cameronflyer
05-31-2014, 03:00 PM
Hello all,
I wasn't going to put this set up at all because it its not a very complex, challenging or particularly interesting set. But! As with anything built or rebuilt by man things happen. I finished it up last night after letting it sit on the bench looking at me for a couple of months.
The reason it took so long was entirely my fault. When I got the set I figured it would be a fun afternoon project.All I needed to do was recap and check and replace a few resistors or so I thought. After replacing all the parts and powering it up I noticed no matter what I did I couldn't get full vertical sweep without fold-over at the bottom of the picture. I checked and rechecked all my work. Replaced parts I didn't think were bad just because they were in the circuit. Went over voltages and waveforms with a fine tooth comb. I couldn't find anything wrong so I put her back on the shelf in frustration. Over the weeks I would occasionally take her down and go over everything again, still finding nothing.
Well, last night I started on her again but this time I not only went through every trace wire and part to confirm they were all in the correct place, for the first time I went over every cap. value as well. About halfway through the checks I ran across an incorrect cap value on the grid of the 12BH7A vertical output tube. The schematic called for a .022uf and I had installed a .0022. When I went to the drawer labeled .022 I found a few caps with .0022uf in there. Obviously I put the wrong cap in that drawer at some point in the past. When I installed the correct cap and powered her up everything worked great after only a few minutes of alignment.
Sorry to make this tread so long. I only wanted to post it to prove a point. I have been working on televisions for a living for about 25 years now and I missed something as simple as a cap value. The moral of the story is this. If you are sure you have done everything right and the set still doesn't work look back at what you did, and you will usually find the problem.
I wasn't going to put this set up at all because it its not a very complex, challenging or particularly interesting set. But! As with anything built or rebuilt by man things happen. I finished it up last night after letting it sit on the bench looking at me for a couple of months.
The reason it took so long was entirely my fault. When I got the set I figured it would be a fun afternoon project.All I needed to do was recap and check and replace a few resistors or so I thought. After replacing all the parts and powering it up I noticed no matter what I did I couldn't get full vertical sweep without fold-over at the bottom of the picture. I checked and rechecked all my work. Replaced parts I didn't think were bad just because they were in the circuit. Went over voltages and waveforms with a fine tooth comb. I couldn't find anything wrong so I put her back on the shelf in frustration. Over the weeks I would occasionally take her down and go over everything again, still finding nothing.
Well, last night I started on her again but this time I not only went through every trace wire and part to confirm they were all in the correct place, for the first time I went over every cap. value as well. About halfway through the checks I ran across an incorrect cap value on the grid of the 12BH7A vertical output tube. The schematic called for a .022uf and I had installed a .0022. When I went to the drawer labeled .022 I found a few caps with .0022uf in there. Obviously I put the wrong cap in that drawer at some point in the past. When I installed the correct cap and powered her up everything worked great after only a few minutes of alignment.
Sorry to make this tread so long. I only wanted to post it to prove a point. I have been working on televisions for a living for about 25 years now and I missed something as simple as a cap value. The moral of the story is this. If you are sure you have done everything right and the set still doesn't work look back at what you did, and you will usually find the problem.