[Fwd: Re: Anyone out there with some SB-610 experience?]

[Steve]

I received advice from several guys on the reflector mailing list and
hereby offer my thanks.

By way of update . . . the recurring theme through the responses I
received was to replace the capacitors in the 1430V power supply. The
thinking is that those capacitors are surely leaky after 30 years and
the extra load they place on the power transformer can damage the BLU /
YEL 600VAC secondary winding. Since I had a failure in that winding of
the power transformer to start with, it may be that those caps were
leaky fifteen years ago!

It seemed like good advice, so I will replace those three capacitors
with the hope that my new used-transformer will survive and the higher
voltage will make for a brighter trace on the screen.

I'll post the results to the reflector.

Again, thanks to the several of you who offered advice. I'd still be
knocking around in the dark without your help!

73,
Steve
K8JQ

-------- Original Message --------
Subject: Re: Anyone out there with some SB-610 experience?
Date: Mon, 28 Jul 2003 19:22:46 -0400
From: Steve <steveac at CHARTER.NET>
Reply-To: Steve <steveac at CHARTER.NET>
To: HEATH at LISTSERV.TEMPE.GOV
References: <20030728.132850.-543453.2.pmarkavage at juno.com>

Hi Pete and Larry and Jim,

Thanks guys. Here's the situation.

I bought and built an SB-610 in the early '70's. In the late '80's it
quit working and I found the power transformer's 600 volt secondary to
be open. So I put the unit aside with the intention of getting back to
it. So, fifteen years later, I'm getting back to it :)  I did some
trading recently to acquire another monitor scope that I could use for
parts and whose transformer was good.

I installed the working transformer in my unit and now I have a trace on
the screen.

First issue: If the unit's been turned off for a while and cools, when
it's turned on there's a trace. It isn't very bright, but it's a solid
line across the screen with the SWEEP FREQ set at full CCW. I know it's
been a while since I last saw the screen, but as best I remember from
years ago, the trace was bright and keying waveforms and voice patterns
were readily viewed in a room with normal lighting. Now, the room has to
be darkened a good bit to see the patterns. Why is the display so dim?

Second issue: After it's been on for about ten minutes, the trace
becomes choppy. By that I mean that the horizontal trace line has gaps
in it. With the sweep frequency at minimum (full CCW), the trace has
four or five gaps in it, the length of each gap is about a quarter of
one of the divisions on the face of the scope, the gaps are spaced about
two divisions apart and they move from right to left across the screen.
If I turn the sweep frequency toward max, the gaps synchronize and stay
still when the SWEEP FREQ control is at about 1 o'clock. Any idea what
causes those gaps?

Thanks.

Steve
K8JQ

Peter A Markavage wrote:
> Why wouldn't you want to share the advice back and forth here on the
> list. Maybe others could benefit from the discussion. Asking questions
> here, and then asking for responses off-list are somewhat
> counter-productive to other members of the group.
> Pete, wa2cwa
>
> On Mon, 28 Jul 2003 12:41:29 -0400 Steve <steveac at CHARTER.NET> writes:
>
>>I recently got an SB-610 monitor scope working . . . or almost
>>working.
>>Anyone out there who is familiar with the circuitry and would be
>>wiling
>>to give me some advice?
>>
>>Please email me off list.
>>
>>Thanks.
>>
>>Steve
>>K8JQ
>>
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