The Fisher 440-T FM Receiver
Posts: 1,114
Threads: 14
Joined: Feb 2013
City: Irvington, NY
Yes, it appears that the problem is that the transistor is not conducting enough to fully turn on the LED. Don't worry about grounding the MPX connection. You are only doing what the transistor should do and it will not cause any damage.
The spark is caused by the charged 100 uF cap being discharged to ground. You can put the 68 ohm resistor in series with the cliplead to limit the spark.
How much does the voltage at the collector change when receiving stereo? It should go from about 24 to almost zero, so if it is not then either the transistor is bad or it is not getting enough drive from the MPX circuit.
Messages In This Thread
RE: The Fisher 440-T FM Receiver - by Mondial - 03-13-2014, 08:05 PM
Users browsing this thread: 6 Guest(s)
|
|
Recent Posts
|
|
6TPZ and 5TPO Radio Help
|
| I am not a specialist in car radios.
I suspect they might use vibrators to convert 12V to acceptable tube voltages, so ...morzh — 01:58 PM |
|
6TPZ and 5TPO Radio Help
|
| Welcome to the Phorum, R3Sons! I have very limited experience with car radios other than installing custom radios back ...GarySP — 01:08 PM |
|
462ron
|
| OK, I need to rename this thread to say..Eico 368 TV/FM Sweep Generator instead of the current title..Heathkit Sweep Gen...462ron — 12:49 PM |
|
6TPZ and 5TPO Radio Help
|
| Hello, I have a Philco (Ford) 6TPZ and a 5TPO radio. I replaced the electrolytic capacitors in both. I have the SAMS m...R3Sons — 12:29 PM |
|
The list of my radio & TV collection!
|
| Hello Peter,
Thank you for posting that !!
Sincerely Richardradiorich — 09:40 AM |
|
Eico 232 VTVM Schematic
|
| It's a microwave antenna. ?;-p?. I substituted 1N4002s off the 6.3 vac winding for the 1.5 volt battery. Uniprobe is the...RodB — 05:50 PM |
|
Eico 232 VTVM Schematic
|
| Try BAMA for a schematic.
Looks like a replacement power source for the D battery has been installed. The tube may be...Chas — 04:51 PM |
|
Eico 232 VTVM Schematic
|
| Is that a battery holder?morzh — 04:43 PM |
|
Eico 232 VTVM Schematic
|
| A friend gave me this Eico 232 VTVM and I'm having trouble locating the schematic for it. This one seems to be a later v...RodB — 04:17 PM |
|
Var resistor id
|
| Considering what it is in series with, I doubt there should be any power requirements. Of course, we should
know wher...morzh — 03:23 PM |
|
Who's Online
|
There are currently 6503 online users. [Complete List]
» 2 Member(s) | 6501 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
