Rob

#78449

1st as always, Thank you for the band width and time....

I am currently working my way through a set of 7A12's that came with my
"pile". I have 2 of them working and the 3rd has issues when switching to
ground, AC,DC and DC Offset. In addition it will sometimes 'bleed' across
channels. By this I mean if there is a signal on one channel the other
channel will show it as a much reduced wave form even if the other channel
is in ground, etc.. 

I am reasonably certain that I have trouble shot the issue to a bad (I think
the technical term is flaky) relay. The reason for my post is that several
of the relays are listed as 148-0034-01. However in all three plug-ins the
relays are stamped with different numbers. They all have the 148-0034-01 at
the bottom but the top has a three digit number and a red dot. 

My question is: Are the relays interchangeable if they all have the
148-0034-01 number or does the dot and three digit number have meaning?
These relays are sealed so doesn't look to be any way to clan the contacts.
I guess I am curious if anyone has figured out a way to service these or sub
them or is it a matter of having to find good ones? 

Any other insight you would like to share concerning TEK relays would assist
my learning curve as well so please feel free to enlighten me.. 

I am on the road again so if I could find the answers to my question by
doing a forum search. Please let me know. I don't want to waste
time/bandwidth but I will not be able to research past posts until Wed or
so.

Rob

#78450

Hi,

Taking the risk to bore some others:

Some repair details and useful photos on Tek relais 0148-0034-00 can be found on Ralf's homepage here: ?
This is a different version from your -01, but shall be helpful anyway.

The page is in German, but your favourite on-line translator shall help.

Cheers,

Magnus

Rob

#78464

开云体育

Thank you Magnus.

?

The pictures on that website shows the three numbers and the red dot I am talking about very well. The numbers on mine are all different but the same in any plug-in. They are 304, 706 and 902 (as I recall from memory so may not be 100% correct). Does anyone know what these 3 numbers printed on the top with the red dot mean? and do those numbers matter for substitution or just the 140-0034-xx? I am assuming that the –xx is like most Tektronix parts where they are equivalent upgrades from the original -00 then -01, etc. Is this the case?

?

I may also try the repair shown on the website unless I find I can swap relays. I now have a 7A12 that is only good for parts. Because the front panel knobs were forced in through the pots inside in shipment or some such. They are not repairable so I am just going to part that one out. Making all of its relays available for the other two.

?

Thanks again for the bandwidth and any comments/insight.

Rob

?

Show quoted text

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of magnustoelle
Sent: Sunday, July 22, 2012 2:14 PM
To: TekScopes@...
Subject: [TekScopes] Re: A question of Relays

?

Hi,

Taking the risk to bore some others:

Some repair details and useful photos on Tek relais 0148-0034-00 can be found on Ralf's homepage here: ?
This is a different version from your -01, but shall be helpful anyway.

The page is in German, but your favourite on-line translator shall help.

Cheers,

Magnus

#78480

I have repaired a couple of 7A13 and 7A12 plug-ins which use the same
relays.  I never found an explanation for the numbers marked on the
top.

For the SPDT pinout Tektronix used, you can bend the pins on this
narrow body DPDT relay and by using both poles, it becomes a direct
plug in SPDT replacement:



If I have to substitute for any of the DPDT ones, I will probably cut
the base off of a bad one and wire a functional replacement into it as
shown in the web site.

The relays that I have had that failed did so because the armature
rusted under the plating and the rust built up until it could not
completely close.  Apparently they also fail because of a film
deposited on the contacts do to out gassing.  In both cases, it may be
possible to fix by cycling the relay on a pulse or function generator
for an extended period of time.

On Sun, 22 Jul 2012 17:04:30 -0500, "Rob" <rgwood@...>
wrote:

Thank you Magnus.

