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Re: Replace/Repair TM 500 Module Side Panel Latch

 

The trick to gluing the two halves together, if that is necessary, is avoiding the adhesive binding against the side panel itself. This leaves little surface area to bond between the two halves. I¡¯ve got more pondering to do on that option. I have one broken one. The other one I figured out how to separate the two without breaking something. I used a pair of hemostats to pinch the locking ears on the external piece. With the hemostats I was able to pinch and gently push, ultimately popping the external half out of the internal latch piece. And, using care, was able to do so without damaging the ears and core of the external piece so much that I can¡¯t reassemble it. Is it marred? Yes, but it¡¯s minimal.


Re: Replace/Repair TM 500 Module Side Panel Latch

 

On Tue, Jul 20, 2021 at 04:59 PM, Jeff Dutky wrote:


Anybody know what that latched cover is for?
Jeff,

PG506 has them on at least some examples. These are used only on plug-ins that include the rear support frame. I will need to look as I think I have a couple of others which have the same side covers and latch mechanisms. .

--
Michael Lynch
Dardanelle, AR


Re: Recreating an old board for the 7854

 

Which one is Q510? I see 2 Q500s but no Q510. Of course it could just be me.

Vince.

On 07/20/2021 08:48 PM, Zentronics42@... wrote:
I have uploaded the schematic that I have drawn up in Kicad in the files section. Given the new information for Q500 and Q510 I think I will need a different part in CR511. I need to figure out how to make Kicad do a PCB edge connecter. But here is the work so far. Since I am still in the schematic phases and have not started laying down foot prints I need to decide thru hole or SMD construction. The transistors will be SOT-23 so they are SMD.

Zen
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of GeorgeP
Sent: Tuesday, July 20, 2021 6:05 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

On Tue, Jul 20, 2021 at 01:13 PM, <Zentronics42@...> wrote:


When the design is checked and tested If there is any interest in
these let me know. Not sure how many out there want to tackle a full cal of a 7854.
I am interested. Thanks!









--
Michigan VHF Corporation -- nobucks dot net
K8ZW -


Re: Recreating an old board for the 7854

 

I have uploaded the schematic that I have drawn up in Kicad in the files section. Given the new information for Q500 and Q510 I think I will need a different part in CR511. I need to figure out how to make Kicad do a PCB edge connecter. But here is the work so far. Since I am still in the schematic phases and have not started laying down foot prints I need to decide thru hole or SMD construction. The transistors will be SOT-23 so they are SMD.

Zen

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of GeorgeP
Sent: Tuesday, July 20, 2021 6:05 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

On Tue, Jul 20, 2021 at 01:13 PM, <Zentronics42@...> wrote:


When the design is checked and tested If there is any interest in
these let me know. Not sure how many out there want to tackle a full cal of a 7854.
I am interested. Thanks!


File /Tektronix 7854 Test Card PCB files/7854 Test Card Preliminary Schematic.pdf uploaded #file-notice

[email protected] Notification
 

The following files have been uploaded to the Files area of the [email protected] group.

By: Zentronics42@...

Description:
1st run at the schematic for the 7854 Test Card


Re: Replace/Repair TM 500 Module Side Panel Latch

 

Hmmm... Silly me, at a glance I always thought these were just good old fashioned Dzus fasteners, but that shows how little I know about Tek's passion to custom build everything. :-)

Keith


Re: Recreating an old board for the 7854

 

On Tue, Jul 20, 2021 at 02:13 PM, <Zentronics42@...> wrote

When the design is checked and tested If there
is any interest in these let me know. Not sure how many out there want to
tackle a full cal of a 7854.

Zen

Eric,

I am certainly interested the boards as well.

Thanks,

Shaun M.


Re: Replace/Repair TM 500 Module Side Panel Latch

 

By latched cover, do you meant just the blank cover?? I have two of them, used for improving airflow and keeping debris and fingers out of empty compartments.
-Dave

On Tuesday, July 20, 2021, 02:59:54 PM PDT, Jeff Dutky <jeff.dutky@...> wrote:

Before we start trying to manufacture a replacement (which I think is a fine idea, especially in this new age of 3D printing) I'm wondering if there is a Tek part number for these? I have the cover, but not the thing it goes to (whatever thing that is). I don't expect to find a service manual for the TM500 toolbox, but the perforated cover must go to something other than the toolbox.

Anybody know what that latched cover is for?

I have been unsuccessful in separating the two halves of my damaged latch, but I've been trying to do so non-destructively, as I'd like to have them to take dimensions off of. It looks like the halves snap together, as I said, but more specifically there appear to be compressible, one-way flanges on the inner shaft that lock the halves together. There are also two vertical flanges (very thin) that engage one half to the other, and it appears that those have sheared off in my failed latch, so that the two halves now rotate independently.

