Diathermy Xmtr

[W1GFH]

Seems to be in the 27 Mhz range...

http://cgi.ebay.com/Vintage-TUBE-SHORT-WAVE-DIATHERMY-Medical-Equipment_W0QQitemZ150401326757QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item23049e1ea5

Looks like just an oscillator tank circuit. Don't know what the tubes are. Nice standoffs. Very buzzardly. It occurred to me to be a cheap source of parts for...I dunno. Wonder if anyone ever cannibalized one for a xmtr project?

[flintstone mop]

WOW that looks really old.
I remember a battery charger that would be in a charging station with those huge bottle type tubes in it.

Fred

[Ian VK3KRI]

I have a diathermy machine I bought for parts. - 15 years later its still intact!  My one is in a wooden(!) box , uses two 125W triodes in push pull.  Basically a tuned cct acoss the grids, and another across the plates and voila - a couple of hundred watts of the DIRTIEST RF you've ever seen. Did I mention no filtering on B+ , or that power output appears to be varied by a HUGE wire wound resistor in series with the heaters....   I shudder just thinking about being treated with it.

                                                                                            Ian VK3KRI

[W7TFO]

I have bought several of just that type of old Diathermy machine off eBay over the years to get the parts.  One even had a pair of WECo 284C triodes that alone resold for a good profit.

The one in the post is using a pair of either T-55 or T-60 Taylor triodes in a self-rectifying setup.  Nice quality unit, too.  Vacuum cap, even.

dg

[W2PFY]

WOW that looks really old

That's a rather modern one Fred. They are still made and used in the medical profession. Mt grandfather had one. I remember when they used it at home on my grandmothers hands. We all got hooked up to it as kids and got a dose. They were outlawed by the FCC so my grandparents stopped using it. Something later it was given to me. It had some big tubes in it but I had no idea what the thing did or how it worked. I was able to take it apart and dismantle it to a point where it could not ever be put back together again.

[N0WEK]

Arggh!! Thread back from the dead...

I didn't really need more stuff but this one followed me home, cheap!

The Ebay ad from the original post is obviously long dead but this sounds like the same unit. T60s as a self-rectifying oscillator, good high grade parts. Majestic Elctro-Therm built in July 1953 if I'm reading the date code properly.

I can't check the parts since I'm on the road in Tulsa where I bought it at a junk store, I should at least carry a multimeter. I've just got it open and cleaned up at the motel.

If it works it'd probably kill CB for a 25 mile radius if hooked to an antenna. 27.12 Mc, most of the output circuit C is a vacuum cap with a very small trimmer cap in parallel.

If I come up with multimeter this weekend I'll at least be able to see if the transformer is OK and what voltage it's good for. The label says 120 volts @ 8 amps which implies about 8-900 watts for the transformer. Note that the filaments are in series which gives the unit some protection if one tube craps out.

I can't find specs on the Taylor T60s for some reason, does anybody here have them?

[N0WEK]

The plate choke seems to be a National R-175 and the loading cap is an EF Johnson 50E45. The meter is a Simpson 200 ma unit.

If nothing else it's a pretty good pile of high grade buzzardly parts for $37.00 and it's an interesting piece.

[W2PFY]

Wow a metal cabinet. All that I have seen were in an old wooden case. That could very easily be converted into a ten meter amp or a class C final for a couple hundred watts output..Attached is a link for one that did not sell on ePay that used a pair on 304TL's. It must have made a lot of power and I wonder if it was used on race horses or other large animals?

