Author Topic: Need help wiring a KS-21276 connector in pay phone  (Read 3271 times)

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #45 on: June 15, 2017, 09:05:02 PM »
Okay. 

I have four terminals labeled top to bottom R (ring?), T (tip?), G (ground?), and L1.
Red wire to R, Green wire to T, Black wire and Yellow wire to G.

My multimeter says 53.4 volts across R and T.  This drops to 9.1 volts when the handset is lifted. 

I am hoping this is good data!   
It most certainly is.  The phone is "seizing" the line (going off hook electrically), which means we need to focus on the handset circuit. 

It would be good to know next whether the transmitter works and whether the dial generates tones when you dial. 

Find the screw terminals where the handset cord connects to the back of the dial unit inside the upper and with the handset off hook check for a low DC voltage across the RD and BK handset cord leads.  If there is DC there the transmitter is probably working.

If your meter has an OUTPUT mode and can measure AC with DC present, ignoring the DC, you can put it across T&R to detect presence of tones.  If there is no output mode or the meter reads the DC when no signal is present such as when the phone is on hook, place a 200V Mylar capacitor, value is not critical, 0.1uF is fine, in series with the meter to block the DC  If there is no OUTPUT mode use the 200mVAC or 2VAC setting, with the capacitor in series if the meter responds to the DC.  IIRC you're an electronics guy so measuring the presence of an AC signal superimposed on DC is probably old hat.

When you pick up the handset the meter should show the presence of Dial Tone.  When you dial a digit the level reading should increase while the key is pressed due to the louder Touch Tone signal.  When the key is released both the TT digit and DT should be gone and the meter should read zero.  When you push additional buttons the meter should show the TT digit level, a few hundred mV, while any key is pressed.

If the dial does not produce any tones but you detect DT while off hook swap the T&R connections to the phone.

Offline hydephone

  • *
  • Posts: 20
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #46 on: June 18, 2017, 08:47:47 PM »
Okay.  We have reached the end of my abilities.

I have electronics familiarity, can decipher a schematic, can solder, am comfortable populating a PCB (am trying to learn KiCad) but I am not a professional electrician.  I have never measured an AC signal superimposed on a DC voltage, don't know how to do that, don't have the tools for that, and am pretty sure I don't understand it.

I did, however, determine that there are about 23.4 volts between the red and black pins on the black squarish four pin modular connector that connects the handset cord to the dialing stuff.  The connector looks just like the modular connector in the item below.  The earpiece part of the handset is dead, dead, dead.  No sound. The microphone part works fine- when they call in other people can hear you speak "clear as a bell."

Could it be as simple as just needing a new handset?

http://www.payphone.com/Standard-Handset.html


   

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #47 on: June 18, 2017, 10:58:08 PM »
Okay.  We have reached the end of my abilities.

I have electronics familiarity, can decipher a schematic, can solder, am comfortable populating a PCB (am trying to learn KiCad) but I am not a professional electrician.  I have never measured an AC signal superimposed on a DC voltage, don't know how to do that, don't have the tools for that, and am pretty sure I don't understand it.

I did, however, determine that there are about 23.4 volts between the red and black pins on the black squarish four pin modular connector that connects the handset cord to the dialing stuff.  The connector looks just like the modular connector in the item below.  The earpiece part of the handset is dead, dead, dead.  No sound. The microphone part works fine- when they call in other people can hear you speak "clear as a bell."
OK.  I thought somehow that you did not have the ability to call it from another line.  Since you have done that you have demonstrated that the line and transmitter portions of the circuit work but the receiver circuit does not.  No need to make the measurements I mentioned. 

Understanding what I described would be good for your understanding of telephony and electronics in general but that's something you can grapple with at another time.

Was this 23.4V reading with the plug and socket mated or separated?  23.4V is a puzzlingly high voltage if they were mated.  I'm skeptical that this could possibly be correct.  If they were separated it's more reasonable, though still seems high.

What kind of meter did you use to arrive at this reading?

When you called it from another phone, besides the caller being able to hear, did you try pushing dial buttons on the payphone to see whether the caller can hear tones from the dial? 

If you try it and they don't hear tones, swap the line connections and try again.
Could it be as simple as just needing a new handset?

http://www.payphone.com/Standard-Handset.html
It could be but it would be very premature to replace the handset at this point.  It could also be the dial or any number of other problems including some wiring mistake

If my understanding is correct that you have a DMM or analog VOM, disconnect the spade tips for the receiver leads at TB2 in the dial unit.  These are normally two white handset cord leads but in your photo it looks like they might be white and green instead. I'd expect the two leads to be on terminals 7 & 8. 

