CDV-700 headset repair. - Page 1
Forum section: electronics / repair

author: XOIIO
author_rank: Super Contributor
timestamp: July 14, 2014, 07:07:38 pm
content: Hello all, as mentioned in my other thread (linked at bottom, can't figure out hyperlink) my CDV-700 headset worked for a brief period, then stopped, so I needed to fix it.I started by taking the headpiece apart, and while it was rusty and it bad shape, it did seem fine. (not to mention it had been working anyways)Then, while I was probing for a signal with it connected, I did not get anything, though testing at the Geiger counter itself I did get a signal (well, voltage that would be the signal), I thought that maybe I had a bad connection, then this happened, turns out I did have a bad connection after all, just not with the probesSo, the next step was to fix this, something which I had no clue to do, but figured out.There is a small screw on the side of the headphone connector, take that out, and you will be able to remove the spring that works as some minor strain relief.The next step, though somewhat optional, is to remove the threaded collar to gain easier access on the piece, to do this you slide it back and spin it counter clockwise, there is some threading on the main body of the headphone connector that serves to keep it in place.After that, there was the issue of actually fixing the headphone wire, I could not see how I could get a soldering iron down in the body of the connector to hook on to the end, thinking maybe it popped out, but then I took a closer look at the contact on the inside, and it looked a lot like solder, so I applied a hot iron and it readily melted. With a solder sucker, I cleaned it out, and the small bit of wire that was left fell out quite easily, leaving a nice clean hole. It seems to be a rivet through some Bakelite material.Afterwards, you want to cut the old wires and worn copper, if there is any left, for me only one wire had some left and it was in bad shape. Strip some new lengths, and tin one side, I used the same side as was previously connected though I am unsure if it would matter. Leave the other end plain.Next, feed the wire through the strain relief and collar, then, separate the wires, and first feed the tinned wire through the middle the get it through the rivet hole. Once you have it through, bend it to the side, put an angle in the copper wire, and feed that through the screw hole in the side of the connector body.Then, solder the main wire, and trim it, cutting into the solder a bit to reduce the point as much as you can, then heat the solder again so that it flows, you want a bit of a bulge to make a nice contact for with the connector on the Geiger counter itself.After this, slide the strain relief spring into place, making sure the copper wire on the side does not move. Place the screw in, and tighten it down, securing the spring and the wire. For the final step, slide the collar down, and screw it onto the threading until you feel it become loose, it is then properly in place.Hook it up and test it out, you now should have a working headset. It if does not work check the connections in the earphone to make sure they have not shaken loose over the years, mine were still in good shape.https://www.eevblog.com/forum/chat/today-was-a-good-day-(wait-that's-an-understatement)-cold-war-tech-image-heavy/

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 14, 2014, 07:16:21 pm
content: Feeding the "ground" wire out through the threaded hole, and then screwing in the grub-screw tends to actually shear off the end of the ground wire between the threads.I found it more reliable to fold the (un-tinned, stranded) ground wire back over the outside of the metal spring as you insert it, so that the ground wire is squeezed between the spring and the body of the connector when the grub-screw is tightened.

author: XOIIO
author_rank: Super Contributor
timestamp: July 14, 2014, 07:22:08 pm
content: Quote from: Richard Crowley on July 14, 2014, 07:16:21 pmAh, that would be a good solution. I plan of re-doing this and maybe using some hot glue or epoxy to improve the strain relief properties, right now there are practically non existent, even with that spring. I'm not sure how tight the fit is but a tinned wire might be thick enough for a tight fit between the casing and the spring

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 14, 2014, 08:20:52 pm
content: Quote from: XOIIO on July 14, 2014, 07:22:08 pmI would NOT tin that wire. Leaving it UN-tinned makes it better at handling strain and movement. it also makes it easier to flatten out the strands so they fit between the spring and the shell.I typically use graduated layers of heat-shrink tubing to make strain-relief and diameter-differential "hacks" for connectors like that.

author: XOIIO
author_rank: Super Contributor
timestamp: July 14, 2014, 10:37:42 pm
content: Oh, if anyone knows a place to get the headphone connector let me know, I know that anythingradioactive sells adapters, but I would like to just wire an old speaker up to it.

