I've recently gotten hold of a Tektronix 7633 oscilloscope but can't seem to get a trace or any kind of waveform on the crt. Was wondering if I'm doing something wrong , not doing something right , or is the scope in need of repair? Is the repair complex ( I know my way around a soldering iron ) or should I just sell it for parts.
It came with three plug-ins : Dual trace amplifier , curve tracer , and dual time base.
Tried two different function generators and the output from my 4-watt transceiver. No joy. Any help would be greatly appreciated.
Thank you.
Mike AB8CQ
Tektronix 7633 o'scope
Started by ●October 17, 2017
Reply by ●October 17, 20172017-10-17
On Tue, 17 Oct 2017 12:53:05 -0700, mkoch583 wrote:> I've recently gotten hold of a Tektronix 7633 oscilloscope but can't > seem to get a trace or any kind of waveform on the crt. Was wondering > if I'm doing something wrong , not doing something right , or is the > scope in need of repair? Is the repair complex ( I know my way around a > soldering iron ) or should I just sell it for parts. > It came with three plug-ins : Dual trace amplifier , curve tracer , > and dual time base. > Tried two different function generators and the output from my 4-watt > transceiver. No joy. Any help would be greatly appreciated. > Thank you.Are you familiar with scopes at all? Any useful answer will need to be based on your degree of experience with them. Have you owned CRT-based scopes before? -- This message may be freely reproduced without limit or charge only via the Usenet protocol. Reproduction in whole or part through other protocols, whether for profit or not, is conditional upon a charge of GBP10.00 per reproduction. Publication in this manner via non-Usenet protocols constitutes acceptance of this condition.
Reply by ●October 17, 20172017-10-17
On Tuesday, October 17, 2017 at 5:20:14 PM UTC-4, Cursitor Doom wrote:> On Tue, 17 Oct 2017 12:53:05 -0700, mkoch583 wrote: > > > I've recently gotten hold of a Tektronix 7633 oscilloscope but can't > > seem to get a trace or any kind of waveform on the crt. Was wondering > > if I'm doing something wrong , not doing something right , or is the > > scope in need of repair? Is the repair complex ( I know my way around a > > soldering iron ) or should I just sell it for parts. > > It came with three plug-ins : Dual trace amplifier , curve tracer , > > and dual time base. > > Tried two different function generators and the output from my 4-watt > > transceiver. No joy. Any help would be greatly appreciated. > > Thank you. > > Are you familiar with scopes at all? Any useful answer will need to be > based on your degree of experience with them. Have you owned CRT-based > scopes before? > > > > -- > This message may be freely reproduced without limit or charge only via > the Usenet protocol. Reproduction in whole or part through other > protocols, whether for profit or not, is conditional upon a charge of > GBP10.00 per reproduction. Publication in this manner via non-Usenet > protocols constitutes acceptance of this condition.I'm not an expert with scopes but , as I'm wishing to get back into homebrewing radio gear , I think one would be a very useful instrument to have on the bench. Looking at my original post , I suppose it's obvious that I've got a lot to learn , but this is something that I want to pursue in retirement ( I'm 64 ). About 15 years ago I owned a Sencore scope but sold it when I moved to a new house. Never really learned how to use it. But as I said , just trying to get at least a horizontal line on the crt. Then I can figure it out from there. Thanks. Mike AB8CQ
Reply by ●October 17, 20172017-10-17
On most Teks with plugins if you unplug the vertical ones you should get a line across the screen. Just leave the horizontal in. Put it o auto. If that doesn't work switch it to external input. If that doesn't work remove the horizontal as well, which on some will result in a spot in the center of the screen. Also good test points are the deflection plates, which are usually on the sides of the neck of the CRT. You can tell the vertical ad horizontal pairs. The voltages should be close on each element of a pair but not necessarily pair to pair. Schematics are available on the net, if the voltages match but are all off from what the print says look to the power supply. Of course if removing any plugin restores the trace or spot, look at that first. It is a bit rough to measure the high voltage directly but there are telling test points, usually the focus control. Good luck with it. If it does turn out to be one of the plugins, they are available. They are not scrap prices yet so I guess there is a significant number of these old beasts that work.
