[Boatanchors] The SB-610 Monitor Scope's trace

Sun, 1 Jun 2003 12:12:58 -0400

Hi Bill:

As an ex-Heathkit service technician I can say that the SB-610's simple
focusing circuit will never give you a perfect trace, but the controls most
certainly DO have an effect on the sharpness (I have two SB-610 scopes in my
shack). The fact that you say the controls don't affect the trace at all
seems telling.

First, be sure the mu-metal CRT shield is in place.

Next, the pots in the focus and brightness circuits are subject to change
and deterioration due to their high values and also working in the
high-voltage environment. Check them with an ohmmeter, but try cleaning the
wipers with a very small drop or two of DeOxit. Be sure to test the values
of the associated resistors in the high-voltage focus/brightness voltage
divider as well.

That's my stab at "DX troubleshooting."  Let me know how you make out. You
should be able to get a very good (not perfect) trace.

== Vy 73, AI2Q, Alex in Kennebunk, Maine
http://users.adelphia.net/~alexmm/ai2q.htm

 .-.-.

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Bill Pancake
Sent: Saturday, May 31, 2003 9:08 PM
To: [email protected]
Subject: [Boatanchors] Herathkit SB-610 Monitor Scope

Hello All...

I could really use some suggestions for a solution to a problem I'm having
with my Heathkit SB-610 monitor scope. I have just replaced the 3" CRT with
an NOS  3RP1A as the old one died of old age.  The new CRT functions just
fine and all front panel controls function just fine.

The issue is that the CRT's horizontal trace (with no signal input) is very
sharp & crisp on the left side of the tube and gets less sharp and somewhat
thicker n' fuzzier as it approaches the right side. No adjustment of the
intensity or focus controls on the front panel will correct the "fuzzy"
right side of the line trace. When monitoring SSB voice signals the display
appears normal.

Anybody got any ideas on how to make the CRT's trace sharp and even in
thickness all the way across the display ??? Thanks & 73, Bill K0JWP
([email protected]).

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