I figured out how to get to the broken parts and here are some pictures:
/g/TekScopes/album?id=270912It turns out that the front part of the drum cam was indeed glued to the drum body. I took a razor knife and worked it around that seam and the front hub popped right off. As you can see, the two sections inside that comprise the drive dogs and the hub were broken. I suspect a hard hit to the shaft with the gray knob removed but can't say for sure.
Jim - I presume these are the "dogs" you referred to?
Raymond - was this the part to which you were referring when you mentioned the "glue method"?
In any case, a bit if glue and this should be back together and working once again. If the tunnel diode I ordered works (I should get it in a few days), I may have a fully-functioning 7B53N.
Thanks,
Barry - N4BUQ
----- Original Message -----
From: "Raymond Domp Frank" <hewpatek@...>
To: "tekscopes" <[email protected]>
Sent: Saturday, December 18, 2021 1:10:59 PM
Subject: Re: [TekScopes] Internal Drive Mechanism for 7B53N (et., al.) Sweep Speed Cam
On Fri, Dec 17, 2021 at 10:44 PM, Jim Adney wrote:
For the original poster: If the front knob does not turn the B drum, does it
turn the 1/8" B drum's shaft? If it does, but the B shaft does not turn the B
drum, then the drive dog has either shattered (most likely) or come loose from
the shaft.
This all looks very much like a rather frequent problem with 465- and
475-scopes, which have similar construction. A lot has been written about this
on this Group, including the tricky - but successful for all who tried, AFAIK -
glue method that I suggested. Look around in the Group's messages; I have no
pointer nor the time currently to look them up, unfortunately.
Raymond
