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

37-660 Alignment Issue
#1

Well I've rewound the OT and it works fine. Began the alignment and all was going fine until the last SW tuning range 2 (2.3-7.4 mc). The first part of this stage you peak at 7 mc by adjusting the oscillator (30B)(no problem) and then you are to go to 2.35mc (closing the tuning cap plates) and peak there (30C) where I don't hear the sig gen signal.

If I set the sig gen to 6 mc the radio dial has to be set to about 6.65 mc to hear the tone (this is after peaking at 7 mc). To me it seems like it is short on capacitance. I note that across 30C (the 2.5 mc osc trim) there is what appears to be a large mica. According to the schematic this is 30x and is a 1150 uufd (I didn't change this one). The parts list does not say it is mica whereas it does state other small ones as mica. I am wondering if this cap might not be mica and could be causing my problem? Looking to you experts for help and suggestions.

http://www.nostalgiaair.org/PagesByModel...013220.pdf
#2

Hello, Marv: The best way to align is to connect a volt meter to the voice coil leads of your speaker and use min sig gen amplitude when adjusting your set.

This prevents your AVC circuit from interfering with your alignment.
#3

If I had to guess (and I do) Icon_wtf you are on the wrong peak. ie if the LO is to be at 6.53MHz when you tune 7Mhz, you have it peaked at 7.47 Mhz on the LO

turn the signal generator level down, and try to find a peak at 7MHz with the trimmer turned in tighter.

I would also assume the 1150 pF cap would be paper, you could try putting 2 .0022uF caps in series (1100pF) and see if the situation improves.

John
Las Vegas, NV USA
#4

Still have problem on range 2. Changed 1150pfd cap, no difference. Close inspection of coils noted that one lead of RF range 2 primary broke off wafer switch. (Probably happend when replacing caps deep within). Soldered lead back on to D3, still cannot align this range correctly.

Before I remove the RF section from chassis again to check this coil closer can someone please confirm that when the radio range lever is in range 2 I should read 12 ohms of the primary between D3 and D6 of the wafer. I read open. Getting to these coils is nearly impossible.

marv




Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco 91 code 221
Chassis grounds thru rivets is another good place to look. Oh and the stator screws on the tuning cap where the leads at...Radioroslyn — 08:11 AM
Philco 91 code 221
Dirty tube pins and socket, cold solder joint, stray tiny strand of wire, clean the entire area around the oscillator tu...RodB — 08:43 PM
Philco 91 code 221
I have been restoring one of these sets and switched it on yesterday. It didn't exactly spring into life, but after a co...Philconut — 08:26 PM
Philco 50-925 antenna connections
That's super. Glad to hear you figured it out. Paul.Paul Philco322 — 11:11 AM
Philco 50-925 antenna connections
Hello Keith, great news !! Sincerely Richardradiorich — 02:14 AM
Philco 50-925 antenna connections
Finally, got the antenna fixed (repaired some broken wires) and have the radio playing. I've got four different schemat...keith49vj3 — 09:38 PM
1949 Motorola 5A9M
Bob, Nice radio.  I’ve not seen one before.  Keep us updated!Joe Rossi — 07:56 PM
Phioco 90 Power Transformer Wire Colors
Thanks for adding that information.klondike98 — 06:09 PM
Phioco 90 Power Transformer Wire Colors
Although I have used this site as a resource for a number of years this is my first post.   I am restoring a Model 90 si...vincer — 05:02 PM
My collection presentation
There is a complete instruction how to solve your problem. One piece of advice - be careful with the low-voltage capacit...Vlad95 — 09:32 AM

[-]
Who's Online
There are currently 730 online users. [Complete List]
» 1 Member(s) | 729 Guest(s)
Avatar

>