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
91H Code 126 Restore
Just to make it more confusing here is another model 91 schematic that doesn't show parts with dotted lines in that spot...Arran — 10:37 PM
Atwater-Kent 84, restoration.
The wires were desoldered from the can, and the capacitors checked. All checked at 0.102 uF, which is correct. So the c...morzh — 09:41 PM
An attempt to remove the Field Coil from a G speaker
Arran Yours probably then the H speaker, same as mine.morzh — 08:39 PM
An attempt to remove the Field Coil from a G speaker
Mike; I would like to have a look at the speaker in my model 96, but the set is packed into a corner in the basement. ...Arran — 08:04 PM
91H Code 126 Restore
Thanks Arran, I'm convinced the power cord is good but have a nice repro plug for it. Would it be prudent to add a fus...RealRider — 07:28 PM
91H Code 126 Restore
As I was studying this schematic I was wondering what does this dotted line means?  I haven't traced it out yet. An o...RealRider — 07:22 PM
91H Code 126 Restore
When it comes to the cloth covered power cords, if they are not frayed, and are flexible, and if I can bend one without ...Arran — 06:21 PM
An attempt to remove the Field Coil from a G speaker
Could be. The central cylinder is OK, but the sides are...well. What's done is done. I wonder if some standard bobbine w...morzh — 06:02 PM
An attempt to remove the Field Coil from a G speaker
Mike; As I was saying it doesn't look like they used much of a bobbin for the field coil, not like a Magnavox one wou...Arran — 05:49 PM
Atwater-Kent 84, restoration.
This AK84 was bought, I think, last fall. For a whopping $100. It has been, according to the seller, restored. As I go ...morzh — 05:48 PM

[-]
Who's Online
There are currently 6227 online users. [Complete List]
» 1 Member(s) | 6226 Guest(s)
Avatar

>