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: 1 Guest(s)
|
|
Recent Posts
|
|
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 |
|
Zenith H725
|
| Ed;
One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to ...Arran — 11:42 PM |
|
Zenith H725
|
| I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. Th...EdHolland — 08:39 PM |
|
Zenith H725
|
| The PSU filter cap arrived today (thank you USPS!) so I will work on that later.
Meanwhile, I have the dial, speaker...EdHolland — 06:42 PM |
|
Philco 610B oscillator wiring
|
| Thanks Terry. After checking my notes I think I recorded about -10v at the 6A7 G4/control grid. The screen grid (G3 &...Tubester — 05:59 PM |
|
Who's Online
|
There are currently 1546 online users. [Complete List]
» 1 Member(s) | 1545 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