Or if you can make contact with the leads towards the handset the way you did measuring transmitter voltage with the handset cord plug and socket disconnected from each other this time that would be okay too instead of disconnecting the spade tips from the screw terminals.

Put your meter on the lowest resistance range and measure the resistance of the receiver from the telephone set end of the handset cord.  You should get a reading of less than 200 ohms and you should hear a click in the receiver when the meter is connected and disconnected.  The click may be faint.

Another way to test the receiver itself and handset cord leads for it would be to momentarily parallel the receiver with the transmitter by connecting the spade tips from the receiver leads, which I think are WH and GN on your phone and probably on terminals 7 & 8, with the transmitter leads which we know have DC voltage across them.  I'd expect the transmitter leads to be on TB2 screws 3 & 6. 

If the receiver unit and receiver leads in the cord are good you will hear a click when taking the phone off hook and probably will also hear dial tone though not very loud.

Let us know...

Offline hydephone

  • *
  • Posts: 20
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #48 on: June 19, 2017, 12:10:54 AM »

I pulled the modular connector apart and measured between the two pins on the red and black.  All I knew to do. I just have a basic hobbyist multimeter.  This one https://www.amazon.com/SE-MM6162L-Digital-MultiMate-Display/dp/B0014JWTC8 in fact.

Didn't try pressing the buttons.  I'll try that and report.

Everything was working on the phone up until recently.  No one has opened it up since I put it up but me, so I really don't think anything has changed or become miswired.  It's much more likely some kid yanked on the handset and pulled something loose.  The disconnected wires I resoldered I think were just a product of time and environment.  Somebody abusing the handset is certainly possible with the environment.   

I'll try to work through poking about with 3&6 and 7&8. 

Thanks for staying with this for so long.

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #49 on: June 19, 2017, 12:31:56 AM »
I pulled the modular connector apart and measured between the two pins on the red and black.  All I knew to do. I just have a basic hobbyist multimeter.  This one https://www.amazon.com/SE-MM6162L-Digital-MultiMate-Display/dp/B0014JWTC8 in fact.

Didn't try pressing the buttons.  I'll try that and report.
What you did was fine.  The meter is perfectly adequate.
Everything was working on the phone up until recently.  No one has opened it up since I put it up but me, so I really don't think anything has changed or become miswired.  It's much more likely some kid yanked on the handset and pulled something loose.  The disconnected wires I resoldered I think were just a product of time and environment.  Somebody abusing the handset is certainly possible with the environment.   
Good.  We can rule out miswiring.  But I'm skeptical that the leads tore off the plug by themselves unless someone left the upper housing hanging by the connecting cord.  The original plug cap clamps the cable tightly so the leads never flex at the solder joints.  It would have required something much more than even a 7.0 magnitude earthquake to break those connections even if the phone came off the wall as a result and fell on the floor.

The handset cord is also very strong with a steel cable inside to provide tremendous tensile strength.  Not easy to break handset cord leads except through the leverage of twisting and you would see the effects of that on the outer sheath.  Receivers can be damaged by severe impacts but you probably would see the result of that as damage on the outside surface of the handset.

Dials are a common cause of problems.  There is also a muting circuit which is intended to prevent you from hearing coin deposit signals sent down the line when coins are dropped in.   Lots of complexity in single slot payphones.
I'll try to work through poking about with 3&6 and 7&8. 

Thanks for staying with this for so long.
OK, good!  You're welcome.  I'm not a believer in "shotgun" substitution of parts if the parts must be purchased.  If they are on hand, sure, then it makes sense.  But there are easier ways to localize the problem before ordering parts.  If you have a spare phone of any kind borrowing the receiver from that, even loose (not in a handset) would prove whether it's the receiver in the handset or something elsewhere in the phone's internal circuits.

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #50 on: June 19, 2017, 09:51:48 AM »
Another thought about this: When you check resistance of the receiver from the telephone set end of the handset cord with the plug and socket separated also check resistance towards the telephone set circuit to see whether it's a low resistance, open, or a short circuit (<5 ohms) both with the cradle switch up and with it down.  Also with it up and pushing buttons on the dial.

Offline hydephone

  • *
  • Posts: 20
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #51 on: June 20, 2017, 01:44:59 AM »
Okay good news-bad news I think.

Good news- When I call in, I can't hear them but they can hear me AND they can hear the key tones from the payphone keypad.  I didn't think of dialing a number "deaf" to see if it would go through, but I'm betting it would.

