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
#50

Just my two cents, but, from what I remember from working on these old analog TVs half a century ago, it looks like your horizontal hold and vertical hold are WAY out of adjustment. The horizontal hold accounts for the many narrow bands, and the vertical hold for the thicker rolling band. Adjust the vertical hold until the thick band stops rolling and you are left with just the narrow bands, then adjust the horizontal hold. As you do, you should see these many lines decrease, and decrease, until you have just one solid raster. Be aware, analog TV is no longer being broadcast. You will have to feed an appropriate signal into the set from an old VHS or DVD player which has an analog NTSB output. That will probably be 75 ohms, so you will need to get an adapter for 75 to 300 ohms, which was the standard input for the twinlead used back in the day. Also, without a signal to latch onto, you will have a very hard time getting a stable raster since the broadcast signal has a synch pulse used by the set to lock the frame scan. If you really want to do it right, I advise buying a vintage TV test pattern generator. They can be found on eBay.
[Image: https://i.ebayimg.com/images/g/BkQAAOSwN...-l1600.jpg]


Messages In This Thread
RE: Recapped My Predicta Tandem, I don't know what to do - by mikethedruid - 01-16-2022, 05:05 PM



Users browsing this thread: 13 Guest(s)
[-]
Recent Posts
The list of my radio & TV collection!
Hello Peter, Thank you for posting that !! Sincerely Richardradiorich — 09:40 AM
Eico 232 VTVM Schematic
It's a microwave antenna. ?;-p?. I substituted 1N4002s off the 6.3 vac winding for the 1.5 volt battery. Uniprobe is the...RodB — 05:50 PM
Eico 232 VTVM Schematic
Try BAMA for a schematic. Looks like a replacement power source for the D battery has been installed. The tube may be...Chas — 04:51 PM
Eico 232 VTVM Schematic
Is that a battery holder?morzh — 04:43 PM
Eico 232 VTVM Schematic
A friend gave me this Eico 232 VTVM and I'm having trouble locating the schematic for it. This one seems to be a later v...RodB — 04:17 PM
Var resistor id
Considering what it is in series with, I doubt there should be any power requirements. Of course, we should know wher...morzh — 03:23 PM
Var resistor id
Trim pot, about 1/2 watt part of focus divider. As stated 2k ohms. This appears to be a rusty chassis, resolder all ...Chas — 03:19 PM
Var resistor id
Its a Sylvania 400 oscilloscope. here is a clip of r-100. Would be nice to know the current required. Not listed in part...Martinj — 02:10 PM
The list of my radio & TV collection!
Thanks Richard. I hope you enjoy it. Here I have created an English section on the history of radio with videos in Engl...RadioSvit — 10:23 AM
The list of my radio & TV collection!
Hello RadioSvit, first all happy new year ! I will watch your new videos this week. Sincerely Richardradiorich — 09:19 AM

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

>