Hello..my first TV

[old_tv_nut]

Originally Posted by Donj

I'm not thinking so..... OOPS. Just did a bit more reading and found this.." A potentiometer (contrast) control, permits this voltage to be changed on v2, v3, and v4 so as to vary thegain of the video 1-f amplifier"

So, I presume you're going to turn it and see (or hear) what happens

[Donj]

Turned on the beast and was greeted with an inch wide horizontal bar????? Maybe all my contact cleaning wasn't sufficient. I think I'm going to bed.

[Donj]

OK, Depression has passed ... After removing chassis and putting it on the stand I found absolutely nothing that I felt might have caused this minor setback. Hooked all back up and same horizontal bar across the screen. Messed with the 12 pin plug with no positive results. Then I noticed that one of the two LV rectifiers (5R4) on the PS chassis was glowing very dimly filament-wise. Removed it and reamed out the socket, bright filament and a full screen raster!!
Spent the day on the remaining sockets just to avoid further poor connection scenarios down the road.

Old Nut.. messed with the contrast control as per your suggestion, with no real noticeable video or audio effects...screen darkens up as contrast is increased, that's about all.
I was running the tuner through its paces and I found one position almost between chs 8&10 where I actually got some real off-air audio. Fine tuning had a major effect on volume of the noise. No real effect on the raster however. As I said, the contrast control really did not have an effect either.
I suppose that I should pull the tuner and give the switches a major going over in case they are suffering from this Gawd awful problem that every other connection point in this set seems to have.
Has anyone else ever seen a set suffering from this malady?

[Donj]

Some progress has been made.. With a VCR connected, my first thought was that I was getting no input signal response. However, I did detect an audio output with the set's volume set at max. Very low, but there. Since there was audio I started to look for video by playing with the various controls and finally found it somewhat. It seem as though with the brightness and contrast both set to minimum there is a viewable signal. Not great, but viewable.
Since it is there, what do you think I should be doing next?
I am going to check over components in the audio section, but don't expect to find much and as far as the video goes it seems as though every thing is way too bright. There is nothing I can adjust to obtain a black.
Now that I have an input source I will attempt to record a test pattern.
Can I test voltages with the CRT disconnected? It is still fastened within the cabinet and I really do not have room for it on the bench.
Also wondering if this is more likely component or alignment issues.

[Notimetolooz]

Originally Posted by Donj

Can I test voltages with the CRT disconnected? It is still fastened within the cabinet and I really do not have room for it on the bench.

You need the connections to the yoke. You can remove it from the CRT neck.
If there is a ion trap that will have to be removed first, but mark the position so that you can put it back on later in the same spot and orientation. Make sure that HV anode lead is well insulated by putting the end into a glass bottle or the like. There is very little current flow to the connections at the CRT base socket except for the filament. BTW, it this set has series string filament connection you will have to substitute something for the CRT filament.
You should check the voltages on the CRT socket anyway, it may indicate something.
EDIT: Just looked up the dats on the CRT, it doesn't use an ion trap, but it does use a focus coil. What I said about the ion trap applies to the focus coil. You will have to have the focus coil connected as well as the yoke.

[Donj]

Back to work. As per advice I'm measuring all that is measurable on this set. All coils ohm out as per the schematic. Resistors as well with some exceptions. These are pretty much all the 1 watt resistors, and seem to have a molded sort of body. They are all measuring extremely low. Below is an example. Shows as 47K on the schematic and that's what the colour code says... Measures out at 561 ohms. I'm used to seeing old resistors measuring high, but this set's seem to be doing just the opposite. Just the molded body ones.
Anybody seen this?