Hi,
I am hoping to get some advice from someone who knows more about electrical sockets than me. Short version: what RJ-11 jack do I need to replace the one that the PC 5155 uses to connect the keyboard on the front panel?
Long version: My IBM PC 5155 had been giving progressively more frequent 301 keyboard errors on bootup. It works fine with two other XT capable switchable keyboards. I took the Model F XT keyboard apart to clean, look for corrosion or other problems, etc. That didn't help and the foam is in surprisingly great shape. Looked brand new inside. Wonderful build quality.
So then I got a multimeter from Amazon to do continuity testing and found that the problem was somewhere in the cabling. Pinouts at http://www.clickykeyboard.com/2013/apr13/012.jpg. The middle pin on the DIN ("data") is supposed to go to the white wire on the plug that connects to the keyboard PCB but there was no continuity. All the other pins tested fine.
Next challenge -- is the problem it the cable from the keyboard controller to the phone-style RJ-11 jack, or from the RJ-11 socket to the DIN that plugs into the regular XT motherboard connector. (If you want to know what I'm talking about look at this picture: http://www.clickykeyboard.com/2013/apr13/012.jpg. The RJ-11 connector at the top left is what the keyboard wire terminates in. To its right is the entire assembly that originally ran from an RJ-11 jack in the front panel around to a standard XT DIN connector at the rear. The picture shows the front panel trim that holds the jack as well as the jack itself.)
The pins in the RJ-11 did look a little bent, so I decided to remove it. There's a piece of trim at the front of the computer that holds what seems to be a standard RJ-11 jack in place with two very strong tabs. A cable runs down from the jack to a small hole in the bottom of the case, then around to the side and back to the DIN socket at the rear. That appears to allow for easy removal of the unclipped jack through the hole. Unfortunately the jack came apart when I was trying to free it.
Having pulled the remnant of the jack out through the base and freed the wires, I was able to confirm that one of the wires does connect fine to the middle pin on the DIN. Also, one of the pins on the phone-style connector has continuity with the white wire on the keyboard controller. So the problem was the now-defunct RJ11 jack failing to bring those wires into contact. It seems like the jack should a cheap thing to replace. Unfortunately I was stupid and did not photograph the jack before destroying it. And now I look for a replacement, I see there are many styles of RJ-11 jack for purchase and not all of them are likely to fit into the front panel piece that holds the jack in place.
I know I need 6 pins rather than the more common four. I see some jacks are called "6 position 4 connector" but as five out of six pins are used (no reset wire on my keyboard), I assume that I need to find a "6 position, 6 connector." So I think what I need is something like: https://www.zoro.com/leviton-rj-jack-and-module-jack-6p6c-usoc-la-41106-rt6/i/G4041905/. To fit optimally it should be not too deep and no wider in the back part than in the front part. For example, I think this one is too wide to fit. https://www.showmecables.com/icc-rj11-punchdown-keystone-jack-white
Then there's the question of how to get the existing wires into the new jack. It looks like the options are punchdown and toolless. I don't currently have a punchdown tool, but OTOH the tools are cheap enough. It seems like toolless tend to be a little longer and hence less likely to fit optimally in the existing clip.
So if anyone who knows RJ-11 jacks and/or the 5155 could take pity on me and give me a link to buy a jack that's likely to work I'd be very grateful.
A bonus would be if anyone knows which color wire on the cable from the DIN goes to which pin on the jack, as I (again stupidly) didn't photograph the old one and it used an old-school connector with two rows of connectors that doesn't match the new jacks anyway. But I can figure this out by contact tracing on the cable from the keyboard PCB to the RJ-11 connector and from the wires to the DIN plug, as I know the pinouts on each end.
Thanks for any help.
I am hoping to get some advice from someone who knows more about electrical sockets than me. Short version: what RJ-11 jack do I need to replace the one that the PC 5155 uses to connect the keyboard on the front panel?
Long version: My IBM PC 5155 had been giving progressively more frequent 301 keyboard errors on bootup. It works fine with two other XT capable switchable keyboards. I took the Model F XT keyboard apart to clean, look for corrosion or other problems, etc. That didn't help and the foam is in surprisingly great shape. Looked brand new inside. Wonderful build quality.
So then I got a multimeter from Amazon to do continuity testing and found that the problem was somewhere in the cabling. Pinouts at http://www.clickykeyboard.com/2013/apr13/012.jpg. The middle pin on the DIN ("data") is supposed to go to the white wire on the plug that connects to the keyboard PCB but there was no continuity. All the other pins tested fine.
Next challenge -- is the problem it the cable from the keyboard controller to the phone-style RJ-11 jack, or from the RJ-11 socket to the DIN that plugs into the regular XT motherboard connector. (If you want to know what I'm talking about look at this picture: http://www.clickykeyboard.com/2013/apr13/012.jpg. The RJ-11 connector at the top left is what the keyboard wire terminates in. To its right is the entire assembly that originally ran from an RJ-11 jack in the front panel around to a standard XT DIN connector at the rear. The picture shows the front panel trim that holds the jack as well as the jack itself.)
The pins in the RJ-11 did look a little bent, so I decided to remove it. There's a piece of trim at the front of the computer that holds what seems to be a standard RJ-11 jack in place with two very strong tabs. A cable runs down from the jack to a small hole in the bottom of the case, then around to the side and back to the DIN socket at the rear. That appears to allow for easy removal of the unclipped jack through the hole. Unfortunately the jack came apart when I was trying to free it.
Having pulled the remnant of the jack out through the base and freed the wires, I was able to confirm that one of the wires does connect fine to the middle pin on the DIN. Also, one of the pins on the phone-style connector has continuity with the white wire on the keyboard controller. So the problem was the now-defunct RJ11 jack failing to bring those wires into contact. It seems like the jack should a cheap thing to replace. Unfortunately I was stupid and did not photograph the jack before destroying it. And now I look for a replacement, I see there are many styles of RJ-11 jack for purchase and not all of them are likely to fit into the front panel piece that holds the jack in place.
I know I need 6 pins rather than the more common four. I see some jacks are called "6 position 4 connector" but as five out of six pins are used (no reset wire on my keyboard), I assume that I need to find a "6 position, 6 connector." So I think what I need is something like: https://www.zoro.com/leviton-rj-jack-and-module-jack-6p6c-usoc-la-41106-rt6/i/G4041905/. To fit optimally it should be not too deep and no wider in the back part than in the front part. For example, I think this one is too wide to fit. https://www.showmecables.com/icc-rj11-punchdown-keystone-jack-white
Then there's the question of how to get the existing wires into the new jack. It looks like the options are punchdown and toolless. I don't currently have a punchdown tool, but OTOH the tools are cheap enough. It seems like toolless tend to be a little longer and hence less likely to fit optimally in the existing clip.
So if anyone who knows RJ-11 jacks and/or the 5155 could take pity on me and give me a link to buy a jack that's likely to work I'd be very grateful.
A bonus would be if anyone knows which color wire on the cable from the DIN goes to which pin on the jack, as I (again stupidly) didn't photograph the old one and it used an old-school connector with two rows of connectors that doesn't match the new jacks anyway. But I can figure this out by contact tracing on the cable from the keyboard PCB to the RJ-11 connector and from the wires to the DIN plug, as I know the pinouts on each end.
Thanks for any help.