Reply by ●October 17, 20172017-10-17
<mkoch583@gmail.com> wrote in message news:c69172c3-493f-4fff-ab14-23b79e8da125@googlegroups.com... On Tuesday, October 17, 2017 at 5:20:14 PM UTC-4, Cursitor Doom wrote:> On Tue, 17 Oct 2017 12:53:05 -0700, mkoch583 wrote: > > > I've recently gotten hold of a Tektronix 7633 oscilloscope but can't > > seem to get a trace or any kind of waveform on the crt. Was wondering > > if I'm doing something wrong , not doing something right , or is the > > scope in need of repair? Is the repair complex ( I know my way around a > > soldering iron ) or should I just sell it for parts. > > It came with three plug-ins : Dual trace amplifier , curve tracer , > > and dual time base. > > Tried two different function generators and the output from my 4-watt > > transceiver. No joy. Any help would be greatly appreciated. > > Thank you. > > Are you familiar with scopes at all? Any useful answer will need to be > based on your degree of experience with them. Have you owned CRT-based > scopes before? > > > > -- > This message may be freely reproduced without limit or charge only via > the Usenet protocol. Reproduction in whole or part through other > protocols, whether for profit or not, is conditional upon a charge of > GBP10.00 per reproduction. Publication in this manner via non-Usenet > protocols constitutes acceptance of this condition.I'm not an expert with scopes but , as I'm wishing to get back into homebrewing radio gear , I think one would be a very useful instrument to have on the bench. Looking at my original post , I suppose it's obvious that I've got a lot to learn , but this is something that I want to pursue in retirement ( I'm 64 ). About 15 years ago I owned a Sencore scope but sold it when I moved to a new house. Never really learned how to use it. But as I said , just trying to get at least a horizontal line on the crt. Then I can figure it out from there. Thanks. Mike AB8CQ ++++++++++++++++++++++++++++++++ You can get a copy of the manual here: http://w140.com/tekwiki/wiki/7633 Tektronix manuals are an education in their own.
Reply by ●October 17, 20172017-10-17
On Tuesday, October 17, 2017 at 9:00:51 PM UTC-4, jurb...@gmail.com wrote:> On most Teks with plugins if you unplug the vertical ones you should get a line across the screen. Just leave the horizontal in. Put it o auto. If that doesn't work switch it to external input. If that doesn't work remove the horizontal as well, which on some will result in a spot in the center of the screen. > > Also good test points are the deflection plates, which are usually on the sides of the neck of the CRT. You can tell the vertical ad horizontal pairs. The voltages should be close on each element of a pair but not necessarily pair to pair. > > Schematics are available on the net, if the voltages match but are all off from what the print says look to the power supply. Of course if removing any plugin restores the trace or spot, look at that first. > > It is a bit rough to measure the high voltage directly but there are telling test points, usually the focus control. Good luck with it. If it does turn out to be one of the plugins, they are available. They are not scrap prices yet so I guess there is a significant number of these old beasts that work.
Reply by ●October 17, 20172017-10-17
On Tuesday, October 17, 2017 at 9:00:51 PM UTC-4, jurb...@gmail.com wrote:> On most Teks with plugins if you unplug the vertical ones you should get a line across the screen. Just leave the horizontal in. Put it o auto. If that doesn't work switch it to external input. If that doesn't work remove the horizontal as well, which on some will result in a spot in the center of the screen. > > Also good test points are the deflection plates, which are usually on the sides of the neck of the CRT. You can tell the vertical ad horizontal pairs. The voltages should be close on each element of a pair but not necessarily pair to pair. > > Schematics are available on the net, if the voltages match but are all off from what the print says look to the power supply. Of course if removing any plugin restores the trace or spot, look at that first. > > It is a bit rough to measure the high voltage directly but there are telling test points, usually the focus control. Good luck with it. If it does turn out to be one of the plugins, they are available. They are not scrap prices yet so I guess there is a significant number of these old beasts that work.Thanks. I'll give it a go tomorrow. Mike
Reply by ●October 18, 20172017-10-18
mkoch583@gmail.com wrote:> > Thanks. I'll give it a go tomorrow.And don't forget that the plugins are not hot-pluggable!!!
