A
Appreciate_It
This was for a high-shcool classmate, so I took special interest to
see that it is done properly.
Originally, the set was completely dead. Found out problem to be
blown Fusible 0.1-ohm Resistor and two Power Switching Transistors on
the Power Board (usual problem), as well as Blown HOT and a solder
crack at the Horizontal driver Xformer (again, usual problem).
Replace/clean/resolder all of above. Power up using Variac and 75W
bulb in 130V, checked HV in 2nd Anode using HV Probe and all that.
Everything worked fine with TV facing down and case open. After
putting the case back on, however, there was sound, but no raster.
The LED flashed at 1 second frequency.
After scratching our heads for a few minutes, we decided to open the
case again. We then found that the case was interfering with one
cable to the CRT-socket board, to the point that the socket board was
pulled to a slanting position (as opposed to being square to the CRT
neck). After we repositioned the cable and put the case back on,
everything worked - for a week... My conclusion was that either the
heater or the cathode pins were not making contact (Right???)
I got a call a few days later that the TV has lost the raster again,
but with sound and the flashing LED, just like when we found the
CRT-socket board was at an angled postion before. I am going to make
a house call in a few days. I would like to ask the group experts on
whether I am on the right track, or are there any other probable cause
for the said symptom?
Thanks,
Appreciate_It
see that it is done properly.
Originally, the set was completely dead. Found out problem to be
blown Fusible 0.1-ohm Resistor and two Power Switching Transistors on
the Power Board (usual problem), as well as Blown HOT and a solder
crack at the Horizontal driver Xformer (again, usual problem).
Replace/clean/resolder all of above. Power up using Variac and 75W
bulb in 130V, checked HV in 2nd Anode using HV Probe and all that.
Everything worked fine with TV facing down and case open. After
putting the case back on, however, there was sound, but no raster.
The LED flashed at 1 second frequency.
After scratching our heads for a few minutes, we decided to open the
case again. We then found that the case was interfering with one
cable to the CRT-socket board, to the point that the socket board was
pulled to a slanting position (as opposed to being square to the CRT
neck). After we repositioned the cable and put the case back on,
everything worked - for a week... My conclusion was that either the
heater or the cathode pins were not making contact (Right???)
I got a call a few days later that the TV has lost the raster again,
but with sound and the flashing LED, just like when we found the
CRT-socket board was at an angled postion before. I am going to make
a house call in a few days. I would like to ask the group experts on
whether I am on the right track, or are there any other probable cause
for the said symptom?
Thanks,
Appreciate_It
