Trigger not working on my Tektronix 932A

[Drac0nic]

After a long moratorium I have decided to start getting back into working with electronics on a hardware level. I managed to trade a bottle of Maker's Mark for an oscilloscope off a coworker and the only issue it seems to have is the trigger won't work. If I move the level adjustment pot it will catch for a split second but won't "hold" at all. It's driving me batty as this is a perfectly operational scope except this minor detail. Does anyone with this series scope have any experience with this happening, if so where should I look?

 

[ghostman11]

i cant be much help i dont have that scope. but 2 things sprang to mind.... if it catches but wont hold are you sure you have all the setting correct? i have a scope that isnt set up spot on the trigger is a mare! the other thing that i thought of was the fact you said 'pot' if its a pot maybe the pot is worn/dirty bad contacts. sorry isnt much help.
this might be of use **broken link removed** its the manual at least you can check correct setup and section 7 has circuit diagrams (apparently as i didnt look to hard)

 

[ModemHead]

Tektronix: Troubleshooting Your Oscilloscope
https://www.electro-tech-online.com/custompdfs/2011/10/troubleshooting-scopes.pdf

I saw this posted on another forum recently. It has some good tips and procedures, straight from the our favorite 'scope makers. The triggering section stuff starts on page 76.

 

[unclejed613]

make sure the trigger is set to auto, and the source switch to the channel you're triggering from (if it's set to external, you need to have an input to the external trigger jack). set the trigger coupling to whatever is appropriate for the signal you're looking at. Tektronix triggering is usually the easiest and most stable trigger system to use of any scope manufacturer.

 

[Mikebits]

make sure the trigger is set to auto, and the source switch to the channel you're triggering from (if it's set to external, you need to have an input to the external trigger jack). set the trigger coupling to whatever is appropriate for the signal you're looking at. Tektronix triggering is usually the easiest and most stable trigger system to use of any scope manufacturer.

Actually setting the trigger to auto mode ignores trigger input and uses an internal timer. Normal mode uses external trigger.

 

[unclejed613]

in auto the presence of a triggering signal overrides the internal timer

 

[Reloadron]

Something to try. Using the probe comp output feed it into channel 1. Set triggering source to Channel 1, Triggering Mode to Normal. Trigger Coupling to DC and set the Slope to +. Set the sweep to 1 mS. Set the Channel 1 vertical gain to .2 V/Div. As you rotate the Trigger Level potentiometer does the scope trigger? Do you get a stable triggered trace?

Ron

 

[Drac0nic]

Well, I found my problem. Anyone know where I can dig a spare one up at or if any interchange? I am thinking about trying to find some tiny tiny screws then using a torch tip drill to fix this.

 

[Drac0nic]

managed to get the screws installed, I am going to finalize everything up with some epoxy later but it looks as if this is going to work. It has an ever so slight drift but it seems to be doing a lot more than it was before. Any thoughts on how I could get this to actually "hold?"

 

[bountyhunter]

Ebay has tons of cheap Tek scopes sold 'for repair only" for parts. They also have good used scopes very cheap, that's where I got my Teks.

 

[bountyhunter]

managed to get the screws installed, I am going to finalize everything up with some epoxy later but it looks as if this is going to work. It has an ever so slight drift but it seems to be doing a lot more than it was before. Any thoughts on how I could get this to actually "hold?"

It should be syncing on the same point of the waveform on each sweep.

 

[Tilamsik]

Well, I found my problem. Anyone know where I can dig a spare one up at or if any interchange? I am thinking about trying to find some tiny tiny screws then using a torch tip drill to fix this.

Its much be better if you spray contact cleaner on that part before deciding opening it up. Loose electrical contacts usually found with "used" oscilloscope. As I experienced with my 20 yr. old Leader Model 1021 20 mhz oscilloscope.
Usually I use small drill bit to put a hole in the casing of "rotary switch" so I can force contact cleaner in the contacts easily. That's technique solved intermittent problem of my old oscilloscope.

 

[atferrari]

Not a minor one

After a long moratorium I have decided to start getting back into working with electronics on a hardware level. I managed to trade a bottle of Maker's Mark for an oscilloscope off a coworker and the only issue it seems to have is the trigger won't work. If I move the level adjustment pot it will catch for a split second but won't "hold" at all. It's driving me batty as this is a perfectly operational scope except this minor detail. Does anyone with this series scope have any experience with this happening, if so where should I look?

Not a minor detail, really. That is what makes the scope useful.

 

[bryan]

This site has a fair amount of spare parts for older Tek's

https://www.sphere.bc.ca/test/tek-parts/tek-info.html

 

[Drac0nic]

It should be syncing on the same point of the waveform on each sweep.

It seems as if channel 1 is actually triggering right even if the adjustments are a bit finicky for it at the moment but channel 2 is not triggering properly at all. That should be a bit "easier" to trace down I think. Ironically enough it would probably be easier still if I had an oscilloscope I could do it with. Oh well, so goes life. A single channel with trigger should suit my purposes well enough.