2025
Rubber gloves won’t be useful. They’ll just vaporize. Like I said just try to set everything up and never touch the chassis when the power is on. Capacitors can also retain a serious charge.
RE: 51-934 code 122 - MrFixr55 - 09-16-2025
Hi Philco4Me,
With tubes other than power output tubes, not much goes wrong other than low emissions, dead due to open heater (filament) or gas. A "weak" 12BA6 will generally not cause a dead radio. If this radio did not work before you started (I believe you stated that it would trip the breaker), failure to operate is usually caused by only one failure EXCEPT:
- Parts that fail while the radio sits in storage such as electrolytic and other capacitors.
- Connections that fail due to oxidation (rust, tarnish, corrosion, etc.) while the unit is in storage. This includes open transformer and coil windings.
- Wiring mistakes while replacing parts, wires, etc.
- Poor solder joints, solder splashes, "bridged" connections (caused by too much solder connecting 2 joints that are not supposed to be connected).
God bless you, you jumped into the deep end of the pool on your first swim. This is a rather complex radio, as opposed to a simple 5 tube AC-DC AM radio, but you are doing well so far.
Do you hear anything on either AM or FM? And by anything, I mean hissing, static, squeals while turning the tuning dial, etc.?
How is the Bluetooth installed? Was there a "Phono" jack on this radio or did you wire it in. Is there a switch between Bluetooth and radio? If you can send a clear picture of how you wired in the Bluetooth adaptor.
Try the following: ALL previous warnings about protection from electric shock still apply!!!
- With the set on, confirm that all tubes are lit.
- Slowly turn the band switch between AM and FM. Wiggle the bands witch. There should be quite a bit of noise as the band is changed. If no noise, further investigate how the Bluetooth adaptor is installed and check the connections to the band switch from the AM Detector and FM discriminator. If you have DeOxIt D5 Contact Cleaner, use it to clean the band switch. Return the switch to AM.
- Take a meter lead not plugged into the meter. Attach a 10 ft piece of wire to it. Nothing on the other side. It is being used as an antenna of sorts. Put the band switch into AM.
- Touch the probe to pin 1 (grid) of the 12AU6 2nd IF. You should hear static or hum. If not, there is a problem with that stage or the detector stage.
- Touch the probe to pin 1 (grid) of the 12BA6 1st IF. You should hear static or hum. If not, there is a problem with that stage.
- Touch the probe to pin 7 (Mixer grid) of the 12AT7 Osc Mixer tube, and attempt to tune in stations. You should have either tunable noise or actually pick up stations.
To troubleshoot each stage, start out by measuring between the chassis and the plate of each tube / stage of the RF Amp, Osc. / Mixer and IF Amp tubes. Concentrate on any stage where the plate voltage is either very high (open circuit in a transformer, cathode circuit or miswiring) or very low (short circuit, open dropping resistor, miswiring.
Finally, carefully inspect all wiring, solder joints, etc. Pay close attention to the condition of the band switch. With the radio unplugged, check continuity of primary and secondary coils of the IF transformers and oscillator coil.
You have done a lot already on a complex radio. You have cleared the short in the power supply and have gotten the audio circuit to work. Next, concentrate on getting AM. When that is fixed, then try to get FM (this may be the hardest part.)
Again, good luck and congrats on progress so far.
RE: 51-934 code 122 - philco4me - 09-16-2025
Hello
There is a service port in the back of the radio that I am Using for the Bluetooth. I have Used this on some Philco radios and have had no issue. I get do get static when moving the am/fm. One band is has no sound and the other is like a popping and noise. I am Guessing that’s the AM. I will Continue to do the testing you have provided and thanks you for your help.
RE: 51-934 code 122 - bridkarl - 09-16-2025
Just as an observation-I have had several radios where the issue was the bandswitch. It sits for years oxidizing so cleaning really helps. I use lint free qtips designed for watch repair. Do not just be spraying deoxit into the switch as the wafers are often phenolic and can be damaged.
That’s a complicated radio so good for you.