If I can get a good set of measurements on the two halves I could try to draw up and print a replacement. I'd think hat you could design a sturdier version of this part that wouldn't tend to fail in this way (e.g. rather than a circular shaft with flimsy vertical flanges, why not make the shaft square, or rectangular? It would be much less likely to shear off if there were more material).

-- Jeff Dutky


Re: Replace/Repair TM 500 Module Side Panel Latch

 

On Tue, Jul 20, 2021 at 05:59 PM, Jeff Dutky wrote:

Before we start trying to manufacture a replacement (which I think is a fine
idea, especially in this new age of 3D printing) I'm wondering if there is a
Tek part number for these?
The latch part numbers should be 105-0932-00 and 214-3364-00.

They are described in great detail in the Mechanical Common Design Parts Catalog
from November 1988.


dan


Re: Recreating an old board for the 7854

 

On Tue, Jul 20, 2021 at 01:13 PM, <Zentronics42@...> wrote:


When the design is checked and tested If there is any interest in these let me
know. Not sure how many out there want to tackle a full cal of a 7854.
I am interested. Thanks!


Re: Replace/Repair TM 500 Module Side Panel Latch

 

Before we start trying to manufacture a replacement (which I think is a fine idea, especially in this new age of 3D printing) I'm wondering if there is a Tek part number for these? I have the cover, but not the thing it goes to (whatever thing that is). I don't expect to find a service manual for the TM500 toolbox, but the perforated cover must go to something other than the toolbox.

Anybody know what that latched cover is for?

I have been unsuccessful in separating the two halves of my damaged latch, but I've been trying to do so non-destructively, as I'd like to have them to take dimensions off of. It looks like the halves snap together, as I said, but more specifically there appear to be compressible, one-way flanges on the inner shaft that lock the halves together. There are also two vertical flanges (very thin) that engage one half to the other, and it appears that those have sheared off in my failed latch, so that the two halves now rotate independently.

If I can get a good set of measurements on the two halves I could try to draw up and print a replacement. I'd think hat you could design a sturdier version of this part that wouldn't tend to fail in this way (e.g. rather than a circular shaft with flimsy vertical flanges, why not make the shaft square, or rectangular? It would be much less likely to shear off if there were more material).

-- Jeff Dutky


Re: Working on the HV Section of a 533A

 

Dave,

I suspect that all three of the tips I have are worn out. I discovered two tips, still in their bags, in a plastic "parts deresser" (plastic drawers for electronic parts, cheap a Radio Shack, back in the day). One is a long conical point (my favorite style) 700¡ãF tip, and the other is a 600¡ãF screwdriver tip (though it looks conical to me). I also ordered a half dozen new Weller tips on Amazon of various styles and temperatures, including a pretty broad "sloped" tip (but it's 800¡ãF, so maybe not appropriate for most work). I'll be sure to order a couple more 600¡ãF tips, if I can find them in broader styles.

The TC201 is very nice to use. My father had another, much cheaper soldering iron (or "pencil") that plugged directly into the wall (the two prong power cord came straight out the back of the handle). The TC202 seemed like ridiculous extravagance back in 1985. The fact that you could just unscrew the outer sleeve and swap the tips was astonishing. I'm still sorry that I didn't know how to take care of the tips properly, or they would probably still be in good condition.

I've watched a few videos about proper care of your soldering iron and tips, and I'm going to give a go at correctly cleaning and tinning the tips I already have, but I'll be more focused on keeping the new ones in better condition.

-- Jeff Dutky


Re: Recreating an old board for the 7854

 

Any chance there is high rez photos of a production analog test board? I have only seen the scan in the manual and I have some questions about layout and locations. Like of the BNC connector. I can get measurements off the Digital board cause they share dimensions. But there is a pin connector and a BNC connector I have some questions about where they go and why they are there.

Zen

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Clark Foley
Sent: Tuesday, July 20, 2021 4:23 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

Time for the Cone of Silence before we get the OT warning!

Now back to the 7854.
I use the board to run my analog backup 7854 parts. It has no Max, I mean smarts, in it. I kludged in 7k readout board and now I have a fully functional 7804. Some of the boards are early prototype boards and some from different production runs. Think of Johnny Cash¡¯s ¡°One Piece At A Time.¡± No fins on it though!


Re: Recreating an old board for the 7854

 

Time for the Cone of Silence before we get the OT warning!

Now back to the 7854.
I use the board to run my analog backup 7854 parts. It has no Max, I mean smarts, in it. I kludged in 7k readout board and now I have a fully functional 7804. Some of the boards are early prototype boards and some from different production runs. Think of Johnny Cash¡¯s ¡°One Piece At A Time.¡± No fins on it though!


Re: Recreating an old board for the 7854

 

Looks like a suitable new chip would be this



Vce - 25Vdc
Hfe 120-240
Frequency - 800 Mhz

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Glenn Little
Sent: Tuesday, July 20, 2021 4:05 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

A web search shows Frequency as 500 MHz as guaranteed minimum.

