A flexible 7k extender? I'm thinking about it (was: 7B92 with no repeating sweep)


John Griessen
 

On 10/17/21 15:17, Jeff Dutky wrote:
A flexible 7k extender? I'm thinking about it.
(actually I'm thinking about something a little more involved: a plug-in with both a pin connector for a flexible extension, and some indicators for 7k backplane health. I'm reading about 7k cal fixtures, and wondering if I can build some of that functionality in as well)
You'll want to talk to me about my experience selling 200+ of them, and about a man named Jerry Massengale, who made some rigid extenders from plugin cages, my connectors and pcb's and added the indicators and BNC jacks you are thinking of. The short version is, "This group is not a bunch of big spenders..."

--
John Griessen -- building lab gear for biologists
Austin TX blog.kitmatic.com


 

I was just wondering how much I would spend, in total, to avoid buying one of the genuine Tek flexible extenders on the auction site. The genuine articles have asking prices of $400 or more. I already have a few junker 7k plug-ins that will provide the frame, but those cost me something like $40, so that's the starting point. I plan to have PCBs made, so that's another $15-$25, and then I'll need 7k-compatible card edge socket ($5-$10), and assorted bits and bobs ($???). It sounds like I can get it all done for well under the $400 cost of a Tek-made extender.

I'm not really thinking of selling them, mainly because I don't have a good source for the aluminum frames (other than junker plug-ins), but I'm well aware that the market is small and tight-fisted (speaking as a member of the target market). I could probably 3D-print the plastic rear plate, but I expect that the top and bottom aluminum frames would be challenging to make.

I've also got a 7B92A that shuts the mainframe down when it's installed. I'm not sure how to go about diagnosing and fixing it, but it occurred to me that an extender with current limits on the power rails might be of some use.

-- Jeff Dutky


Harvey White
 

Figure perhaps 2 dollars or more for each of the two boards. Connectors I've found at about 8 dollars each.  Add in LEDS, IDC connectors, ribbon cable, and depends on where you can find junked plugins.

Certainly less than the 400 dollars.

You'll want to 3D print the front plate, though.

Harvey

On 10/17/2021 6:02 PM, Jeff Dutky wrote:
I was just wondering how much I would spend, in total, to avoid buying one of the genuine Tek flexible extenders on the auction site. The genuine articles have asking prices of $400 or more. I already have a few junker 7k plug-ins that will provide the frame, but those cost me something like $40, so that's the starting point. I plan to have PCBs made, so that's another $15-$25, and then I'll need 7k-compatible card edge socket ($5-$10), and assorted bits and bobs ($???). It sounds like I can get it all done for well under the $400 cost of a Tek-made extender.

I'm not really thinking of selling them, mainly because I don't have a good source for the aluminum frames (other than junker plug-ins), but I'm well aware that the market is small and tight-fisted (speaking as a member of the target market). I could probably 3D-print the plastic rear plate, but I expect that the top and bottom aluminum frames would be challenging to make.

I've also got a 7B92A that shuts the mainframe down when it's installed. I'm not sure how to go about diagnosing and fixing it, but it occurred to me that an extender with current limits on the power rails might be of some use.

-- Jeff Dutky





 

Harvey,

The junked plug-ins are the least challenging item on the list: I've got a couple of 7A15ANs that were stored badly. They might be salvageable but I don't feel like I need very many sub-100 MHz single channel vertical amps. I've got one working one that I use with the 7CT1N, and that's about the limit of my use cases.

I was just going to cut the front plate from sheet plastic, or include it in the PCB order, but 3D printing is on my list of things to do. I don't see the 7k rear plat on Thingiverse, which means I will need to figure out how to do the CAD-thing.

-- Jeff Dutky


Harvey White
 

Contact me off list.

On 10/17/2021 8:54 PM, Jeff Dutky wrote:
Harvey,

The junked plug-ins are the least challenging item on the list: I've got a couple of 7A15ANs that were stored badly. They might be salvageable but I don't feel like I need very many sub-100 MHz single channel vertical amps. I've got one working one that I use with the 7CT1N, and that's about the limit of my use cases.

I was just going to cut the front plate from sheet plastic, or include it in the PCB order, but 3D printing is on my list of things to do. I don't see the 7k rear plat on Thingiverse, which means I will need to figure out how to do the CAD-thing.

-- Jeff Dutky





Leo Potjewijd
 

As for the frames: I designed (quite a while back) an extrusion profile that is usable for both the top and bottom rails; even investigated the manufacturing cost (I was planning to build several extenders and other measuring devices).
Needless to say, it never came to that...
If anyone is interested, I can dig in the archives on another computer to find out what the quote was, but IIRC it was only viable with an order of 50+ pieces.