The pictures on that website shows the three numbers and the red dot I am
talking about very well. The numbers on mine are all different but the same
in any plug-in. They are 304, 706 and 902 (as I recall from memory so may
not be 100% correct). Does anyone know what these 3 numbers printed on the
top with the red dot mean? and do those numbers matter for substitution or
just the 140-0034-xx? I am assuming that the -xx is like most Tektronix
parts where they are equivalent upgrades from the original -00 then -01,
etc. Is this the case?

I may also try the repair shown on the website unless I find I can swap
relays. I now have a 7A12 that is only good for parts. Because the front
panel knobs were forced in through the pots inside in shipment or some such.
They are not repairable so I am just going to part that one out. Making all
of its relays available for the other two.

Thanks again for the bandwidth and any comments/insight.

Rob

From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of magnustoelle
Sent: Sunday, July 22, 2012 2:14 PM
To: TekScopes@...
Subject: [TekScopes] Re: A question of Relays

Hi,

Taking the risk to bore some others:

Some repair details and useful photos on Tek relais 0148-0034-00 can be
found on Ralf's homepage here:

fier/amplifier_7A11.htm
This is a different version from your -01, but shall be helpful anyway.

The page is in German, but your favourite on-line translator shall help.

Cheers,

Magnus

Rob

#78485

Thank you David. Exactly what I needed (I am reading into your send a bit
but sounds like as long as the TEK numbers match the numbers on top are not
an issue).... Now if we can only get someone to enlighten us on the meaning
of the numbers on top. 

Before I do anything else I am going to take the suggestion and cycle them a
bunch as I see no rust. 

Thanks again, I hope this finds you well
Rob

Show quoted text

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of David
Sent: Sunday, July 22, 2012 8:41 PM
To: TekScopes@...
Subject: Re: [TekScopes] Re: A question of Relays

I have repaired a couple of 7A13 and 7A12 plug-ins which use the same
relays.  I never found an explanation for the numbers marked on the top.

For the SPDT pinout Tektronix used, you can bend the pins on this narrow
body DPDT relay and by using both poles, it becomes a direct plug in SPDT
replacement:

irtualkey769-TN2-12V

If I have to substitute for any of the DPDT ones, I will probably cut the
base off of a bad one and wire a functional replacement into it as shown in
the web site.

The relays that I have had that failed did so because the armature rusted
under the plating and the rust built up until it could not completely close.
Apparently they also fail because of a film deposited on the contacts do to
out gassing.  In both cases, it may be possible to fix by cycling the relay
on a pulse or function generator for an extended period of time.

On Sun, 22 Jul 2012 17:04:30 -0500, "Rob" <rgwood@...>
wrote:

Thank you Magnus. 

The pictures on that website shows the three numbers and the red dot I 
am talking about very well. The numbers on mine are all different but 
the same in any plug-in. They are 304, 706 and 902 (as I recall from 
memory so may not be 100% correct). Does anyone know what these 3 
numbers printed on the top with the red dot mean? and do those numbers 
matter for substitution or just the 140-0034-xx? I am assuming that the 
-xx is like most Tektronix parts where they are equivalent upgrades 
from the original -00 then -01, etc. Is this the case?

I may also try the repair shown on the website unless I find I can swap 
relays. I now have a 7A12 that is only good for parts. Because the 
front panel knobs were forced in through the pots inside in shipment orsome such.
They are not repairable so I am just going to part that one out. Making 
all of its relays available for the other two.

Thanks again for the bandwidth and any comments/insight.

Rob

From: TekScopes@... [mailto:TekScopes@...] On 
Behalf Of magnustoelle
Sent: Sunday, July 22, 2012 2:14 PM
To: TekScopes@...
Subject: [TekScopes] Re: A question of Relays

Hi,

Taking the risk to bore some others:

Some repair details and useful photos on Tek relais 0148-0034-00 can be 
found on Ralf's homepage here:

ampli
fier/amplifier_7A11.htm
This is a different version from your -01, but shall be helpful anyway.

The page is in German, but your favourite on-line translator shall help.

Cheers,

Magnus
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