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

37-620 BC Reception Issue
#1

I have revived this 37-620 radio which was a basket case. This is my first radio. I receive BC signals but they are tough to lock, and I receive loud squelching just before I get the signal. Once I get the signal and get beyond the loud squelching, I have to turn down the volume or else it becomes saturated.

I have a single ended antenna connected to Input 1 with 2 connected to ground, it's length is apprx. 12 feet. It is supposed to be some sort of dual antenna with the center tap of the RF transformer grounded.(Input 3)

My thought is that the alignment might be the cause of this issue.

Any thoughts?

Thanks
#2

A leaking capacitor may cause it to loose a station after it is "locked in"
#3

It locks in, but will saturate if volume is turned up. Also is very sensitive to adjustments. Before station is obtained squelching is heard that you would normally would not get.

I'm thinking something may be slightly out in the oscillator circuit or the tuning capacitor. Not sure what symptoms would be seen with dirty tuning capacitor, I don't believe what I'm experiencing falls into that category.

Thanks
#4

Has it been aligned?
#5

Are all the tube shields in place? If not, you can easily get IF feedback which would cause this problem.
#6

Hi
Like Brenda said missing tube shields especially the first AF or the IF tubes. Also the cap in the agc curcuit or the cap in the IF tube screen grid bypass also the second filter cap or any of the other filter caps. In other words change out all caps. There are several caps that can cause your problem. Icon_biggrin My two cents
Joe

Joe Bratcher near Louisville, KY
#7

Brenda,

That's a good idea on the shields. I will try to find some for this model. Another question on this model is the antenna setup, is it better to try a loop antenna like the one Philco suggests, or just use a single ended one?

Thanks
#8

Single ended random wires work well with these sets.




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Zenith H725
David - I think I understand but what units are you discussing (Low of 1.7, high of 3.9)? Budget constraints for Ham ...EdHolland — 01:43 PM
My Philco 37-116 Restore
You're doing great. I wish I could be more involved, but my mind is right now preoccupied with the reason I am here in ...morzh — 12:21 PM
My Philco 37-116 Restore
Hope you guys are still with me. I have moved on to the alignment. I completed the IF alignment which was pretty muc...dconant — 10:47 AM
My Philco 37-116 Restore
Hello MrFixr55, Thank you for taking the time to explain. I measured 50 volts where you say. Today the 370 volts at ...dconant — 12:51 PM
462ron
Oh that sucks. It’s something easily overlooked. Hopefully it’s nothing more than a resistor! Ron462ron — 08:08 AM
Philco 46-480 Electronic Restoration
Just confirmed that you are correct. It’s the function generator. I connected the signal output probe to one of the inpu...jrblasde — 07:52 AM
Philco 46-480 Electronic Restoration
Ouch, you may be right. Yes, it is solid state. It’s the signal output of my oscilloscope. May be time to crack that ...jrblasde — 07:27 AM
462ron
If you didn’t put a DC blocking cap between the signal generator probe and the plate of the 1st IF it’s possible you ble...462ron — 07:07 AM
My Philco 37-116 Restore
Hi DConnant, The reason why C127 is isolated from ground is because sets of this vintage did not have the center tap...MrFixr55 — 01:07 AM
Philco 46-480 Electronic Restoration
The shield is on the 6H6. It was, in fact, a missing jumper to connect the main chassis ground to the RF chassis grou...jrblasde — 10:58 PM

[-]
Who's Online
There are currently 1021 online users. [Complete List]
» 1 Member(s) | 1020 Guest(s)
Avatar

>