author: N2IXK
author_rank: Frequent Contributor
timestamp: July 14, 2014, 11:45:18 pm
content: Those old Amphenol microphone connectors are terrible things. I would consider replacing with a 1/4" phone jack and plug that you can easily get nowadays. They were common at one time on low end test gear (scopes, signal generators, VTVMs, etc), and are easily replaced with BNCs in those applications.

author: XOIIO
author_rank: Super Contributor
timestamp: July 14, 2014, 11:47:25 pm
content: Quote from: N2IXK on July 14, 2014, 11:45:18 pmYeah, I do have 1/4" jacks I could salvage but I would like to keep this original.

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 15, 2014, 05:12:27 am
content: Quote from: XOIIO on July 14, 2014, 11:47:25 pmThese days, 1/4 inch phone plugs look pretty "retro" and "steam-punk".Or you could leave it and "hide" a tiny 3.5mm jack somewhere unobtrusive.You could even drill out the center rivet from the Amphenol mic connector and put a 3.5mm jack there!

author: Stonent
author_rank: Super Contributor
timestamp: July 15, 2014, 02:53:35 pm
content: Quote from: XOIIO on July 14, 2014, 10:37:42 pmYou can take a PL259 RF connector and cut the center pin to a small nub and it works as a replacement.Also you technically can't wire a speaker directly to the audio port because they don't have enough impedance.I recommend a piezo element, in fact I posted a youtube video on it. A good source for a nice loud piezeo element is an old smoke detector, or one of those magnetic window alarms they sell at Dollar Tree. The magnetic window alarm is the same case as one of the CDV-700 passive speakers they sell online so I assume they just gutted it and painted it yellow.

author: XOIIO
author_rank: Super Contributor
timestamp: July 15, 2014, 02:58:34 pm
content: Quote from: Stonent on July 15, 2014, 02:53:35 pmAh, cool. Don't think I have any cables with those around but I'll keep it in mind.

author: Stonent
author_rank: Super Contributor
timestamp: July 15, 2014, 03:00:57 pm
content: Quote from: XOIIO on July 15, 2014, 02:58:34 pmMore on the audio I mentioned above.https://www.google.com/?gws_rd=ssl#q=jasonthepcmd+cd-700+youtubeYou can get the PL259 plugs at Radio Shack or equivalent.

author: XOIIO
author_rank: Super Contributor
timestamp: July 21, 2014, 09:54:41 am
content: Well, knew I had seem those uhf connectors around somewhere, my truck at some point in it's life had a CB radio. The antenna connections were ruined, but the one inside was still good. Chopped that off, and man it is a pain to try and re-use one of those. No grinding wheel so I had to use tin snips to get the post down, took off the crimped part to get the wires out, tried to drill out the squished hole in the pin, and the white plastic slipped out. Tried again but the pin insert just span, so got that out, drilled the hole out, now I need to find my file to smooth it out, get it in the plastic, put that in the metal case, then actually connect the wires. Not sure if the insert for the pin can be soldered to, hopefully it can, and I probably can solder to the outer case too but it won't be pretty, but I will have either an external speaker or 3.5mm audio adapter.I will still buy one from everythingradioactive.com (or whichever site that sells it) since it will be more compact and durable.

author: XOIIO
author_rank: Super Contributor
timestamp: July 21, 2014, 02:35:27 pm
content: Eh, the uhf connector doesn't thread down far enough on to the amphenol connector.Anyways, it is really tempting to put in a 3.5mil jack, and I'd like to hide it in the amphenol connector, if I found a narrow enough one that used the small nut to secure on to the panel, that would be perfect, it would look good, and also might, just might, allow the original headset to work with it since it is a metal ring, though the ones I have seen thread on to plastic.Anyways, there are some of those connectors on ebay, I am not sure if they would work 100% though, but I could order it. I thought the CDV-700 one was molded in but it is not.edit: oh hey found a site that sells the male connector with lead for a couple bucks, that would be worth ordering a couple to experiment with.edit2: they don't ship internationally anymore apparently, emailing to see if they ship to Canada still.