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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 fineThe 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 |
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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 |
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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 |
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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.
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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! |
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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! |
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Re: Recreating an old board for the 7854
Looks like a suitable new chip would be this
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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.-- ----------------------------------------------------------------------- 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" |
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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.
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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.-- ----------------------------------------------------------------------- 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" |
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Re: Recreating an old board for the 7854
A web search shows Frequency as 500 MHz as guaranteed minimum.
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Glenn On 7/20/2021 3:49 PM, Zentronics42@... wrote:
Thanks for all the help. --
----------------------------------------------------------------------- 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" |
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Re: Recreating an old board for the 7854
Well, actress Barbara Feldon is still alive? evidently.? ?She's 88, though, so not nearly as hot as she was in Get Smart.? ? ? ?Jim?Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: Clark Foley <clarkfoley@...> Date: 7/20/21 12:49 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Recreating an old board for the 7854 Where is Agent 99 when you need her!
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Re: Recreating an old board for the 7854
You guys aren't as Smart as you think you are!? ? ? ? ? ? Jim Ford?Sent from my Verizon, Samsung Galaxy smartphone
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-------- Original message --------From: Tom Lee <tomlee@...> Date: 7/20/21 12:17 PM (GMT-08:00) To: [email protected] Subject: Re: [TekScopes] Recreating an old board for the 7854 Missed it by that much.Sent from my iThing, so please forgive typos and brevity.> On Jul 20, 2021, at 12:13 PM, Clark Foley <clarkfoley@...> wrote:> > ?Would you believe octal latches? Sorry about that, Chief.> > > > >
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Re: Recreating an old board for the 7854
Thanks for all the help.
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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: 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 |
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Re: Recreating an old board for the 7854
On Tue, Jul 20, 2021 at 09:12 PM, Clark Foley wrote:
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 |
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Re: Replace/Repair TM 500 Module Side Panel Latch
I have purchased TM500 plugins from reputable sellers (eg. Stewarts of Reading, Telford Electronics) and from less well-known purveyors on eBay and have found several broken latches of this type. The common "fix" seems to be to use a bit of some kind or insulated wire to wrap around the engaging parts. Since the casual observer will have no idea of this "fix" when the plug-in is in a power mainframe and in use, I can't see any problem with it. Of course, if someone were to manufacture facsimiles of the original latches and sell them at pocket-money prices, then I would be interested, but not at something like $50 each - that may be justifiable, but it is not economic, in my opinion. Others with deeper pockets may (and are welcome to) disagree.
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Colin. -----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Jeff Dutky Sent: 20 July 2021 19:36 To: [email protected] Subject: Re: [TekScopes] Replace/Repair TM 500 Module Side Panel Latch Cory, I have no experience replacing the latch, but I have a side cover that looks exactly like yours, where the latch seems to have broken internally: the slotted side rotates, but the latch side does not. I also have a TM500 "toolbox" with a solid cover and a similar latch mechanism. The latch seems to be made of two parts, the latch side and the slotted side, which snap together on a central shaft. I would expect that you could push the center shaft out of the latch side with a small screwdriver or punch, but I haven't tried this. If your latch is broken like mine, however, you don't have much to lose by experimentation (nor do I, so I will see what I can achieve). One solution would be to simply glue to the two halves of the latch together, maybe by dripping some epoxy down the hole on the latch side. This would be a fairly permanent fix (you would not be able to take the latch apart again without some amount of destruction) but I imagine a permanent fix is kind of what you are looking for. -- Jeff Dutky |
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Re: Looking for data on 9-pin Vacuum time delay relays used in old Tek-scopes
These can still be found as NOS on eBay. I bought a 6NO45T, a couple months back for around $10, for a Tek 551 I'm restoring. Turned out I didn't really need it. The main open-air PS relay that the timer triggers was sticky and had dirty contacts.
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GeorgeP
Raymond Domp Frank
Flannel Tuba