Early Electronic Television
Andrea KTE-5 Restoration
The Cabinet: This set has no cabinet. It has a wooden front panel, which is in excellent condition
The Chassis: The chassis has been painted with a grey metallic paint, which probably hides rust. The set was restored at some time in the past, using modern parts under the chassis. We will first get the set operating, then replace the paper capacitors with old style ones (which we will rebuild) and put the modern electrolytics in the original cans. Here is technical information on this set.
The set has a raster, though the CRT is very weak. A 5BP4 was installed rather than the original 5AP4. We have no spare 5AP4s, and will attempt to find a replacement.
The first problem is that the RF sensitivity is very low. An inspection of the tuner reveals that the RF input coil has the wrong tab connected to the chassis. Soldering the correct tab to the chassis brings the sensitivity up to normal.
After peaking the sound IF trimmer capacitors to 8.25 mHz, the sound now is normal. The video, however, looks distorted, with double images. In addition, the vertical (frame) sync is very unstable. Looking at the output of the sync separator tube (valve), there are two pulses for vertical sync, rather than one.
A check of the IF alignment shows that the 14.25 mHz adjacent channel sound traps have been mistuned. Readjusting them solves the double images and the sync problem.
Finally, someone attempted to compensate for the poor sync stability by changing some of the component values in the sync separator. I returned them to the original values, and the set now works well.
The 5AP4 is very weak. I have located a new one.