¿ªÔÆÌåÓý

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. TekScopes
  2. Topics

one last 7633 question (for now)

 

I have no lights but I know they work. Im assuming because p10 is empty. I have looked at the schematic for hours but I cant figure out where the input to p10 comes from.
 

I presume you mean the illuminated push switches on the various plug-ins? If so then I'm afraid the answer is nowhere on the 3-slot chassis!

I believe the reason was a shortage of power in the 'smaller' mainframe but do not despair, Tek produced an app note/mod sheet (040-0686-01) that tells you how to add a standard voltage regulator to provide it.

If you google 'tektronix 040-0686-0' you will find it.

Have fun!
Adrian

On 2/28/2018 2:44 PM, lop pol via Groups.Io wrote:
I have no lights but I know they work. Im assuming because p10 is empty. I have looked at the schematic for hours but I cant figure out where the input to p10 comes from.
 

HAHAH. Thank you. That is good stuff. You are exactly right. Im'm going to wait until I get a donor parts 7633 to do that mod. Make her look pretty. Time to button her up for now.
 

While I intend to do this mod to my 7623A, it is worth bearing in mind a couple of things. If you check the app note/mod sheet (040-0686-01) you will see that some things should be down-rated afterwards - this might be significant to your needs. Also, those mainframes that had this power-supply for the push-switches as standard often had a switch where the light intensity could be turned down or completely off. It may be worth your while to include something like this, unless you like replacing the lamps in the switches on the plug-ins. Just a thought...
Colin.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of lop pol via Groups.Io
Sent: 28 February 2018 15:32
To: [email protected]
Subject: Re: [TekScopes] one last 7633 question (for now)

HAHAH. Thank you. That is good stuff. You are exactly right. Im'm going to wait until I get a donor parts 7633 to do that mod. Make her look pretty. Time to button her up for now.
 

On Wed, Feb 28, 2018 at 08:44 am, Colin Herbert wrote:

Also, those mainframes that had this power-supply
for the push-switches as standard often had a switch where the light intensity
could be turned down or completely off.
Note also that some plugins, notably the programmable ones (definitely 7A16P and 7B90P, probably 7A29P as well) use the 5V 'lights' supply to run their internal logic. They don't work at all in unmodified 76x3 mainframes, and neither do they work well in larger mainframes with the light intensity switched to 'dim'. I found that out the dumb way!

Chris
 

Details,details,details. Thanks for helping me not go crazy. I literally looked at that schematic for hours yesterday and today. Finally got to the "well i gotta ask" point. I told my wife I was too stupid to figure it out and to stubborn to give up. Glad I asked because it would have been another long day.
 

One thing that kinda threw me was no trigger light. Well just now looked inside my 7b53a and the previous owner had plugged in the pin header backwards. So the trigger light is now working. Jeesh
 

Also some plug-ins like the ubiquitous 7B53A used chiefly in 76xx
mainframes have no built in illumination anyway so adding the lamp
power modification to the mainframe makes no difference for them.

On Wed, 28 Feb 2018 16:43:38 -0000, you wrote:

While I intend to do this mod to my 7623A, it is worth bearing in mind a couple of things. If you check the app note/mod sheet (040-0686-01) you will see that some things should be down-rated afterwards - this might be significant to your needs. Also, those mainframes that had this power-supply for the push-switches as standard often had a switch where the light intensity could be turned down or completely off. It may be worth your while to include something like this, unless you like replacing the lamps in the switches on the plug-ins. Just a thought...

Colin.

1 - 8 of 8