Bad news- I couldn't make heads or tails of the spade terminal set up.  The pins aren't continually numbered and I need more guidance.  With multiple pins of the same number I was very hesitant to start touching random stuff together.  Here is a picture of the best I could make of what pin is what.

Edit:  I know, it looks like I have three #2 pins, but that's what my notes say.  I'll double check it.

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #52 on: June 20, 2017, 03:41:05 PM »
Okay good news-bad news I think.

Good news- When I call in, I can't hear them but they can hear me AND they can hear the key tones from the payphone keypad.  I didn't think of dialing a number "deaf" to see if it would go through, but I'm betting it would.

Bad news- I couldn't make heads or tails of the spade terminal set up.  The pins aren't continually numbered and I need more guidance.  With multiple pins of the same number I was very hesitant to start touching random stuff together.  Here is a picture of the best I could make of what pin is what.

Edit:  I know, it looks like I have three #2 pins, but that's what my notes say.  I'll double check it.
The good news is more important than the bad news: something important works.  The bad news is easily overcome with more info.

It's been a long time since I've been inside my own single slot sets so I forgot that mine contain a "terminal map" (photo attached) to facilitate terminal ID without having to read the low contrast molded raised #s.

So the terminals in the 2nd row you construed as 2-4-8-8-13 are actually 12-14-8-8-13.  The others are correct.

The photo I attached is for a 61A dial unit wired for use in a 1C2 set so the lead colors you see in some cases will differ from what's in your 1D2.

You should now be able to proceed to test the receiver unit, receiver cord leads and receiver circuit towards the internal telephone set circuit as I described earlier with resistance measurements and by connecting the receiver in parallel with the transmitter as a temporary signal source.

I see the RD and BK transmitter leads on 3 and 6 respectively, where they belong.  I don't see any lead on 7 that looks like a handset cord lead.  It appears that there is a YL handset cord lead on 8 but it's hard to be certain since the image is cropped and does not show the surrounding area. 

Are the handset cord leads really RD, BK, GN and YL?  Is the GN lead on 4 along with the W dial lead?  That would bypass the receiver attenuating circuit causing very loud TouchTones in the handset during dialing before the phone stopped working.
« Last Edit: June 20, 2017, 04:34:03 PM by Alex G. Bell »

Offline hydephone

  • *
  • Posts: 20
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #53 on: June 25, 2017, 02:34:23 PM »
Sorry, I was out of town on business.  I am going over to test things now.

Edit:

Okay, I think we are at the limit of both my abilities and what can be done and diagnosed remotely.

I don't know what to do with the resistance task.  I think I am looking for 200 ohms resistance between a white and white or a white and white with green across 7 and 8 with the handset unplugged.  I have 2 7's and 2 8's.  Brown on one 8.  White and white with blue on one eight.  Am I looking for resistance across the two whites on 8?

The handset leads really are black, red, yellow, and green.  I am assuming red and black are the transmitter and yellow and green are the receiver.  Yellow goes direct to the non two white 8 pin.   Green goes to the lower four pin along with a white that disappears behind the board.  Red and black drop right to 3 and 6. 

It has been suggested to me that if I take a battery and energize the leads to the receiver in the earpiece I should hear a click/clicking.  If I do not, that suggests the earpiece is dead.    I THINK THINK THINK this is the same as "temporarily parallel the receiver with the transmitter by connecting 3 and 6 with a DC voltage to 7 and 8".  Multiple pins, multiple wires confusing.  I don't know.  So I took a battery pack at 3 volts across the yellow and green from the handset and heard nothing.  No clicks no nothing.  Transmitter works.  Dial pad tones work. Accepts incoming calls. You get a busy signal if it is off hook. 

I am under a little time pressure now to get this fixed ("is it done yet?"), so I think I am going to take the shotgun shot in the dark approach and order a new handset. 
« Last Edit: June 25, 2017, 03:51:23 PM by hydephone »

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #54 on: June 27, 2017, 12:05:11 PM »
Sorry, I was out of town on business.  I am going over to test things now.

Edit:

Okay, I think we are at the limit of both my abilities and what can be done and diagnosed remotely.

I don't know what to do with the resistance task.  I think I am looking for 200 ohms resistance between a white and white or a white and white with green across 7 and 8 with the handset unplugged.  I have 2 7's and 2 8's.  Brown on one 8.  White and white with blue on one eight.  Am I looking for resistance across the two whites on 8?

The handset leads really are black, red, yellow, and green.  I am assuming red and black are the transmitter and yellow and green are the receiver.  Yellow goes direct to the non two white 8 pin.   Green goes to the lower four pin along with a white that disappears behind the board.  Red and black drop right to 3 and 6. 

