[GreenKeys] Re: bringing an M33-asr-twx to life

[wa2hwj at att.net]

Gil et al,

The CCU for the TWX 33 has two cables routed to the 101 "dataset" that
terminate with 25-pair Amphenol connectors. The tip and ring telephone line
coming out of the dataset can be attached right to a standard telephone circuit (red and green).
Many of the TWX machines had the automatic card dialer. It's
purely a mechanical spring-loaded device which then "keys" a standard
TouchTone keypad. The punch cards are thin plastic. These dialers will
probably last forever, if they are clean and lubricated. However, the TT pad electronics seems to die in many of the older TouchTone sets. A few of the the card dialer mechanisms have been on Ebay recently. They were WU surplus from the (now) legendary Paterson, NJ, warehouse.

It is possible to dig out the keyboard and selector magnet driver
connections and use the machine as if it were the basic "Line/Local"
configuration. The connections can be found on the terminal strips
inside the dataset. If I can find my 101C schematics, I'll pass along
the terminal numbers. They used to be marked with some kind of cryptic ID since Bell often modified the machines for external keyers, test sets, etc. 

Jack WA2HWJ

NNNN


-------------- Original message from gil smith : -------------- 

> Hi Bob: 
> 
> A quick ramble (corrections appreciated, if I have any of this wrong): 
> 
> The first thing I did with my 33 was to remove the cover and blow out dirt 
> with compressed air. I don't know whether this might force dirt into the 
> wrong places or not, but I got a lot of chads and crud out this way. Then 
> it would be a good idea to lube it, if you know where to apply oil and 
> grease. Mine looked pretty well lubed, so I have not done this yet. Then 
> the cover went back on. 
> 
> To assemble, the legs need to be bolted to the stand, and then the main 
> unit needs to be bolted to the stand. Once the unit is together, look 
> under the chassis to see if the seller put a shipping screw in a middle 
> hole -- if so, remove the shipping screw (this screw keeps the typing unit 
> from moving around during shipment). 
> 
> The small power supply is only for the tape reader, and clips in position 
> at the top of the stand (from the rear, of course). See a picture of it at 
> (scroll down): 
> http://www.vauxelectronics.com/gil/tty/M33.htm 
> There will be a polarized molex cable from the main unit, that will plug 
> into this PS. 
> 
> If you scroll down to the bottom of that web page, you will see a picture 
> of the paper cards used for the very-cool phone-number-card-reader that you 
> have in your twx ccu. This is the first card reader option I have seen, 
> and I'd like to see some closer pics when you get a chance. 
> 
> There will also be a cable or two from the ccu that connects to the dataset 
> (modem), which I believe normally sits inside the stand. From the dataset, 
> there should be a cable for connecting to a phone line. I never got this 
> far with my 33-twx, and then I got a 33 private wire machine, so the twx is 
> in storage. 
> 
> I don't know whether the dataset hooks directly to a phone line or needs 
> another interface box. I think it connects directly, but you should ask on 
> greenkeys for more info. Folks like Jack know a lot more about 33s than I 
> do. 
> 
> Your 33 has the 101C modem, which was pretty common, and documented. My 
> 33-twx machine has a 101D modem, for which I cannot locate schematics (and 
> it has a problem of some sort). 
> 
> If all is well with your unit at this point, you should be able to power up 
> the unit in Local mode (button labeled LCL or something like that). In 
> local mode, an internal 48V supply powers the internal loop, and allows you 
> to type on the keyboard and see the typing unit (and tape punch, if turned 
> on) working. 
> 
> If you punch a tape, you can the test the reader as well. Move the lever 
> down to STOP or FREE, load the tape, the flip the lever up to START, and 
> the unit should print. 
> 
> If you get this far, you could try putting the 33 into ANSWER mode, and 
> connecting to a phone line or pbx extension. Then use a computer terminal 
> emulator at 110-baud, 8-bits, 2-stop-bits, no-parity (I think), and connect 
> it to an old 0-to-300-baud fsk modem (bell 103 standard?). I think most PC 
> internal modems will do this also, but when I peeked at HyperTerminal, 
> selecting the internal modem limited the lowest speed choice to 300 baud, 
> which won't work. However, when selecting a com port in HyperTerminal, it 
> allows 110-baud, so at least an external modem should work. If the modem 
> says it supports 300 baud, it should also support 110-baud, since it is fsk 
> and merely has a max speed of 300. You will then need to use the 
> appropriate dialing command to dial the phone number or pbx extension 
> (ATDT...). If all goes well, the 33 will answer and you can 
> communicate. I think. 
> 
> Nuther option would be to tap into the 20-mA loop inside the CCU, bypassing 
> all the dataset stuff. Then you can interface to it as if it is a 
> private-wire machine. 
> 
> Let me know how it goes. 
> 
> Hope this helps, 
> 
> gil 
> 
> 
> 
> 
> At 07:42 PM 8/11/2004, you wrote: 
> >Hello Gil- 
> >Just wanted to let you know that my 33 arrived today in three boxes and 
> >appears to be in great condition with no shipping damage! Thanks to you 
> >for giving me the heads up and insisting that the seller spend extra time 
> >and effort in the packing process. My challenge at this point is trying to 
> >figure out how to get it back together, since I never took one apart 
> >before. The power supply is a separate unit with a molex connector and 
> >also has two clips that slip over something to support it. I think I have 
> >a manual someplace. Any comments would be appreciated. 
> >73 Bob Schaefer 
> >K6OSM since 1958 
> >Mccall, Idaho 
> 
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