Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

Thread Closed
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Philco model 49-900
#5

Hi Tonto. The thread has very good suggestions. I am a big believer in "Divide and conquer" troubleshooting.

Before anything else:
Caution! This radio is a "Hot Chassis (even if isolated by a capacitor) with a very real shock hazard. Worse yet, the power switch switches the neutral instead of the hot connection. Either use an isolation transformer or use a meter to ensure that the chassis is at neutral (ground potential by checking voltage between the chassis and ground. If voltage reading is near 120V then reverse the orientation of the power plug. Check agin for a low voltage between chassis and ground. Do not turn the switch off or then the chassis becomes hot again due to the continuity of the tube filaments.

If U wanna get down and dirty, look at the schematic from Ryders and break the connection between the volume control and the detector stage. connect a source such as an MP3 Player. If the sound is good, this eliminates the power supply, volume control and amplifier section. If this is not the way you wanna go then:

First test- Turn down the volume control and smack the radio around (Tap individual components with non metallic object). Static? Then check volume control, Power Supply(Including filter and all 'bypass' caps and Audio Section If good, then:

Second test- Set the Tuning Cap (Capacitor) to full open (1700KHz). Vary volume control. Static? If good, leave volume control high. Smack radio around Static? If so, then check connections, tap individual tubes, components, etc. If no static, then:

Third test- Slowly tune down till the first station is heard. Static, if not, then continue tuning downward. If static starts as the tuning cap plates start to mesh, tune up again and then tune back down. If the static starts at the same place on the dial scale the the tuning cap has dirt or aluminum oxide between plates or the plates touch.
One method is to take a feeler gauge and run between the rotor and stator plates. then blast with canned air or leaf blower. Also check the piece of spring copper that connects the rotor to the cap frame.

If static occurs only when the radio is played loud, then the voice coil wires (the flexible ones that go from the cone to the frame) may be intermittent.

Static can also occur from internal arcing from any of the coupling or bypass capacitors. The IF transformers may have issues (Silver Mica Disease), but that is the last place to go.

Hope this helps.

Best Regards,

Mr Fixr

"Do Justly, love Mercy and walk humbly with your God"- Micah 6:8
"Let us begin to do good"- St. Francis

Best Regards, 

MrFixr55


Messages In This Thread
Philco model 49-900 - by tonto007 - 10-05-2021, 05:20 PM
RE: Philco model 49-900 - by GarySP - 10-05-2021, 06:01 PM
RE: Philco model 49-900 - by mikethedruid - 10-05-2021, 06:17 PM
RE: Philco model 49-900 - by falcon123 - 10-05-2021, 08:48 PM
RE: Philco model 49-900 - by MrFixr55 - 10-05-2021, 09:38 PM
RE: Philco model 49-900 - by OZ4 - 10-05-2021, 10:18 PM
RE: Philco model 49-900 - by MrFixr55 - 10-06-2021, 07:00 PM
RE: Philco model 49-900 - by tonto007 - 10-07-2021, 10:44 AM
RE: Philco model 49-900 - by RodB - 10-07-2021, 02:40 PM
RE: Philco model 49-900 - by Radioroslyn - 10-07-2021, 03:03 PM
RE: Philco model 49-900 - by tonto007 - 10-09-2021, 01:53 PM
RE: Philco model 49-900 - by Arran - 10-10-2021, 02:32 AM
RE: Philco model 49-900 - by tonto007 - 10-10-2021, 05:40 PM
RE: Philco model 49-900 - by David - 10-10-2021, 08:36 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Need to purchase some accessories for restoration of my Old Philco Radio
Hi Paulo, Welcome to the Philco Phorum. I can see why you want to find good reproduction parts. That is a bea...MrFixr55 — 11:10 PM
HiFi (Chifi) tube amp build - but my own design.
Tim, I have some bakelite sockets in my work shop that I can dig up. I believe quite a few are NOS. I will take photo...RodB — 10:03 PM
Philco 610B oscillator wiring
> The cathode as noted is wired directly to the ground side of the heater filament for that tube, not to the #17 and ...Radioroslyn — 08:12 PM
HiFi (Chifi) tube amp build - but my own design.
Tim; I noticed your post a little late, but I would take one of the junk sockets and try to break a chunk out of it wi...Arran — 08:07 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM

[-]
Who's Online
There are currently 1364 online users. [Complete List]
» 1 Member(s) | 1363 Guest(s)
Avatar

>