7M13 buttons


EJP
 

Just acquired a working 7M13 but the C and H buttons are broken. The 10-way button assembly doesn't have a Tek part number in the manual, it is just listed as an assembly. Is there any source for it? or another solution to the broken buttons? They still function if you probe something in there.

TIA

EJP


 

Hi Esmond,
The 7M13 has always been one of my favorite plugins for over 35 years because:
* They were always listed at ridiculously cheap prices;
* They were so good for documenting the scope photos I like to take;
* Every time I use it I am reminded of my wonderful friend Barrie Gilbert who invented the On-Screen readout

And now for the bad news: They are not easy to find. So be prepared to search eBay religiously every week so you don't miss one. Fortunately the price should be reasonable when one appears.

I can send you an entire row of 10 pushbutton switches from a 7A12 plugin. The buttons are clear but they look like they are the same shape as the white ones in the 7M13. If that will help you contact me off list.
Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of EJP
Sent: Monday, March 08, 2021 6:26 PM
To: TekScopes@groups.io
Subject: [TekScopes] 7M13 buttons

Just acquired a working 7M13 but the C and H buttons are broken. The 10-way button assembly doesn't have a Tek part number in the manual, it is just listed as an assembly. Is there any source for it? or another solution to the broken buttons? They still function if you probe something in there.

TIA

EJP







--
Dennis Tillman W7pF
TekScopes Moderator


EJP
 

For the record I find it is Tek part no. 670-2940-00. It is given in the components list, not the hardware list.

The 7A12 parts Dennis mentions are 670-1077-01 and 670-1084-01, right and left respectively, and include a PCB at the inner end.

EJP


EJP
 

Sadly the 7A12 parts Dennis mentioned are not the same. Very sad as I had found a source for them new here: https://www.smcelectronics.com/tekpart.htm.

1. The buttons on the 7A12 parts are latching where the 7M13 buttons aren't. This may or may not be a showstopper, as the 7M13 has electronic latching, but the physical latching may interfere with that.

2. The plastic rivets that retain the PCB to the switch body are in different places. Again not insurmountable but an issue.

3. Showstopper is that the electrical contact layout is different, so the 7M13 PCB does not electrically marry up to the 7A12 switches.

In other words the switch assemblies are definitely different. This is also visible at the inside ends of the switches, which look quite different in each case.

For the record here is the 7M13 disassembly procedure I used.

1. Prise off the front panel of the 7M13 with a small screwdriver head, starting from the bottom centre, and clearing the latch tag.

2. Remove the nut and washer from the camera trigger connector.

3. Remove the 4 screws at the back end securing the interface slotting to the chassis. Remove one screw securing the PCB to a flange near the front. You don't need to remove the spacer between the main PCB and the motherboard.

4. Partially withdraw the main PCB and the motherboard to the rear, far enough so you can pull the motherboard up and out of the chassis while leaving it connected to the main PCB. You need the motherboard up and out of the way for the next step. It only comes out one way, due to the flange mentioned above. This process will release several dozen pin-and-sleeve connections from the motherboard to the switch assemblies.

3. At the front, remove the three screws from the switch assembly you want to repair. Do this wth the chassis vertical, standing on its rear end, so as not to lose the screws. The assembly should now drop out.

4. At this point you can either remove the PCB from the switch assembly and move it to a new one, or else 3D-print and glue on some short rectangular-section extenders for the broken button(s). I will do the latter, after filing the broken surface a bit flatter for better adhesion. If you remove the PCB, DO NOT unsolder anything, as this will loosen ten delicate contact mechanisms that would otherwise just come out with the PCB, which is a better option. Just gently apply heat from a heat gun to the round black plastic rivet heads while levering upwards against them until the PCB pops off each one in turn. This is surprisingly easy. When replacing, apply heat the same way to re-melt the rivet heads.

(You could in theory do the gluing after step 1 without removing anything but the front plate. but you'd be running a lot of risk of getting the glue into unwanted places.)

5. Reassembly is the reverse of the above. Have fun getting all the motherboard pins in at the same time ;-)

Thanks to Dennis for the assistance.

EJP


Ed Breya
 

How about other plugs like the 7D20 and its accessory units (DF1 or DF2, I think), or 7A16P. Maybe some of those button/switch parts are the same - or not.

Ed


 

Hi Esmond,
I just checked every one of about 50 push button switch assemblies I have removed from 7000 series parts mules. I never noticed this before now, but every single one latches. The only exception to this seems to be the push button you press when you want a Single Sweep on the time base plugins.

The only plugins that don't use any latching push buttons are the programmable 7000 plugins like the 7A16P, 7A29P and 7B90P, and the 7D20. Also the DF1 and DF2 formatters for the 7D01 don't use the latching push buttons. I don't have any of these that I can use for parts mules

Some of the newer TM5000 plugins which are programmable don't have latching plugins. For example, the FG5010 and SG5010 switches that you press to specify the frequency you want them to generate, are momentary. I don't have any of these that I can use for parts mules.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of EJP
Sent: Saturday, May 08, 2021 9:37 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7M13 buttons

Sadly the 7A12 parts Dennis mentioned are not the same. Very sad as I had found a source for them new here: https://www.smcelectronics.com/tekpart.htm.

1. The buttons on the 7A12 parts are latching where the 7M13 buttons aren't. This may or may not be a showstopper, as the 7M13 has electronic latching, but the physical latching may interfere with that.

2. The plastic rivets that retain the PCB to the switch body are in different places. Again not insurmountable but an issue.

3. Showstopper is that the electrical contact layout is different, so the 7M13 PCB does not electrically marry up to the 7A12 switches.

In other words the switch assemblies are definitely different. This is also visible at the inside ends of the switches, which look quite different in each case.

For the record here is the 7M13 disassembly procedure I used.

1. Prise off the front panel of the 7M13 with a small screwdriver head, starting from the bottom centre, and clearing the latch tag.

2. Remove the nut and washer from the camera trigger connector.

3. Remove the 4 screws at the back end securing the interface slotting to the chassis. Remove one screw securing the PCB to a flange near the front. You don't need to remove the spacer between the main PCB and the motherboard.

4. Partially withdraw the main PCB and the motherboard to the rear, far enough so you can pull the motherboard up and out of the chassis while leaving it connected to the main PCB. You need the motherboard up and out of the way for the next step. It only comes out one way, due to the flange mentioned above. This process will release several dozen pin-and-sleeve connections from the motherboard to the switch assemblies.

3. At the front, remove the three screws from the switch assembly you want to repair. Do this wth the chassis vertical, standing on its rear end, so as not to lose the screws. The assembly should now drop out.

4. At this point you can either remove the PCB from the switch assembly and move it to a new one, or else 3D-print and glue on some short rectangular-section extenders for the broken button(s). I will do the latter, after filing the broken surface a bit flatter for better adhesion. If you remove the PCB, DO NOT unsolder anything, as this will loosen ten delicate contact mechanisms that would otherwise just come out with the PCB, which is a better option. Just gently apply heat from a heat gun to the round black plastic rivet heads while levering upwards against them until the PCB pops off each one in turn. This is surprisingly easy. When replacing, apply heat the same way to re-melt the rivet heads.

(You could in theory do the gluing after step 1 without removing anything but the front plate. but you'd be running a lot of risk of getting the glue into unwanted places.)

5. Reassembly is the reverse of the above. Have fun getting all the motherboard pins in at the same time ;-)

Thanks to Dennis for the assistance.

EJP







--
Dennis Tillman W7pF
TekScopes Moderator