Airline Model 35WG308A No Picture

[RedDodge1968]

My Brother in law has an Airline console with record player, radio, and TV combination all in one cabinet. When he got it someone had knocked the end of picture tube off. The TV had, and has perfect audio, the sound is crisp and clear. He finally tracked down a replacement picture tube. We went through all of the tubes on the TV chassis checking each one, replacing weak, leaky, or shorted tubes. We carefully installed the 21MP4 picture tube.

Upon firing up the set all we can get is a faint horizontal line across the center of the screen, it is not affected by the brightness control, however by turning some of the other adjustments it will fade completely out. The audio quality is still perfect, we just cant get a picture.

Neither of us are TV guru's, so I was hoping someone may could point me in some direction, we have not received the schematic for the set yet.

[DaveWM]

horz line means no vertical deflection.

faint does not make sense as it should be bright as its not having to sweep the entire tube.

I would start with a check of the HV using an HV prob, would expect to be 15-18kv at the anode. If HV is good then you would need to trouble shoot the vertical.

Does it use a Tube for the B+ (like a 5u4) or doe it use diodes. Have you recapped it (filter or doubler if a doubler is used).

My guess is the power supply is at least working somewhat since the audio is working, but there maybe issues.

If the B+ is good and the HV is good, then I would look into vert tube and then caps. You should HEAR the vert running at the yoke, it makes a hum/buzz sound appox 60hrz.

checking the vert tube voltages would be in order, a scope is helpful.

when it comes to TV's you really need a schematic if there are problems.

low brighness could be a cut off problems on the CRT, checking pin voltages there is required. If cut off then I would check the video out tube and circuits.

could also be a screen or focus voltage issue.

[RedDodge1968]

I thought about checking the high voltage, but to be honest I really did not know what kind of voltage I was looking for, and know I don't know how I am going to take a reading that high?

We do have the high frequency noise you can hear coming from these circuits, or transformers, it changes as you move the different pots.

My brother in Law has replaced most all of the bypass capacitors, and has replaced all of the electrolytic caps.

The line seen is very faint, it is not bright, and turning the brightness control changes it none, but by moving some of the other pots you can cause it to fade completely out.

I appreciate your thoughts, I am going to head back over there after while, and check on some of this. Thank You!!

[RedDodge1968]

I have been kind of in suspect of some of the large wire would resistors, as I had to deal with these on My Admiral, these caused a loss of picture on my set, but the ones in this set do not display their value, and we have not received the schematic yet.

[DaveWM]

you need a HV prob to check. they are on EBAY a lot. Some folks just look for a large arc that can be drawn when the anode cap is disconnected and is close to the chassis, I don't recommend that as I prefer to use the correct tool to see what is going on.

IF the HV is bad and IF the vert is powered by the boost from the fly, then that may account for both the lack of brightness and deflection.

[ctc17]

Really needs all the capacitors changed except the disk caps. If you hear squealing the horz frequency could be way off most likely due to bad caps. Could be anything but that is the first place to start.
If this has any of those domino style caps in the horz circuit, replace them

[RedDodge1968]

OK, I am convinced we have high voltage, without a high voltage probe I don't know exactly how much, it is enough voltage that through the rubber insulation around the front of the picture tube you can maintain a 1/8" arc holding a screw driver against the rubber, and close to the chassis. The TV will still only emit a very faint line across the center of the screen.