Reply by ●October 18, 20172017-10-18
On Tue, 17 Oct 2017 17:39:46 -0700, mkoch583 wrote:> On Tuesday, October 17, 2017 at 5:20:14 PM UTC-4, Cursitor Doom wrote: >> On Tue, 17 Oct 2017 12:53:05 -0700, mkoch583 wrote: >> >> > I've recently gotten hold of a Tektronix 7633 oscilloscope but can't >> > seem to get a trace or any kind of waveform on the crt. Was >> > wondering if I'm doing something wrong , not doing something right , >> > or is the scope in need of repair? Is the repair complex ( I know my >> > way around a soldering iron ) or should I just sell it for parts. >> > It came with three plug-ins : Dual trace amplifier , curve tracer , >> > and dual time base. >> > Tried two different function generators and the output from my >> > 4-watt transceiver. No joy. Any help would be greatly >> > appreciated. >> > Thank you. >> >> Are you familiar with scopes at all? Any useful answer will need to be >> based on your degree of experience with them. Have you owned CRT-based >> scopes before? >> >> >> >> -- >> This message may be freely reproduced without limit or charge only via >> the Usenet protocol. Reproduction in whole or part through other >> protocols, whether for profit or not, is conditional upon a charge of >> GBP10.00 per reproduction. Publication in this manner via non-Usenet >> protocols constitutes acceptance of this condition. > > I'm not an expert with scopes but , as I'm wishing to get back into > homebrewing radio gear , I think one would be a very useful instrument > to have on the bench. Looking at my original post , I suppose it's > obvious that I've got a lot to learn , but this is something that I want > to pursue in retirement ( I'm 64 ). > About 15 years ago I owned a Sencore scope but sold it when I moved to > a new house. Never really learned how to use it. > But as I said , just trying to get at least a horizontal line on the > crt. Then I can figure it out from there. Thanks. > > Mike AB8CQThings to check (being extremely careful to not touch any cathode circuits until/unless you've verified that cathode voltage is discharged - it's probably around -2kV and enough current capacity to kill!): * make sure filament voltage is present. can you see any glow? is filament open? * verify that Z-axis isn't too negative relative to cathode (will extinguish any beam). This potential is used to blank between sweeps so may be hard to measure. If your 'scope has an X-Y mode that might turn it on for a long time and allow use of a DMM. * is cathode voltage as negative as manual indicates? * verify that V,H deflection plates aren't wildly off. You could disconnect all 4 plate pins, connect to ground - do you get a dot mid-screen? My memory has faded. Is this the variable persistence model? That would complicate matters.
Reply by ●October 18, 20172017-10-18
On Tuesday, October 17, 2017 at 9:00:51 PM UTC-4, jurb...@gmail.com wrote:> On most Teks with plugins if you unplug the vertical ones you should get a line across the screen. Just leave the horizontal in. Put it o auto. If that doesn't work switch it to external input. If that doesn't work remove the horizontal as well, which on some will result in a spot in the center of the screen. > > Also good test points are the deflection plates, which are usually on the sides of the neck of the CRT. You can tell the vertical ad horizontal pairs. The voltages should be close on each element of a pair but not necessarily pair to pair. > > Schematics are available on the net, if the voltages match but are all off from what the print says look to the power supply. Of course if removing any plugin restores the trace or spot, look at that first. > > It is a bit rough to measure the high voltage directly but there are telling test points, usually the focus control. Good luck with it. If it does turn out to be one of the plugins, they are available. They are not scrap prices yet so I guess there is a significant number of these old beasts that work.There are three plug-ins on this unit ( none of which are just horizontal or vertical ): curve tracer , dual trace amplifier supplying the channel 1 and channel 2 inputs , and a dual time base. I pulled the curve tracer. No dice. I swapped the dual trace amp with the dual time base. No good. I cleaned all of the terminals on the back of each plug in. I even pulled out all of the plug-ins. No luck. There are no inputs on the main oscilloscope itself so I have to rely on the dual trace amp plug-in to input a signal. I've downloaded a copy of the user and service manuals so I'm going to look it over. Thank you all for your time. ( PS ) I also have a BK Precision scope that works well but it's only 10 MHz bandwidth. I really need the 100 MHz for rf work.
