Recapped My Predicta Tandem, I don't know what to do
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
Posts: 797
Threads: 42
Joined: Dec 2008
City: Chicago, IL
Did you recap the board inside the CRT housing?
Your raster isn't filling the screen vertically which is not going to be caused by any issues with the video. Do the vertical size and linearity controls respond? Can you get the raster to fill the screen? Have you checked the power supply voltages?
(This post was last modified: 01-03-2022, 05:28 PM by Bob Andersen.)
Posts: 1,130
Threads: 79
Joined: Jan 2014
City: Annapolis, IL
I’m seeing both vertical and video problems. Make sure you put the correct value caps in. +1 on what Bob said on the linearly and height controls. Since you have good sound, that pretty much rules out tuner and IF. Check your video detector diode. Horizontal looks good and i don’t see sync issues. Look from your video detector to your output. Did you check the picture tube? Remember, this may use 2.5v NOT 6v! Don’t blow your filament!! You might post a pic of a video also. Hope this helps some. Oh, some audio output tube circuits are used as a voltage divider, so a problem there can affect other parts of the set.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
Posts: 797
Threads: 42
Joined: Dec 2008
City: Chicago, IL
Looks like the horizontal oscillator is off frequency. You also missed a couple caps. The yellow paper cap in the video amp and a white ceramic under the chassis in the lower left corner (.22 200v)
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
I thought that white one, was the safety cap or what ever it was called? lt doesn't effect the operation it was for safety right? I will replace it to though, I think it wasn't on the list.
Also I will replace the video Amp capacitor I missed tomorrow.
Whats the best way to trouble shoot the horizontal oscillator circuit?
(This post was last modified: 01-04-2022, 09:18 PM by apERNA1985.)
Posts: 15,691
Threads: 551
Joined: Oct 2011
City: Jackson, NJ
The black electrolytic PHILCO large cap on the left? In the second photo? Rebuilt?
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
Yes I restuffed it. You might be able to see the electrical tape holding it together.
Also I had the right value for the white cap and replaced it. I also took out the one in the video board, I don't have it. But I'll go to the store tomorrow.
On a side note, I hooked them up to my Heathkit C3 Condensor Checker and both didn't leak at 378v. I found out at 450 it only puts out about 378v.
Other than the big multi section caps most of the capacitors tested good in this set.
Posts: 1,130
Threads: 79
Joined: Jan 2014
City: Annapolis, IL
Did you rebuild C3 the can? There’s a 220mf cap on the cathode of the vert output tube. If it’s bad that will reduce your sweep.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44
Posts: 1,130
Threads: 79
Joined: Jan 2014
City: Annapolis, IL
In the 2nd pic, looks like an electrolytic under the newer black cap. Maybe this is the one Mike or Bob was talking about, but could be a problem if it’s not replaced. I also noted from the schematic the audio is not used as a voltage divider.
If I could find the place called "Somewhere", I could find "Anything"
Tim
Jesus cried out and said, "Whoever believes in me , believes not in me but in him who sent me" John 12:44
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
Ok the black cap I restuffed was C1, I didn't restuff C3 I just put modern black caps under the chassis they are next to C1 you'll see 2 larger ones and 1 very small cap. They're all tied together on the negative, the negative is tied to the ground lug of the original C3 cap, then the leads are soldered to the new caps.
Posts: 797
Threads: 42
Joined: Dec 2008
City: Chicago, IL
It's not called a safety cap because it makes the set safe. It's called that because it will fail in a safe way. Regardless, that's not the across the line (safety) cap. That would be C60 - the 0.1uF cap shown next to the power switch on the schematic. It should be replaced by an X2 type capacitor.
The cap I was referring to is C61.
Have you tried adjusting the horizontal hold and range? You'll need to put a small flat bladed screwdriver down the hollow horiz. nhold shaft for the range.
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
Yes, I adjusted all 3 of the pots inside the controls, along with the one in the back by the antenna connection to get the best possible picture.
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
Posts: 60
Threads: 7
Joined: Feb 2018
City: paramus, nj
So I was playing with the adjustments a little more and the picture got slightly better then all the sudden went completely white. I started to play with the tuner and the TV showed no reaction. I swapped the tubes on the tuner, and even unplugged the rca lead it had no effect at all. So I slid back the boot on the plug for the tuner, I think I lost a cap somewhere because now I have no voltage on the white wire. Here is what I found. I wasn't able to check the black wire in the center but from the diagram it looks like it's just power for the dial lamp and that is nice and bright.
Orange 207vDc
White 0 volts ac and dc
Green 0 volts DC 98 Volts Ac
Red 0 volts DC 90Volts Ac
I thought they should all be DC voltages am I wrong?
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
Jackson 715 not working
|
Mrfixr55, its working now. I cleaned the switches and sockets with spray cleaner. Thanks for helping on this one.daveone23 — 06:26 PM |
Jackson 715 not working
|
Now that you posted the schematic, I don't know why that Sprague electrolytic cap is across the meter, as it is not indi...MrFixr55 — 05:51 PM |
HiFi (Chifi) tube amp build - but my own design.
|
What may be lacking in the PP Tube amps may be the 2nd harmonics, which some, especially RCA back in the day called &quo...MrFixr55 — 05:32 PM |
Jackson 715 not working
|
Usually in an emission tester, the tube under test is measured as if it were a diode. So, some testers connect all the g...RodB — 04:17 PM |
Restoring Philco 37-604C
|
Yep. F5 is green, D5 is Red.
Red is Bad.
Green is Clean.morzh — 01:30 PM |
Jackson 715 not working
|
I did start to do that but I stalled out because I could not figure out how the grid and plate get voltage. In this diag...daveone23 — 11:52 AM |
Restoring Philco 37-604C
|
(Insert Homer Simpson "DOPF" Here.)
When all fails, look at the can. Took the Ron Ramirez advice, red Caig D...MrFixr55 — 09:23 AM |
Philco 91 Speaker Replacement
|
From your text I am not sure if you intend to use the existing speaker with a resistor instead of the field coil.
It wo...morzh — 08:44 AM |
Philco 91 Speaker Replacement
|
My field coil is bad. I am still hoping to find an original, but if I can't I will go with a fitting Philco speaker, 125...dconant — 08:34 AM |
Philco 91 Speaker Replacement
|
As Rod said, it is OK to use a fitting speaker, and then look for an original one.
If you buy a Hammond 125 output tr...morzh — 08:15 AM |
Who's Online
|
There are currently 3982 online users. [Complete List] » 1 Member(s) | 3981 Guest(s)
|
|
|
|