The T-60 tube is probably 60 watts plate dissipation so it perhaps the same power output of the plain 811, not the 811A.



http://www.ebay.com/itm/EIMAC-TRIODE-TUBES-VT129-304TL-HOMEBREW-AMPLIFIER-/201267799322?ssPageName=STRK%3AMESINDXX%3AIT&_trksid=p2047675.l2557&nma=true&si=SedupNCCqs0ksQrbLG9znOnKRZs%253D&orig_cvip=true&rt=nc

[John K5PRO]

I have a couple of Diathermy rigs, one is an ancient (1930s) ALOE in a wooden case. Still works. I made new rubber pads and giant banana pins for them with HV wire for cables. It will dry out a sponge in a few minutes. Or overheat the blood in you body. My family MD gave it to me in the 1980s, he was 95 at the time. He said he quit using it when he was treating gonorrhea with it and the patient expired when their temp was 105.
It has big triodes like Taylors, and a push pull unrectified circuit like you showed. It ran around 15-17 MHz with a nasty sound on the radio. The second one is a Crystal Bandmaster, has crystal control at 13.56 MHz, and something like 810s in it. This one is in metal, and has strange looking electrodes in black bakelite. I have never considered gutting them and making radios, as they are so cool as RF generators. The Aloe manual has strange surgery's and cutting that can be done with a probe, says to practice with raw steak before going to the patient!

[N0WEK]

Sounds like fun pieces and I share your reluctance to take it apart for parts.

I did manage to borrow a VOM and check out the tube filaments and the transformer, both of which are good. I'm still missing a power cord, Hubbell midget twist lock, but I'll find some way to feed it power and use a light bulb for dummy load for testing. I'll probably wipe out CB for a couple of miles around Tulsa.

I've got one of those newer small units at around 14 mc too, if it puts out clean power I figure it wouldn't take much to feed it with my generic 30 watt modulator and move it up to 20 meter AM, but not if it's got a circuit like this one (real broad and with a 120 cycle hum!)

[VE3LYX]

1940 Radio Handbook, seventh edition, page 498 has a chapter on radiotherapy and circuit descriptions and schematics. I have it right beside right now. I have an ancient TIG HF welder. I wonder whats inside it?
don

[N0WEK]

Well the transformer is good. I clip leaded a power cord, checked the filament voltage with the borrowed digital VOM (12.4 volts, the T60 filaments are in series), and discovered that the plate voltage, with the tubes removed, is WAY above the maximum 750 volt AC setting on the VOM. There was a POP so bright it showed right through the red opaque case of the VOM, there are a couple of surface mounted parts in there that no longer exist. Luckily it was a $1.50 special from Harbor Freight.

It took the 14 amp fuse too. I'll get a new fuse and see how it lights up the 200 watt bulb dummy load! The plate voltage measurement will have to wait until I get home and my higher voltage meters.

[W3RSW]

What fun!  True wall socket experiments. Bet you feel like your back in eighth grade when all the world was a wonder and nothing stopped you from seeing what would happen if you did this... then this.  Oh! Then this!  Blam! Did'ja see that?
So Kuhl.

[N0WEK]

What fun!  True wall socket experiments. Bet you feel like your back in eighth grade when all the world was a wonder and nothing stopped you from seeing what would happen if you did this... then this.  Oh! Then this!  Blam! Did'ja see that?
So Kuhl.

It gives me something to do while sitting in a motel for two weeks in Tulsa between overnight freight flights. 

The fuse will probably cost me as much as the meter.

Does anybody have the specs on the Taylor T-60?

I can find stuff on the T-40, and figure the T-60 is pretty much the same with an extra 20 watts of plate dissipation? Nice graphite plates on the pair.

[WA2SQQ]

Just curious, at what frequency did these diathermy devices operate? Back in the mid 60’s, in my “criminal band” days, CB CH23 had a 24 x 7   S9+20 signal on it that would broadcast sets of three low frequency tones. Some said it was used to control the traffic lights in Newark (NJ) and others insisted it was medical diathermy devices. I’ve never been able to find out what it was that made CH23 totally unusable.

[w1vtp]

Arggh!! Thread back from the dead...

I didn't really need more stuff but this one followed me home, cheap!

The Ebay ad from the original post is obviously long dead but this sounds like the same unit. T60s as a self-rectifying oscillator, good high grade parts. Majestic Elctro-Therm built in July 1953 if I'm reading the date code properly.

