[Premium-Rx] HF-2050 VFO issues

[Paul]

Hi Gang,

 

How have you been. Paul Wende here
again into radio after a long hiatus.  I
still enjoy radios but have been busy with business and my son, house
projects etc.

 

Anyway, I just bought, yet another, HF-2050. This last one came from UVIC
science dept. and is damn near new! I couldn’t believe it when I opened the
box.  Must have been put in the rack and just sat there for years. It looks
like the warrantee stickers haven’t even been broken on the screws.

 

So, it has the usual heat problem but it also has a new problem that I have
not encountered and wonder if you have run into this before? When I first
powered it up, it ran fine for ½ hour or so, then the bottom of the freq.
display started to fade out
shut it off, turned it back on same thing, came
back on with the bottom half missing. I pulled the main front panel cable
and reseated it and that problem seems to be gone but the real problem is
the tuning VFO. It sometimes does nothing when turned. The frequency doesn’t
change. Then after a second or 5, it starts wildly changing and jumping all
over.  Sometimes it works 100%. I completely disassembled the optical
encoder and everything looks good. I am going to publish an article on this
procedure as I also fixed the horrendously stiff shaft. It’s actually pretty
simple if you are careful and take your time. 

 

So, I am thinking maybe supply ripple, a bad tantalum cap or ????  I
reseated all the socketed chips but haven’t really gone diggin much further.

 

Your thoughts? Has anyone seen this problem?

 

Thanks

 

Paul

VE7KHz