Problems with detecting keyboard on socket 7 motherboard \ VOGONS

Problems with detecting keyboard on socket 7 motherboard

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First post, by ksiumaxx

Posted on 2023-04-25, 13:12

ksiumaxx Offline

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Hi. I have a PCPartner MB520NH motherboard which I would really want to use for my dos pc, but it's not detecting any keyboard I try. Din5, PS2->Din5 adapter failed, even tho all of the keyboards I tried are working, and get detected on other systems. When I boot the pc, lights on the keyboard don't flash once like they should, and it shows on the screen Keyboard error or no keyboard present. I saw this Keyboard error or no keyboard present post where they mentioned about a keylock jumper on the board, but I couldn't find any mention about it in the manual. The also mentioned about a keyboard fuse, which should be somewhere near the keyboard connector, but I wasn't able to locate it.
And I also have a question, which I couldn't find answer for even tho it could make using this motherboard much easier for me. If I would be able to make keyboards work again, could it be possible to replace Din5 connector with PS/2? I know I can just use a simple adapter, but adapters like that are not using any electronics, only wires so it should be doable.

Here you can find a manual and some specification about the motherboard: https://theretroweb.com/motherboards/s/pcpart … 20-03#downloads

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Reply 1 of 24, by bogdanpaulb

Posted on 2023-04-25, 14:54

bogdanpaulb Offline

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You can check with a multi meter the presence of +5v on the DIN5 connector on the selected pin.
The location of the KB lock connector it's in the manual, and is shown in the second picture.

Reply 2 of 24, by ksiumaxx

Posted on 2023-04-25, 15:13

ksiumaxx Offline

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So I tested it with a multimeter, and I got 0.8V. I dont't know if I was doing it ok, but it was the only pin multimeter showed anything

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Reply 3 of 24, by bogdanpaulb

Posted on 2023-04-25, 15:35

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Can you confirm: motherboard was turned on, multimeter was set on continuous voltage (e.g. 20v dc) and you used ground for the second lead of the multimeter ?

Reply 4 of 24, by Repo Man11

Posted on 2023-04-25, 16:22

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When looking at the back of the motherboard you ought to be able to follow the trace from the DIN connector to the keyboard fuse. I have a PCChips M520 where the issue was a bad solder joint on the keyboard fuse and the solder joints for the DIN connector were cracked.

After watching many YouTube videos about older computer hardware, YouTube began recommending videos about trains - are they trying to tell me something?

Reply 5 of 24, by ksiumaxx

Posted on 2023-04-25, 16:27

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bogdanpaulb wrote on 2023-04-25, 15:35:

Can you confirm: motherboard was turned on, multimeter was set on continuous voltage (e.g. 20v dc) and you used ground for the second lead of the multimeter ?

Yes

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Reply 6 of 24, by bogdanpaulb

Posted on 2023-04-25, 16:32

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ksiumaxx wrote on 2023-04-25, 16:27:

bogdanpaulb wrote on 2023-04-25, 15:35:

Can you confirm: motherboard was turned on, multimeter was set on continuous voltage (e.g. 20v dc) and you used ground for the second lead of the multimeter ?

Yes

Can you post a picture with the area from the first picture (DIN5 connector area) front and back of your motherboard ?

Reply 7 of 24, by ksiumaxx

Posted on 2023-04-25, 16:45

ksiumaxx Offline

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bogdanpaulb wrote on 2023-04-25, 16:32:

ksiumaxx wrote on 2023-04-25, 16:27:

bogdanpaulb wrote on 2023-04-25, 15:35:

Can you confirm: motherboard was turned on, multimeter was set on continuous voltage (e.g. 20v dc) and you used ground for the second lead of the multimeter ?

Yes

Can you post a picture with the area from the first picture (DIN5 connector area) front and back of your motherboard ?

The attachment IMG_20230425_183905.jpg is no longer available

The attachment IMG_20230425_183915.jpg is no longer available

The attachment IMG_20230425_183951.jpg is no longer available

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Reply 8 of 24, by bogdanpaulb

Posted on 2023-04-25, 16:56

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With power on, check with a multimeter the presence of 5v dc at all the points marked, careful not to short anything.

Reply 9 of 24, by ksiumaxx

Posted on 2023-04-25, 17:15

ksiumaxx Offline

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So yeah my multimetemer wasn't in the correct mode. The Din connector isn't getting 5V on any of the pins, and the ones you marked got:
1. 5.10V
2. 5.10V
3. 5.11V
4. Top one got 5.10V and bottom got 0.69V

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Reply 10 of 24, by bogdanpaulb

Posted on 2023-04-25, 17:56

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Again, just to be sure, what was the voltage on the pins of the 'black' component ? Because you gave 2 values for nr.4.

Last edited by bogdanpaulb on 2023-04-25, 18:04. Edited 1 time in total.

Reply 11 of 24, by ksiumaxx

Posted on 2023-04-25, 18:03

ksiumaxx Offline

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bogdanpaulb wrote on 2023-04-25, 17:56:

Again, just to be sure, what was the voltage on that pin of the 'black' component ? Because you gave 2 values for nr.4.

Becouse you marked 2 sides of the black thing before. The one you marked now got 5.10V

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Reply 12 of 24, by bogdanpaulb

Posted on 2023-04-25, 18:04

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And the other has 0.69?

Reply 13 of 24, by ksiumaxx

Posted on 2023-04-25, 18:07

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Yes

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Reply 14 of 24, by bogdanpaulb

Posted on 2023-04-25, 18:09

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Do you have soldering equipment?

Reply 15 of 24, by ksiumaxx

Posted on 2023-04-25, 18:11

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Yes, but I'm not very good at soldering. But if it's not anything too hard I should be able to do it.

Last edited by ksiumaxx on 2023-04-25, 18:15. Edited 1 time in total.

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Reply 16 of 24, by bogdanpaulb

Posted on 2023-04-25, 18:15

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Do you have any defective boards from that era (or any at all) to to take that fuse from?

Reply 17 of 24, by ksiumaxx

Posted on 2023-04-25, 18:16

ksiumaxx Offline

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Yes. And I have a lot od them from around 1995-2005

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Reply 18 of 24, by bogdanpaulb

Posted on 2023-04-25, 18:26

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Then search on the scrap/dead ones for a fuse and replace it ( the black component ). You should be able to find it in the same area of the motherboard, just post some pictures of what you found so you will not use a ferrite bead instead (they look very similar, the other 'black' component with pins 1 and 2).

Reply 19 of 24, by ksiumaxx

Posted on 2023-04-25, 18:30

ksiumaxx Offline

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Ok, I'll look and send a picture if I found one. But wouldn't it be easier to just buy one new? And does it have to be an AT board to steal fuse from. I lack AT boards, but have a lot of ATX ones.

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