It's one of those things you may only use once every two years but damn
does it make it easy.
I have a 1503 as well as a 1502 and I had to find where in my attic the
Romex was tapped into. I was able to locate the junction box which was
hidden two within less then one foot. That paid for it many times over.
The other one were at paid for itself was a broken wire restoring a r390a
HF receiver I was able to locate the brake in a wire in the middle of a
wiring harness to within an inch.
toggle quoted message
Show quoted text
On Fri, Jun 29, 2018, 9:13 AM Richard Solomon <dickw1ksz@...> wrote:
I picked up a working 1502 a few years
ago on that auction site.
The batteries were shot, but I found a
paper on using a resistor and a big cap
to fool it into thinking it had batteries.
I think I have used if less than 5 times
over the years, but for the price it was
a nice addition to the test equipment
pile.
It didn't hurt that I had an original manual
for it.
73, Dick, W1KSZ
On Fri, Jun 29, 2018 at 4:11 AM, Tom Gardner <tggzzz@...> wrote:
I really like 1502 (not a, b, 1503 etc), and have some I ought to sell.
There are two principal weaknesses other than the usual PSU caps:
* the tunnel diode is relatively fragile, and can be destroyed by a DC
voltage
on the cable or even a static charge in the cable - hence the special
shorting BNC connector. Having aid that, all 5 that I have seen are
intact
* the battery pack must be present before it will switch on: the PSU
detects
missing and uncharged batteries. All 5 that I have seen have had
faulty
batteries. There are ways of faking a battery, or they can be replaced
by
new sub-C NiCds or NiMH. With NiMH be very careful with "Chinese
capacity
specifications" and the trickle charging current.
On 29/06/18 04:09, Pete Lancashire wrote:
Yeah if you need the short distance performance the 1502 is the only way
to
go. The newer models which have LCD redoubt if the LCD has not gone bad
now
it will. And the unfortunate part is the LCD was custom.
keep your eyes open a lot of sellers don't know what they have but like
another member said make sure the tunnel diode is good.
A few people have looked at the ex Soviet tunnel diodes but as far as I
know no one has found a substitute.
To me sounds like a perfect project to use a modern pulsar there are an
awful lot of 1502s out there.
On Thu, Jun 28, 2018, 1:00 PM Harvey White <madyn@...>
wrote:
On Thu, 28 Jun 2018 11:02:57 -0700, you wrote:
As Stefan said, how fast a step pulse you need and how much scope
bandwidth you need both depend on how much resolution you need. Do you
happen to have sampling plug-in set for your 7000 series mainframes?
If
not, how much scope bandwidth do you have available? Also, how fast a
risetime can you generate in a pulse?
Also as Stefan mentioned, if you can get down to a nS, you should be
able
to get pretty close!
I'd recommend (for the long term) that you keep an eye on ebay for a
good
deal on a Tektronix 1502 TDR. One of the handiest units I have. A
person
can't have too many TDRs though! Check out a 7S12 when you have time.
Absolutely delightful! :-)
The 1502 (not a/b/c) certainly has a tunnel diode in it for the main
generator. It is difficult to impossible to get ahold of when damaged
(and it damages easily since it's right across the input). If you do
get a 1502, make sure that the TD is working.
I don't know anything about the 1502 A/B/C, so I cannot speak of the
tunnel diode (if any) in it.
A 1503 does not have a TD to generate the pulse, has 10 times the
distance at effectively 1/10 the resolution, that is, if the 1502
would be good to 1 cm, the 1503 is good to 10 cm.
Harder to damage, though.
Harvey
Best of luck with the cable!
Tom
