# Help on a 465M

B

Jan 1, 1970
0
I recently bought a 465m for $50 for my son to play with. (I had an Eico when I was a kid.) The trace is not so good.I opened it up and found -3.0 VDC on a TP that is supposed to be -5VDC. The +32 and +5 are OK. Looking at the various articles on the web and talking to a couple of people, including Deane Kidd, I concluded that 1) I need a good manual for as little money as possible. 2) Some advice based on your experiences as to which can is probably bad. 3) I have the original instruction manual for a 564B. Is the instruction manual for the 465M just as comprehensive? Also I a little weary of really getting into it. I used to repair TV's when I was a kid, and got nailed one too many times, so a good manual is important. Any kind of advice, besides drop kicking it into the creek, would be appreciated. My son just got a 30 in 1 kit, sort of similar to the Allied Radio 100 in 1 kit I used to play with....but allot more IC minded...really cool stuff. I think it is important for him to see what happens to circuits over time...thats why I needed dual channels.. Thanks in advance Bill Brobeck D #### Dr. Anton Squeegee Jan 1, 1970 0 I recently bought a 465m for$50 for my son to play with. (I had an Eico
when I was a kid.) The trace is not so good.I opened it up and found -3.0
VDC on a TP that is supposed to be -5VDC. The +32 and +5 are OK. Looking at
the various articles on the web and talking to a couple of people, including
Deane Kidd, I concluded that

1) I need a good manual for as little money as possible.

Don't be afraid to invest -- and I use that term deliberately --
$50 or so for a good condition manual. The 465 and 475 series is some of the best hardware that Tektronix ever turned out. Manuals Plus has an operating/service manual for the 465M, in the form of a military tech manual reprint, for$55.00.

http://www.manualsplus.com/mpstore/product.asp?sku=75135&dept_id=1

HOWEVER -- Join, and check with, the gang on Yahoo's 'TekScopes'
mailing list before you buy. They may be able to point you to a .pdf
copy.

Could be anything, but electrolytic filter caps have been known to
degrade over time. The ironic part about owning a 'scope is that you
often need a working one to fix the bad one.
3) I have the original instruction manual for a 564B. Is the instruction
manual for the 465M just as comprehensive?

Very much so. The 465 and 475 series was made well before
Tektronix's manuals deteriorated into near-useless thicker-than-normal
pamphlets.
Also I a little weary of really getting into it. I used to repair TV's when
I was a kid, and got nailed one too many times, so a good manual is
important.

Troubleshooting test gear is not for the faint of heart. You would
also do well to join the Tekscopes mailing list off of Yahoo groups.
I've been a member for some time, and have gotten excellent advice for
my own stuff.

http://groups.yahoo.com/group/TekScopes/
Any kind of advice, besides drop kicking it into the creek...

Anyone who even hints that you should drop-kick any such
'classic' instrument anywhere is a good candidate for having the same
treatment delivered to their own derriere.

You've got a fine instrument there. Good luck with it.

D

#### Dave Platt

Jan 1, 1970
0
Bill Brobeck said:
I recently bought a 465m for $50 for my son to play with. (I had an Eico when I was a kid.) The trace is not so good.I opened it up and found -3.0 VDC on a TP that is supposed to be -5VDC. The +32 and +5 are OK. Looking at the various articles on the web and talking to a couple of people, including Deane Kidd, I concluded that 1) I need a good manual for as little money as possible. Definitely worth having. Check with http://www.aa4df.com/testeqpt.htm - the operating manual for the 465, and the service manual for the 465M are both available in electronic form (PDF scanned images of the paper originals, I assume).$9 if you FTP the manual, $12.85 if you want it on CD. 2) Some advice based on your experiences as to which can is probably bad. Well, it's probably the filter can for the +5 rail! The manual will make it quite clear which one it is. If I recall correctly, most of the main filter caps are all in one small area of the main PCB - right rear as you look at the scope from front/above, I think. 3) I have the original instruction manual for a 564B. Is the instruction manual for the 465M just as comprehensive? The service-and-operations manual for the 465 is very good indeed. I can't compare it to the 564B manual as I've never seen the latter. Any kind of advice, besides drop kicking it into the creek, would be appreciated. My son just got a 30 in 1 kit, sort of similar to the Allied Radio 100 in 1 kit I used to play with....but allot more IC minded...really cool stuff. I think it is important for him to see what happens to circuits over time...thats why I needed dual channels.. From what I have heard, the commonest problem with these 'scopes is that the filter capacitors for the DC supply rails simply fail due to old age - the water from the electrolyte diffuses out of the case, and the caps go high-ESR and cease to filter. I picked up a used-but-working 465 a couple of years ago for all of$25. It went belly-up about a year later, with the trace wobbling all
over the place and the controls pretty much dead. DVM testing showed
that one of the DC supplies had many volts of AC ripple on it... the

Unfortunately, the original filter capacitors for the 465 are no
longer being made, and the original supply of spares at Tek has run
out. So, you probably won't be able to find an exact replacement.

The good news is that you'll almost certainly be able to pooge in a
modern 'lytic, of equal or greater capacity and equal-or-higher WVDC
to their proximity to the CRT.

What I did was unsolder the existing cap can (+ and - tabs, and four
(?) mounting tabs around the perimeter) and remove it. I bought a
suitable replacement (somewhat smaller) at a local electronics store.
The pins on the replacement didn't line up with the thru-holes in the
using 16-gauge solid copper wire, threaded the ends of the wires
through the holes and then pulled them through (snaking the new can
down to within about an inch of the PC board), cut the excess wires
and soldered, and then glued the can to two of the adjacent original
capacitor cans using some electronics-grade silicone sealant. Although
the new can isn't actually fastened down to the PC board, the
combination of the leads, and the adhesive holds it firmly in place
without putting stress on anything.

The 465 fired right up, and it works fine now. Well worth the couple
of bucks, and the several hours it took to diagnose the problem and
repair it.

I've been advised that it's a good idea to power up scopes like this
occasionally, just to make sure that the electrolytic caps do not
de-form due to unuse.

W

#### W7TI

Jan 1, 1970
0
Don't be afraid to invest -- and I use that term deliberately --
\$50 or so for a good condition manual. The 465 and 475 series is some of
the best hardware that Tektronix ever turned out.

_________________________________________________________

So true. I used to be a production test tech on the 465/465B back in
the '70s.

Be aware though, that the 465/465B is a totally (and I mean totally)
different design and construction from the 465M. The 'M was a military
version which had essentially the same specs in terms of performance,
but otherwise had almost nothing in common. Different case, boards, cal
procedure, everything.

My all time fave is the 465B. Snatch one up if you find a well cared
for specimen. And when you open the case, look for my signature as
one out of 50 that were ever made (about 1,000 out of roughly 50,000
total production). At the time it was Tek's largest seller by far.

Great scopes, all.

W
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