Glenn

On 7/20/2021 3:49 PM, Zentronics42@... wrote:
Thanks for all the help.

I have about 80% finished with the schematic. I need to find a replacement for the 2N5769 The documentation says this was a "Switching Transistor" but it does not say the switching frequency. But that is the next hurdle that needs to be cleared. I will post the schematic and the board layout when it is finished to make sure I did not make any errors. Also need to get the pin outs for P190. At the moment P190 looks like it is the board edge connector.

All advise is welcome and thanks in advance.



-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Raymond
Domp Frank
Sent: Tuesday, July 20, 2021 3:28 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

On Tue, Jul 20, 2021 at 09:12 PM, Clark Foley wrote:


Would you believe octal latches? Sorry about that, Chief.
Since we're at it:
It's not 8 latches: There are 8 D-type flip-flops in a '374.
Latches pass the input with one control level (the output follows the input, no clock involved) and latch their input value with the control at the other level, much like an analog sample and hold. Compare 7475 (quad latch).
The '374 uses a clock to transfer the data at the D-inputs to the complementary outputs.

Raymond










--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class of the Amateur that holds the license"


Re: Recreating an old board for the 7854

 

That was the number I was unable to find. I had a feeling these needed to be fast as they are in the trigger circuit and the 7854 is a 400 Mhz frame. Test triggering to 500 Mhz is what I was expecting maybe even higher. Good news is as this is a from scratch board design package does not matter as I will be ordering parts. So for this spot I need lowish Vce and fast.
Ill keep working on the boards. When the design is checked and tested If there is any interest in these let me know. Not sure how many out there want to tackle a full cal of a 7854.

Zen

-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Glenn Little
Sent: Tuesday, July 20, 2021 4:05 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

A web search shows Frequency as 500 MHz as guaranteed minimum.

Glenn

On 7/20/2021 3:49 PM, Zentronics42@... wrote:
Thanks for all the help.

I have about 80% finished with the schematic. I need to find a replacement for the 2N5769 The documentation says this was a "Switching Transistor" but it does not say the switching frequency. But that is the next hurdle that needs to be cleared. I will post the schematic and the board layout when it is finished to make sure I did not make any errors. Also need to get the pin outs for P190. At the moment P190 looks like it is the board edge connector.

All advise is welcome and thanks in advance.



-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Raymond
Domp Frank
Sent: Tuesday, July 20, 2021 3:28 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854

On Tue, Jul 20, 2021 at 09:12 PM, Clark Foley wrote:


Would you believe octal latches? Sorry about that, Chief.
Since we're at it:
It's not 8 latches: There are 8 D-type flip-flops in a '374.
Latches pass the input with one control level (the output follows the input, no clock involved) and latch their input value with the control at the other level, much like an analog sample and hold. Compare 7475 (quad latch).
The '374 uses a clock to transfer the data at the D-inputs to the complementary outputs.

Raymond










--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class of the Amateur that holds the license"


Re: Recreating an old board for the 7854

 

At 2021-07-20 16:07, you wrote:
That?€?s because she?€?s 88. Wait until she?€?s 99!
So, two years ago she could have taken Max's place?


Re: Recreating an old board for the 7854

 

That¡¯s because she¡¯s 88. Wait until she¡¯s 99!


Re: Recreating an old board for the 7854

 

A web search shows Frequency as 500 MHz as guaranteed minimum.

Glenn

On 7/20/2021 3:49 PM, Zentronics42@... wrote:
Thanks for all the help.
I have about 80% finished with the schematic. I need to find a replacement for the 2N5769 The documentation says this was a "Switching Transistor" but it does not say the switching frequency. But that is the next hurdle that needs to be cleared. I will post the schematic and the board layout when it is finished to make sure I did not make any errors. Also need to get the pin outs for P190. At the moment P190 looks like it is the board edge connector.

All advise is welcome and thanks in advance.
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Raymond Domp Frank
Sent: Tuesday, July 20, 2021 3:28 PM
To: [email protected]
Subject: Re: [TekScopes] Recreating an old board for the 7854
On Tue, Jul 20, 2021 at 09:12 PM, Clark Foley wrote:


Would you believe octal latches? Sorry about that, Chief.
Since we're at it:
It's not 8 latches: There are 8 D-type flip-flops in a '374.
Latches pass the input with one control level (the output follows the input, no clock involved) and latch their input value with the control at the other level, much like an analog sample and hold. Compare 7475 (quad latch).
The '374 uses a clock to transfer the data at the D-inputs to the complementary outputs.
Raymond
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Re: Recreating an old board for the 7854

 

The transistor is not a fast one. Rise/fall times are on the order of 10ns to 20ns. Fine for TTL stuff.