My Amplifone problems solved

I figured out both of my Amplifone problems last night that I wrote
about on Monday. I'm somewhat embarrassed by what happened, but perhaps
someone else will benefit from learning from my mistakes, so I'll
present the information here.

With the original HV transformer back in the original HV board #1, on
the suggestion by Joe, I probed around to see if the B+ was out of
whack. I hooked up my volt meter to the output of CR3, and saw a
fluctuating 7 - 22vdc. Hmmmmm... It was a far cry from the 180V I
expected. Then I hooked up my scope for a quick sanity check. Indeed,
I was getting a fluctuating 7 - 22vdc. The next step was to check and
see if the winding on the HV transformer had opened up. I removed it,
and indeed, found that there was no longer continuity between pins 4 and
8. Usually, this is around 2.3 ohms. I was about to chuck this in the
trash when I noticed that one of the transformer wires was no longer
connected to pin 4. Ta Da! I had merely a broken wire on my hands. I
soldered in back in to place, reinstalled the HV transformer, and
powered up the beast. It worked! Woo hoo! That's not the embarassing
part though. :-)

After getting this unit working, I decided to see if I had destroyed my
brand new tube or not. So I installed the new tube into my test
chassis. I powered everything up, and it didn't work. The tube
displayed the same symtoms as it did originally - i.e. washed out
picture, then the display turned all red, etc. And, the heater was
glowing way to bright! Defeated, I unhooked everything and decided to
put the tube back into its box and put it away for another rainy day.
As I was disassembling it, I noticed one of the long pins was BENT, and
it bent in such a way that it was now lined up to insert into a
different pin receptacle in the neck socket!!!! DOUGHT! I straightened
this pin, and tried again. This time, everything worked perfectly.

It shouldn't have taken me this long to figure this out, but at least in
the end I saw the problem and nothing was damaged. After this victory,
I installed the old red HV unit into board #2, and that board came to
life for the first time since I've owned it.

Now I have two working Amplifones.. woo hoo! I still have two more HV
units to work on, but I haven't even attempted to fix them yet. Perhaps
some time this weekend.

I hope someone else learns something useful from this experience.

Now I can install one Amplifone into Tempest, and the other into Star
Wars. These Amplifones just look so good!

Joel-
Received on Wed Nov 5 10:46:45 1997