[GreenKeys] #2500 Telephone Sets

[wa2hwj at att.net]

I am aware of the reversed polarity issue, but I recall a lot
of earlier TT phones would go "mushy" (so would the
dials on the 33 TWX machines, for that matter). I wonder if it was just
dirty contacts, as Don has pointed out?  But I do remember trying
to clean the contacts with no improvement. Of course, us Hams
who used the dials in the earlier days to use on autopatches, etc.,
probably destroyed them with wrong voltages, etc. My
1A2 Card Dialer phone and the card dialer in my 35ASR both
work fine....!

Jack WA2HWJ

NNNN



-------------- Original message from Sheldon Daitch <sdaitch at ibb.gov>: -------------- 


> Well, I can think of three or four reasons. 
> 
> Assuming it is working mechanically, it could be: 
> 
> dirty switch contacts 
> 
> one or more transistors are defective (I just can't remember 
> how many there are on the old DTMF pads - maybe it 
> was only one transistor - write only memory time, I think) 
> 
> Open coil(s) 
> 
> other defective component 
> 
> (I can't easily find a schematic for the old style DTMF pads 
> so I can't tell you what other parts there might be - all my 
> phone literature is at home!) 
> 
> Last but not least, if the phone/pad combination is old enough, 
> remember the early phones were polarity sensitive, so if the 
> phone loop polarity is reversed, the pad won't work. I'd try 
> changing the polarity of the phone line before working on 
> anything else. 
> 
> 
> Hope this helps, 
> 
> 73 
> Sheldon 
> WA4MZZ 
> 
> 
> 
> 
> 
> wa2hwj at att.net wrote: 
> 
> > Has anyone ever figured out why the old Touchtone dials go bad? 
> > 
> > Jack WA2HWJ 
> > 
> > -------------- Original message from Roy Morgan : 
> -------------- 
> > 
> > > At 11:41 AM 1/4/2006, Steve Hilsz wrote: 
> > > >... See www dot navysalvage dot com for more details on repairs to older 
> > > >telephones. 
> > > 
> > > Steve, 
> > > 
> > > Thanks for that link. I followed it and found details on princess phones, 
> > > some of which I have and want to get running again. 
> > > 
> > > ALSO: I found details on switchboard lamps - these are the long thin things 
> > > found in some telephone/teletype patch panels. I'm very happy to now know 
> > > the voltage of a few such lamps I have here. 
> > > 
> > > Roy 
> > > 
> > > 
> > > - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing! 
> > > 7130 Panorama Drive, Derwood MD 20855 
> > > Home: 301-330-8828 Cell 301-928-7794 
> > > Work: Voice: 301-975-3254, Fax: 301-948-6213 
> > > roy.morgan at nist.gov -- 
> > > 
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