Bad ps/2 port ?

[Mathwiz]

But yes, apparently the keyboard itself in this case is failing or maybe the batteries are bad or contacts are rusty.

Batteries? D'oh! That should have been the first thing we suggested.

 

All this discussion and nobody else (including me) thought to mention the obvious, but better late than never.

[Drugwash]

Yeah, we often assume people know the basics but sometimes they don't.

Other times it's much more complicated although it appears to be extremely simple.

Go figure!

[submix8c]

(Heh...) My bad...

http://www.msfn.org/board/topic/174284-bad-ps2-port/#entry1106086

[MiKl]

USB->PS2 adapter is simply a "rewire" of the connection. There's also PS2->USB so I doubt this is a problem. Driver is irrelevant in your case. The keyboard (from the tests you've shown) indicate that it's a deader. Time for a replacement.

 

O.K. but what are the odds that two sets of the same keyboard are dying at the very same day although one of it was actually seldom used because it was meant as a backup ??

Batteries were tested/replaced during the tests, of course. The Logitech driver/software would have given an alarm anyway long before the batteries were too empty.

I also tried going back to the original nvcore.vxd (82.69) but this did not helped either.

 

Well, since other keyboards are working I also think that something must be causing an frequency interference for this particular model. Will try to get other combo(s) from Ebay later this week and report back asap.

[submix8c]

Ummm, my *last* post was to correct my error. Did you see the post that said

PS/2 works through +Vcc, GND, CLK, Data while USB works through +Vcc, GND, Data+, Data-. There has to be an active conversion of the signals, otherwise why bother to designate different sockets for same signals!?

But yes, apparently the keyboard itself in this case is failing or maybe the batteries are bad or contacts are rusty.

You said

what are the odds that two sets of the same keyboard are dying at the very same day

You're saying they *did* work but now don't, right?

1) Office/work room. Here occured this problem. Right now I have a 'Logitech cordless keyboard' connected to the PC and it is working perfectly so I think there are no hardware problems in this machine.

It seems that your problem is with the Living Room PC itself.

[Drugwash]

Mikl, to rule out the possibility for the PS/2 port itself to be defective you should connect and test a true PS/2 keyboard.

In fact you should always have one in the house - as a backup, for testing purposes, whatever.

 

There may be other subtle issues that have not been mentioned:

- BIOS behaving inconsistently due to (partial) incompatibility with the USB-to-PS/2 adapter, occasionally leading to faulty detection of the keyboard.

- Loose contacts in either the motherboard PS/2 socket or the adapter's internals.

- Voltage variations (or constant over/under-power) at the PS/2 port that affect either the adapter, the receiver or both.

- Recent replacement or installation of home appliances that may produce radio interference (anything with wireless capabilities).

- Outdoor installation of powerful wireless equipment near to your house/apartment.

- The keyboards themselves having been programmed to self-destruct after a designated period of time.

 

Anybody else please feel free to chime in with other possible reasons for that hardware setup to fail according to the description.

[MiKl]

Hi Drugwash, thank you very much that you are actually reading my postings !!!!

 

I agree that having a wired, real ps/2-keyboard would be ideal in this situation but I think since other keyboard-models in various combinations of keyboard and receiver (including the receiver that otherwise might have been the cause of the problem) are working absolutely fine on BOTH machines - an outdoor radio interference is the most likely reason for this issue with the 'Logitech cordless desktop Express'-keyboard.

[Drugwash]

Just trying to help when/if possible.

 

Thinking deeper, a radio interference would most likely disturb reception with any other keyboard brand/model since the band allocated for bluetooth communications is essentially the same.

Therefore I'd be inclined to believe that particular keyboard model/series may have a design fault (uneven pressure on PCB breaking or unsoldering connections/terminals) or may employ low quality components that changed characteristics in time (such as bad capacitors that dried out, out-of-specs quartz oscillator, bad silicon chip, bad silicon connector between keyboard foils and PCB and so on).

 

If I were you, just out of curiosity I'd carefully dismantle the apparently dead keyboard looking for any visible signs of failure: tiny cracks in the PCB, oxidated contacts for batteries or at the foils+PCB contact zone, eroded tracks on the foils etc.

 

I haven't dismantled such wireless keyboard before so I don't know how the transmitter block looks like but there may be something to look for in there too if it's not completely sealed - just don't move/bend components in there (especially coils, if any).

 

Just don't blame me if you break anything.

[submix8c]

El-cheapo PS/2 Keyboard in any thrift store (e.g. Goodwill) in the USA - $2USD or less. It would behoove you to purchase one to eliminate the possibility of a bad port *and* to have a spare.

 

You seem to be burning a lot of time on this without fully testing (i.e. with a true PS/2).