Recapped My Predicta Tandem, I don't know what to do
Posts: 811
Threads: 43
Joined: Dec 2008
City: Chicago, IL
Two of the wires are for the AC tube filament supply.
Sounds like your horizontal frequency is way off. The frequency is determined by one of the couplates near the 6CG7 tube. There is also a coil with a mica cap in parallel that should be set to resonate at 15,750 Hz to help the oscillator stay in tune.
When you are feeding a signal the AFC circuit is trying to get the frequency right. Predictas tend to freak out like in you photo when the horizontal get too far off frequency.
Have you tried adjusting the slug in that horizontal coil? The frequency range control plays a part here too.
You should go through the horizontal setup procedure outlined in the service info.
(This post was last modified: 01-05-2022, 09:33 PM by Bob Andersen.)
Messages In This Thread
RE: Recapped My Predicta Tandem, I don't know what to do - by Bob Andersen - 01-05-2022, 09:33 PM
Users browsing this thread: 3 Guest(s)
|
|
Recent Posts
|
|
Philco 610B oscillator wiring
|
| Thanks for the replies. It's not the really the hum that I am after. Just trying to understand why only the shortwave ba...Tubester — 04:01 PM |
|
Restoring Philco 96
|
| 70 and 90 are Superhets, but at least the 2x45 model of 90 uses the Plate detector (and so does 70).
Also the Atwaters,...morzh — 03:28 PM |
|
Restoring Philco 96
|
| Morzh, Prayers for your mom. I am sure that there was enough pain living through the Holocaust as a child. I pray dail...MrFixr55 — 02:19 PM |
|
Philco 610B oscillator wiring
|
| Hi Dan,
Divide and conquer. First off trry to differentiate between 60Hz and 120 Hz hum. 120 Hz hum has a higher pit...MrFixr55 — 01:49 PM |
|
Restoring Philco 96
|
| Yes, other than takin a toll on your back, they are undeed way more repair friendly than many other Philcos.
To me, som...morzh — 01:04 PM |
|
Philco 610B oscillator wiring
|
| If the wires look like they were this way from the factory (very neat and very dull soldering joints), I'd leave them be...morzh — 12:58 PM |
|
My Philco 37-116 Restore
|
| I managed to open up the Expander Unit and replace the grid cap wires. Tested the connections found they looked good and...dconant — 12:19 PM |
|
610B Oscillator Questions
|
|
I've included a picture of the 'actual' schematic I created. I double checked several times and it appears to be accur...Tubester — 09:26 AM |
|
First Radio restoration
|
| Hi, welcome. I did a 40-130 a few years ago. I was very surprised at how well it performed. Just take care with that sp...Stan the Man — 07:20 AM |
|
Restoring Philco 96
|
| Situations of the like are not pleasant. Life is inevitable. Best of luck to you.
I have two 76 chassis, in different ...Stan the Man — 07:12 AM |
|
Who's Online
|
There are currently 1863 online users. [Complete List]
» 1 Member(s) | 1862 Guest(s)
|
|
|
|
 
|
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
