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Tektronix 475 scope

A

Allan Mac

Jan 1, 1970
0
Hi,

the first anode (EHT) of my old 475 scope is arcing, either under the cap or to chassis. How do I get to it? (yes I have already got the outer casing off) Is it already a boat anchor?
Allan
 
M

mike

Jan 1, 1970
0
Hi,

the first anode (EHT) of my old 475 scope is arcing, either under the cap or to chassis. How do I get to it? (yes I have already got the outer casing off) Is it already a boat anchor?
Allan

is the display shrunk?
One failure mode is that the HV bleeder resistor goes open.
High voltage goes up.
Display shrinks depending on intensity level.
 
A

Allan Mac

Jan 1, 1970
0
Over 1000 members in this group to ask:



http://tech.groups.yahoo.com/group/TekScopes/



A lot of former Tek employees, knowledge & spare parts info.





You can download the manual here:

http://w140.com/tekwiki/wiki/475

Thanks for that. Been smelling ozone for a while, now nasty fizz from 1st anode area but can't see anything due to protective can. Don't want to leave it on long enough to look for display, was working ok. Have manual, no help.

Cheers Allan
 
T

tm

Jan 1, 1970
0
Allan Mac said:
Hi,

the first anode (EHT) of my old 475 scope is arcing, either under the cap
or to chassis. How do I get to it? (yes I have already got the outer
casing off) Is it already a boat anchor?
Allan

Grab a copy of the service manual (google) and read up on removing the CRT.
There is no removable HV PDA cap. The HV lead is soldered to an electrode
and potted in RTV. The 475 is a very fine 200 MHz scope and worth saving.

tm
 
A

Allan Mac

Jan 1, 1970
0
Hi,



the first anode (EHT) of my old 475 scope is arcing, either under the cap or to chassis. How do I get to it? (yes I have already got the outer casing off) Is it already a boat anchor?

Allan

Finally got around to tackling this. Found old RTV hard and conductive at anode connection. Removed, cleaned and replaced. Good fix. Many thanks for help.

Allan
 
Well since nobody else has the decency, thanx for letting us know. Alot of people get stuff fixed only to reemerge a year later with another problem.
 
Well I haven't had much luck with them lately. When my 7603 was running there were scads of them on eBay and everywhere for less than a hundred bucks, notny more.

Anyway, I dunno about requiring a DD214 to hold political office, but I do tnink they should have had at least one honest job in their life. Youknow what I mena by honest job right ? Well they don't.
 
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