J
JURB6006
- Jan 1, 1970
- 0
Hi all;
This is a bit out of the ordinary. Has vertical sweep but only about ¼ of the
screen. The frequency is also way too high, about 300 Hz.
This set is at my house so it's a bit ackward to troubleshoot. So far, once I
saw the symptom I checked a bunch of caps to no avail and then decided to
change the jungle IC, still no good.
Now I got the scope out and find normal drive to the vertical output IC, so I
changed that, also with no results.
Strange thing is that I'm getting deja vu on this. It's as if I've seen it
before, and it may have even been an NAP direct view with a similar chassis to
the main board in the PTV 375. Does it ring a bell with anyone ? I'm trying to
save some time (and my back) because I have to hunch over to work on the thing.
I tried Repairworld using everything I can could think of, W1, 27W1, PTV 375,
the model number and even perused other NAP chassis' that have a similar
design. Nothing.
Now the strange part ( ! ) After the set is on awhile it starts working
intermittently, and it seems to depend on beam current. When the video goes
dark it collapses, when it gets bright it opens up and works, but only after
it's on for about an hour. (that's why I checked caps)
Even though this thing is a bit old, it still has sharp tubes and other than
dust was pretty clean. Indications are that it has never been serviced, yet it
doesn't even appear to need a coolant change. Heck, it doesn't even need the
customary resoldering !
I'm considering a PTS board for it, but the cost is high, what's more I really
don't want to part with the H deflection transformer for obvious reasons. Of
course PTS might just say to send the dud in first, I wouldn't blame them. Of
course at this point they might not even do these boards anymore. Doesn't
matter at this point, the board is only a last resort.
Thanx in advance.
JURB
This is a bit out of the ordinary. Has vertical sweep but only about ¼ of the
screen. The frequency is also way too high, about 300 Hz.
This set is at my house so it's a bit ackward to troubleshoot. So far, once I
saw the symptom I checked a bunch of caps to no avail and then decided to
change the jungle IC, still no good.
Now I got the scope out and find normal drive to the vertical output IC, so I
changed that, also with no results.
Strange thing is that I'm getting deja vu on this. It's as if I've seen it
before, and it may have even been an NAP direct view with a similar chassis to
the main board in the PTV 375. Does it ring a bell with anyone ? I'm trying to
save some time (and my back) because I have to hunch over to work on the thing.
I tried Repairworld using everything I can could think of, W1, 27W1, PTV 375,
the model number and even perused other NAP chassis' that have a similar
design. Nothing.
Now the strange part ( ! ) After the set is on awhile it starts working
intermittently, and it seems to depend on beam current. When the video goes
dark it collapses, when it gets bright it opens up and works, but only after
it's on for about an hour. (that's why I checked caps)
Even though this thing is a bit old, it still has sharp tubes and other than
dust was pretty clean. Indications are that it has never been serviced, yet it
doesn't even appear to need a coolant change. Heck, it doesn't even need the
customary resoldering !
I'm considering a PTS board for it, but the cost is high, what's more I really
don't want to part with the H deflection transformer for obvious reasons. Of
course PTS might just say to send the dud in first, I wouldn't blame them. Of
course at this point they might not even do these boards anymore. Doesn't
matter at this point, the board is only a last resort.
Thanx in advance.
JURB
