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 38-690 electronics restoration.
#97

Still some ails that plague it. One is this switch, the BC band secondary solders to the switch contact that is unreliable. No good way to reach it.

Then there's an open coil primary at the 2nd band, which I think I'll leave be as it is the police etc band, not much there anyway. Other bands I aligned.

Then the dial...am not sure as to it being exact same with internal ring, as in 37-116 deluxe, as then it means the inner ring is missing and someone riveted a piece of aluminum to the opposite of the stub that used to hold the ring and now he two are used to hold the dial which otherwise is good, but it slips and not held reliably.

Then there was this hum. Pretty pronounced. Right across the bass field coil I saw a pretty large ripple. I tried caps tono result. Then I started tacing it and traced to the power amp 6F6 input. That traced to the tuner output, the second audio 6N7, metal case. I realized the capacitor that is the output of it was hidden and I didn't restuff it. Fixed it, again to no result. So I cannibalized my 37-116 chassis with a glass 6N7G and....the hum went down a lot.
Then I looked at the second 37-116 chassis and it had a metal 6N7, same as I have, and after the change the hum was practically gone.
That was the tube!!!! The ripp!e on the scope also went way down.
The tube did test well - I tested all of them.

Well, at least some good news for today.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.


Messages In This Thread
Philco 38-690 electronics restoration. - by morzh - 04-12-2017, 08:19 PM
RE: Philco 38-690 electronics restoration. - by morzh - 11-26-2017, 09:47 PM



Users browsing this thread: 10 Guest(s)
[-]
Recent Posts
The speaker table error?
G  10-1/2"       65, 76, 87, 95 Push-Pull 45's 2766 0.7 550 3200 H   10-1/2"    77, 96 Push-Pull...morzh — 09:26 PM
A Marconi model 86
I have a Stromberg, one of the early ones, seems early 30s. This is what I call a back breaker. None of the early Philc...morzh — 08:28 PM
A Marconi model 86
A backbreaker.....PaulPaul Philco322 — 08:12 PM
A Marconi model 86
>>What a behemoth! A Juggernaut.morzh — 07:47 PM
Philco 70 antenna lead
I am not sure I understood about the coils and the mush. I looked an more than one coil in 20, 70, 90, 60, Zeniths and ...morzh — 07:46 PM
A Marconi model 86
:e_biggrin: What a behemoth!  I hope the final result is as much a quality sounding example!  Keep us posted on your pro...GarySP — 07:32 PM
A Marconi model 86
I should add that the double conversion may only be used on the shortwave bands, but I haven't looked at the schematic t...Arran — 07:27 PM
Philco 70 antenna lead
Yes, that wire will not pick up much interference as routed - the RF at that level won't be affected, and if you have st...radio1 — 07:26 PM
Philco model 60
I'm also a member of MARC. Did you attend the Vintage Electronics Expo in Waterford, MI last month? That's where I got...GarySP — 07:22 PM
A Marconi model 86
Dan Double conversion is using two IF converters instead of one. This improves the image response. morzh — 07:15 PM

[-]
Who's Online
There are currently no members online.

>