I can't check the parts since I'm on the road in Tulsa where I bought it at a junk store, I should at least carry a multimeter. I've just got it open and cleaned up at the motel.

If it works it'd probably kill CB for a 25 mile radius if hooked to an antenna. 27.12 Mc, most of the output circuit C is a vacuum cap with a very small trimmer cap in parallel.

If I come up with multimeter this weekend I'll at least be able to see if the transformer is OK and what voltage it's good for. The label says 120 volts @ 8 amps which implies about 8-900 watts for the transformer. Note that the filaments are in series which gives the unit some protection if one tube craps out.

I can't find specs on the Taylor T60s for some reason, does anybody here have them?

It's a fascinating subject.  One of my friends from way back got one.  It's basically a big PS, maybe  final and maybe parts for a tank circuit..  Lay some stuff down inside - maybe deadbug it and presto, you got yer final.  Just up with some mod iron (which was surprising scarce back then) and you had a damn good medium powered  AM rig

There really isn't much inside those things so lots of space to create your vintage "monstah" AM rig

[W2VW]

This type of stuff still shows up on 11 and 10 meters when the bands are open. One can hear them fweep by.

Eastern Europe and South America are two of my guesses of where they are still in use.

[w1vtp]

Why bother with the T-60s.  Just build a final around a pair of 812s.  There's plenty of good ideas floating around on using those classic twins

[Tim WA1HnyLR]

 AHHHH Yes A   diathermy mosheen would make a great high band SBE rig. Just include a plate modulator. and properly filter the power supply. Change the ocill-O-tron tank components to put it on 75. 3890 could use some cleansing.
Tim WA1HnyLR

[John K5PRO]

You're lucky you didn't get bit or worse, from that meter. Figure a diathermy will put out 200 watts or so, and you're over 750 VAC quickly. I remember a guy working at DuPont who died or got knocked off a scaffold, when he decided to probe a 13.2 kV AC circuit with a Simpson 260. These days Fluke DMMs have Cat III and Cat IV ratings. They can take a transient overload while reading a powerline voltage, and not blow up so quickly. It might be an electrical code thing.

Many of the old dual tube diathermy are in the 13-17 MHz range, and they either free oscillated and wandered or were crystal controlled on 13.56 MHz or 27.12 Mhz. My Bircher "bandmaster" is MOPA configuration, with a crystal oscillator.
The really early ones with a slate top or side plate and small quenched spark gaps, radiated horrendous noise, but I don't know their frequency. Essentially spark gap transmitters feeding the flexible plates (applicators). Here is an example of what they could do.
 

[Opcom]

last diathermy parts I got included a transformer with 2000VCT so maybe 750 is on the low side for some of them.

[N0WEK]

You're lucky you didn't get bit or worse, from that meter. Figure a diathermy will put out 200 watts or so, and you're over 750 VAC quickly. I remember a guy working at DuPont who died or got knocked off a scaffold, when he decided to probe a 13.2 kV AC circuit with a Simpson 260. These days Fluke DMMs have Cat III and Cat IV ratings. They can take a transient overload while reading a powerline voltage, and not blow up so quickly. It might be an electrical code thing.

Many of the old dual tube diathermy are in the 13-17 MHz range, and they either free oscillated and wandered or were crystal controlled on 13.56 MHz or 27.12 Mhz. My Bircher "bandmaster" is MOPA configuration, with a crystal oscillator.
The really early ones with a slate top or side plate and small quenched spark gaps, radiated horrendous noise, but I don't know their frequency. Essentially spark gap transmitters feeding the flexible plates (applicators). Here is an example of what they could do.
 

I had the tube out of it so should have just read the secondary of the transformer, but I may have got an inductive kick from measuring at the top of the plate choke. I had it set up with clip leads and my hands and other parts well clear when I popped the meter. It's still in the trunk since I got home but I'll pull it out this weekend and see what's up with my Simpson meter which will do 5,000 volts. Hopefully I didn't kill the transformer or plate choke, although I have a spare choke.

It runs at 27.12 mc.