It has been suggested to me that if I take a battery and energize the leads to the receiver in the earpiece I should hear a click/clicking.  If I do not, that suggests the earpiece is dead.    I THINK THINK THINK this is the same as "temporarily parallel the receiver with the transmitter by connecting 3 and 6 with a DC voltage to 7 and 8".  Multiple pins, multiple wires confusing.  I don't know.  So I took a battery pack at 3 volts across the yellow and green from the handset and heard nothing.  No clicks no nothing.  Transmitter works.  Dial pad tones work. Accepts incoming calls. You get a busy signal if it is off hook. 

I am under a little time pressure now to get this fixed ("is it done yet?"), so I think I am going to take the shotgun shot in the dark approach and order a new handset.
It appears to me that you need to re-read what I stated below.  It seems to me you misunderstood a number of points. 

Among them, you are looking the measure the resistance to determine its value, which normally would be an unknown value below 200 ohms, not equal to 200 ohms.  Another: all terminals with the same numerical designation are internally connected together.  The resistance between them will always be near zero (less than one ohm).

Placing a battery across the receiver leads would be another way to test the receiver IF you actually are working with the receiver leads.  I'm not sure you are from what you stated above, which seems to indicate some confusion.  Also this would only be a valid test if there is no short circuit within the phone's internal circuit.  That's why I instructed you to disconnect the receiver leads, which would eliminate a short towards the internal circuits, and connect them across the transmitter where it's been demonstrated there is DC present.

There's no need to speculate about the handset lead colors.  Although what they are may not be clear to others from a photo, the phone is in front of you therefore you can trace the leads coming out of the handset cord and determine the lead colors with absolute certainty.

Please let us know the results from connecting the replacement handset.

Offline hydephone

  • *
  • Posts: 20
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #55 on: July 03, 2017, 05:52:24 PM »
Okay.  New handset arrived.

Went over, plugged it in. With the old handset, they could hear you, you couldn't hear them. Transmitter, no receiver.

With the new handset, you could hear them, they couldn't hear you. Receiver, no transmitter.

Crap, I said out loud.

The green and black on the new and old looked the same, but the red and yellow were switched.  Okay, so I switched the spade terminals on the board thinking that might do it. Nothing, No sound at all.

Double crap.

Neighbor says, what if we just turn it and before I could do anything plugs it back in after giving it a quarter turn.  I'm thinking this is going to short it out, not going to work, going to automatically call 911 on repeat, something. 

Nope.

The phone works. Outgoing, incoming, hear this, hear that.

Closed it back up and walked away.

Thanks for all the help.  Thanks Alex G.  I learned a little bit!

 

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #56 on: July 03, 2017, 06:08:16 PM »
Okay.  New handset arrived.

Went over, plugged it in. With the old handset, they could hear you, you couldn't hear them. Transmitter, no receiver.

With the new handset, you could hear them, they couldn't hear you. Receiver, no transmitter.

Crap, I said out loud.

The green and black on the new and old looked the same, but the red and yellow were switched.  Okay, so I switched the spade terminals on the board thinking that might do it. Nothing, No sound at all.

Double crap.

Neighbor says, what if we just turn it and before I could do anything plugs it back in after giving it a quarter turn.  I'm thinking this is going to short it out, not going to work, going to automatically call 911 on repeat, something. 

Nope.

The phone works. Outgoing, incoming, hear this, hear that.

Closed it back up and walked away.

Thanks for all the help.  Thanks Alex G.  I learned a little bit!
Congratulations!  You're welcome. 

But now it's your turn to teach me!   ;D  Turned what a quarter turn???

Offline hydephone

  • *
  • Posts: 20
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #57 on: July 03, 2017, 11:16:09 PM »
The square black modular connector.  I'll have to go back over and look at it again but I don't think it is r to r, b to b, y to y and g to g. It is some other way, but it worked.  I'll take a pic tomorrow and post it. .   

Alex G. Bell

  • Guest
Re: Need help wiring a KS-21276 connector in pay phone
« Reply #58 on: July 03, 2017, 11:29:53 PM »
The square black modular connector.  I'll have to go back over and look at it again but I don't think it is r to r, b to b, y to y and g to g. It is some other way, but it worked.  I'll take a pic tomorrow and post it. .
That's puzzling! 

Is there a loud click in the receiver when you depress the lever in the center of the handset cradle to hang up? 

Are the TouchTone sounds in the receiver during dialing at a comfortable level like before it failed, very loud or absent?