Making your own TM500 containers, some surprises!


For those looking around for an easy way to make TM500 compatible housings, here are a few thoughts:

1. Tek 5000 series Scope plug-ins have the EXACT same metalwork, and are perfect organ donors for your new TM500 plug in. These are 5A and 5B series items. They are NOT plug compatible, however, so don't try and plug them in. These are often on ebay very cheaply. You will still have to make a new face, however.

2. While not obvious, the top and bottom extrusions are DIFFERENT in the plug ins, to fit the different keyways and positions in the frame. You can duplicate this effect with simple stand-offs (square profile), but they are costly. Replacements could be milled from an aluminum blank, but this is not such a simple task for most, and end holes would still have to be added. It's possible they could be 3D printed, but the ruggedness of the end holes would be a serious issue, but could be possibly aided by beefing up the edge area.

3. HOWEVER, I was curious to see if 7K plug ins have the same extrusion profile,, and THEY DO. TA-DA! They are LONGER, but can absolutely be cut down to make a working TM500 frame. So, it you have a bad 7K plug in (7A, 7B, 7T, 7S), you can be in business easily. You can in fact salvage enough mechanical parts to make a complete TM500 plug-n, and have some scrap metal left over. Yes, you still have to make a new face plate. This is probably the fix most can use.

4. The Tek TM500 toolbox plug in is an ideal candidate to make a new test plug in, the front is blank, and all the right mechanical parts are present. It has a solid back, which can be modified to allow the PCB to mate. It is a magical fix for this task, as the "build-your-own plug in" kits from Tek have all long ago disappeared.

5. If you are making a test plug in (for the frame), there is absolutely no point to the lock/pull tab, it just adds difficulty, and is best removed. A lightweight rack handle to easily insert and remove the plug in is a LOT more useful in real life.
I can send anybody interested a picture of how my own test plug in was made to show this handy feature.

Many people have at least one scrap 7K plug-in laying around, so the answer to your problems may already be in your junkbox. I do have 2 TM500 tool boxes left cheaply, and all kinds of lightweight handles if you need them. Please contact me off list if you do. I did add a huge pile of lab power supplies to the Stuff Season page to get ready for spring, you can see them here: I apologize for not having them up earlier, they were sitting in the waiting to do pile, and I finally got around to them, and there are more still to go up. Some pretty cool units there, including my all-time favorite Xantrex supplies from right here in BC.

All the best,
walter (walter2 -at-
sphere research corp.

Ed Pavlovic

You’re correct on the 5000 series scope plug in shells, I picked one up last week on eBay for under $10 plus shipping. And the best part about it will be that a knob or two and some of the plastic button frames will be used to fix up my 465 as well, so it some of the parts I’m not needing for the mainframe tester are still being re-used as well.


Clark Foley

Good advice for scavenging parts for a TM500 plugin. Take care with the 7k bottom extrusion. It has a tab to land the latch spring. 7k mainframe rails have a slot to accommodate the latching mechanism. The TM500 mainframe rails do not have the slot. Before using the 7k bottom extrusion on a TM500 rail, you will need to flatten the tab. It feels great to fix something with a hammer (other than to start that old Ford)!



On that annoying tab, you can just cut the *fron**t* part off the extrusion, rather than the back.
save the hammer for adjustments later...

what's making me crazy is that I had a big stock box full of scavenged plug-in tops and bottoms,
and I have no idea what became of it.  rats...


Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:-
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)


I was dubious about the talk of "junker" TM-500/5000-series/7000-series plugins, but stayed silent on the principle that a person saying that a thing can't be done should not interfere with the person actually doing it. Now, however, I am a convert: I just got a TM506 with 6 plugins installed, and one of the plugins (a DC503) had it's face stove-in, which basically destroyed one of the barrel switches and may have done other damage that I can't evaluate without completely disassembling the unit (several small pieces fell out when I was removing the plugin from the power frame, one appears to be a copper leaf spring from the barrel switch, the other escaped into the wild).

If the damage is as bad as I fear then this will be good for little more than parts, so I guess I'm up for building a TM500 test plugin (I'm not looking to get into the group buy at this point, as I have some ideas of my own about how to connect the controls to the main board, that do not coincide with Jared's design).

-- Jeff Dutky