Well I was able to get my hands on one of these today. I plan on using it for checking the high voltage power supplies on the oscilloscopes I am restoring. I am looking for an adapter so I can connect the WG-289 to a modern multi-meter (with selectable range of course). The multi-meters have general banana plug inputs on them.


What I had in mind so far was connecting large mic coax "this is what I think it is right now" MALE to MALE > Female large mic coax to BNC > BNC to Banana plugs.

Anyone have any better ideas? Or will this even work?

 

I remember using that probe with an RCA VTVM ... close to 40 years ago.

 

I remember using that probe with an RCA VTVM ... close to 40 years ago.

Yeah a VTVM would be ideal. Unfortunately, for majority of VTVMs that are around that I could use, time has gotten to the best of them. This probe however was somehow spared.

 

That plug looks familiar - is it the same thread as a PL259/SO239 connector?

If so, use an SO239 to BNC adapter with a cut-off 4mm pin permanently fitted so the surface is at the correct level to match the center contact of the plug.

You could then stack that with a twin 4mm adapter such as this, to fit a standard multimeter:
http://www.itcelectronics.com/product_info.php?cPath=1883_1892_1912&products_id=11813

 

Not a PL259. It's an old "microphone" connector. Had one on a VTVM too. Like this: http://www.surplussales.com/Connectors/Microphone-5.html

Maybe this: http://angela.com/microphoneconnectorswitchcraft14adapterforoldstylescrewonconnectors.aspx
plus this: http://www.guitarcenter.com/VTG-4044-Banana-to-1-4--Female-Adapter-103379632-i1170000.gc

ken

 

I actually have one of those probes, but not the instruction sheet.

We used to use them to test the high voltage on the radar transmitters' power supply.

Inspect the red insulator very carefully using a magnifying glass and plenty of light. If there are any cracks, it's not usable. Finger oils on the resistor are a bad thing; it will attract dust/dirt, and eventually start carbon tracking, resulting in a flashover.

Had a tech try to use one of those probes that had an insulator with a hairline crack. It flashed over to his hand, and he did a back-flip into a trash can that was behind him. Fortunately, he wasn't injured - so we laughed at him.

I haven't used the probe I have, for one because I haven't needed it yet, and also because I haven't been able to find a suitable connector.

 

Not a PL259. It's an old "microphone" connector. Had one on a VTVM too. Like this: http://www.surplussales.com/Connectors/Microphone-5.html

Maybe this: http://angela.com/microphoneconnectorswitchcraft14adapterforoldstylescrewonconnectors.aspx
plus this: http://www.guitarcenter.com/VTG-4044-Banana-to-1-4--Female-Adapter-103379632-i1170000.gc

ken

Geeze those are expensive adapters. Haha, I maybe better off fixing up one of the VTVM RCA [SIZE=-2]WV98Cs that are around and have a solid direct connection and avoid the adapters in the first place. [/SIZE]

Inspect the red insulator very carefully using a magnifying glass and plenty of light. If there are any cracks, it's not usable. Finger oils on the resistor are a bad thing; it will attract dust/dirt, and eventually start carbon tracking, resulting in a flashover.

The probe appears to be extremely solid. Wires are not brittle at all, and the red plastic insulator is still well together. This probe was still in the original tissue paper when I first opened the box. I don't think it was ever used... For the resistor. It is still extremely shinny, and appears to be very clean on both ends. I used a cloth to handle it so my finger oils would not touch it.

 

Not a PL259. It's an old "microphone" connector. Had one on a VTVM too. Like this: http://www.surplussales.com/Connectors/Microphone-5.html
...
ken

I didn't say it was a PL259, I asked if it was the same thread - some mike fittings use that exact same thread, meaning an SO239 could be adapted to work & that is a common, cheap connector.

 

My adapter-plus-adapter was done tongue-in-cheek.

Unless you are wanting to keep this in pristine, original condition, just cut off the old connector and replace it with one of these: http://www.radioshack.com/product/index.jsp?productId=2407246

ken

 

I didn't say it was a PL259, I asked if it was the same thread - some mike fittings use that exact same thread, meaning an SO239 could be adapted to work & that is a common, cheap connector.

Sorry. The mike connector is smaller than the old UHF connectors.

ken

 

My adapter-plus-adapter was done tongue-in-cheek.

Unless you are wanting to keep this in pristine, original condition, just cut off the old connector and replace it with one of these: http://www.radioshack.com/product/index.jsp?productId=2407246

ken

Yeah i'm probably best off just cutting it and retro fitting it.

 

UPDATE: Well I was thinking about it and I don't want to clip off the old mic connection on this prob. For it being in mint condition, I don't want to destroy that. So I decided just to grab a VTVM RCA WV-98A and get it working and use that. The one I got is in alright condition (battery leaked in it and covered almost everything in nasty stuff) but I cleaned most of that off. However when I cleaned up and got it going I couldn't seem so get a reading on anything. The controls did seem to respond but the needle was just kinda hay wire (wouldn't zero on some off the lower ranges on the DC+ function and vise verse for everything else). The electrolytic cap looks like it might have been replaced not too too long ago. It is newer looking than all the other. But everything else seems to be original. I'm guessing I should just replace the other caps too? Also there was a 5726 tube in the slot were a 6AL5 should have been. I know a 5726 can be a sub sometimes for a 6AL5 but it is alright in a VTVM? I tried different 12AU7s to see if the original was bad but the others preformed the same. Anyone have any helpful hints for me?

 

UPDATE:Well I was thinking about it and I don't want to clip off the old mic connection on this prob. For it being in mint condition, I don't want to destroy that.

So, I decided just to grab a VTVM RCA WV-98A and get it working and use that. The one I got is in alright condition (battery leaked in it and covered almost everything in nasty stuff) but I cleaned most of that off. However when I cleaned up and got it going I couldn't seem so get a reading on anything.

The alkaline material released tends to be pretty corrosive. Get all of that stuff off, and look at it under a magnifying glass to see if parts and/or traces are eaten through.

The controls did seem to respond but the needle was just kinda hay wire (wouldn't zero on some off the lower ranges on the DC+ function and vise verse for everything else). The electrolytic cap looks like it might have been replaced not too too long ago. It is newer looking than all the other. But everything else seems to be original. I'm guessing I should just replace the other caps too?

All electrolytics will likely need replacing.

Also there was a 5726 tube in the slot were a 6AL5 should have been. I know a 5726 can be a sub sometimes for a 6AL5 but it is alright in a VTVM?

The 5726 should be identical to a 6AL5W.
http://www.radiomuseum.org/tubes/tube_5726.html
The 6AL5 is similar to a 6AL5W.
http://www.radiomuseum.org/tubes/tube_6al5.html

I tried different 12AU7s to see if the original was bad but the others preformed the same. Anyone have any helpful hints for me?

Did you try using some contact cleaner?

Look for components, traces, and wiring that got eaten by the leaked battery.

 

Alright thanks i'll see what I can do.

 

Okay tomorrow I am going to go to the electronics store to by some caps. I have a question though on regarding some of the tests results from the caps that I tested in the VTVM. On some of the test caps that were listed as .1 \(\mu\)f at 1000v gave me a reading of .375 \(\mu\)f. Another was rated as .01 \(\mu\)f at 400v gave me a reading of .09 \(\mu\)f. Does this mean that they are bad?

 

Use <alt>0181 for the µ symbol.

Check this out, Alternate Symbols.

 

Thanks for the tip. What about the caps though?

 

What?!? You want a large omega as well as a small one!