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

Recapped My Predicta Tandem, I don't know what to do
#38

Your B+ is good enough to have a raster. Both the horizontal and vertical oscillators are running. I haven't been reading too close. Do you have a Sams Photofact? Or something with waveform drawings? It should have voltages too. Also you will need a scope. It doesn't need to be anything special.

I see from your pics that the horiz osc looks to be running too fast. and the vertical waveform driving the yoke is distorted and or way too fast that's why the foldover and saggy picture. Most likely caps causing the distortion. Look for tired resistors too. Oh and apparently the tube sockets are fragile. They break it where they clamp the tube pins just from pulling the tubes out.

Again once you know the voltage here is good. I would start on the vertical deflection it doesn't depend on the tuner, IF, or the horiz section. It's pretty straight forward. It runs at only 30hz. It should deflect full screen all by itself.  Again double check the caps found there and make sure It is wired correctly. Look at the waveforms here and look to the vertical output tube for goodness. The sams will have test points to check with an oscilloscope. You will also need a tube tester or a known good output tube. It takes some watts to drive the yoke.

Adjusting the vert and horiz controls just speeds up or slows down the oscillators so they will lock to the incoming signal IF.  Look to see if the pots are dirty or dead.

Set the vert adjustment at half way and find the vertical oscillator coil and try to lock the picture in. Don't be afraid here.  The oscillators only need to be close enough to lock in. I would use a large mirror so you can see while you are behind the set twisting on things.  You should be able to see the rolling speeding up on not. If you can get the picture to stand sill but won't lock the sync-intergrader in not working. That's the next chapter. 

  Watch a bunch of tv repair videos and it will start to stick in your brain. There a ton of videos.

!!!!!!!!!!!!!!!!!!!RESISTANCE IS FUTILE!!!!!!!!!!!!!!!!!!!!!!  
                           /\/\/\/\/\/\/\/\/\
                                                     
                                 [Image: http://philcoradio.com/phorum/images/smi...on_eek.gif]  Chris


Messages In This Thread
RE: Recapped My Predicta Tandem, I don't know what to do - by OZ4 - 01-08-2022, 10:14 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
Philco newbie with P-1891-WA console questions
Hello jeff, Far as C8,C11 50ufd ,25volt ECE-A1EN470UB , 667-ECE-A1EN470UB far as C8,C11 make sure you use Bi-Polar/Non...radiorich — 09:46 PM
Philco newbie with P-1891-WA console questions
Thanks Radiorich! I ordered and received the capacitors you so kindly laid out part numbers for. I am unsure about C-8,C...Jeffcon — 04:05 PM
Rogers Majestic R-646
Hello Vlad. In general, in my opinion, restoring a wooden case, even in such a bad condition, is much more pleasant than...RadioSvit — 01:23 PM
Rogers Majestic R-646
Paul Philco322 Yes, you are right. Bot only this very terrible and dangerous method as on picture can solve this prob...Vlad95 — 12:18 PM
Rogers Majestic R-646
That's a drag. I had a set from a heavy smokering environment and the nicotine was just sponged up by the Bakelite case,...Paul Philco322 — 12:07 PM
Rogers Majestic R-646
Here's how I did a similar restoration in detail. But it was easier anyway. (these radios are much smaller and lighter) ...Vlad95 — 12:05 PM
Rogers Majestic R-646
Hi  MrFixr55 It is nice that the tuning capacitor is covered; it should be cleaner than the rest of the chassis. No...Vlad95 — 11:54 AM
Rogers Majestic R-646
Chassis looks pretty good. I have seen that type of cosmetic condition deemed acceptable by many, we all have our standa...Paul Philco322 — 11:53 AM
Rogers Majestic R-646
Hi Vlad, Definitely keep us posted on the progress. Your experience will help newcomers to this hobby. I hear y...MrFixr55 — 07:47 AM
Video Source for Predicta
Hi Matt, DVD and Blu-Ray players typically lack an RF connection. In Addition, Blu-Ray players are almost all "...MrFixr55 — 11:36 PM

[-]
Who's Online
There are currently 1210 online users. [Complete List]
» 2 Member(s) | 1208 Guest(s)
AvatarAvatar

>