GW202 I/O card problem \ VOGONS

GW202 I/O card problem

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First post, by MaLLy_R

Posted on 2024-02-20, 13:40

MaLLy_R Offline

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Hello there... Great Vogons.
I own "PERIPHERALS ENTERPRISE COMPANY GW202".
http://mally.tim.com.pl/8bit_isa/MULTI_ ... 2_1(&).jpg
Card seems to work so I wanted to expand it with second COM.
I added missing chips (tested, working) and set jumpers according to instructions:
(https://www.minuszerodegrees.net/manuals/GW20 … rs%20Manual.pdf)
Bios sees COM2 but devices connected to it are not working.
What could be the problem? I already tested connections between pin header and 188 and 189 chips, they seems to be similar to COM1.
I'm sure 8250 is working, i tested it i another card.
Also when I pull-out 8250 from socked COM2 is no longer active in BIOS, so there is some kind of communication.

Can any one know what is the issue?

Last edited by MaLLy_R on 2024-05-29, 13:48. Edited 2 times in total.

MIDI. I like MIDI... A lot! (Also stuck in 8bit PC era)

Reply 1 of 8, by weedeewee

Posted on 2024-02-20, 17:13

weedeewee Offline

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Is the IRQ properly set? com2 normally uses irq 3, while com1 is on irq4

try a loopback, connect pins 2 & 3 together, open a terminal, type, anything you type should be echoed back to you (without local echo being on in the terminal)
If that does not work you'll have to dig deeper.
figure out if the interrupt gets triggered, loopback the 8250, maybe the 188 or 189 chips are faulty...

oh yeah and check the serial port link in my signature.

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 2 of 8, by MaLLy_R

Posted on 2024-02-20, 20:53

MaLLy_R Offline

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weedeewee wrote on 2024-02-20, 17:13:

Is the IRQ properly set? com2 normally uses irq 3, while com1 is on irq4

IRQ is set properly, to 3. (COM1 is set to IRQ 4)
Once, to be sure I disabled COM1, it didn't help.

weedeewee wrote on 2024-02-20, 17:13:
maybe the 188 or 189 chips are faulty...

Both are tested and they work in other card. Besides I tried several sets of those two chips.

MIDI. I like MIDI... A lot! (Also stuck in 8bit PC era)

Reply 3 of 8, by MaLLy_R

Posted on 2024-03-13, 10:44

MaLLy_R Offline

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I tried 3 known working 8250 chips, and 6 also known working 188 and 189 chips... any suggestions?

MIDI. I like MIDI... A lot! (Also stuck in 8bit PC era)

Reply 4 of 8, by weedeewee

Posted on 2024-03-13, 16:39

weedeewee Offline

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? why did I forget to ask about the voltages.

do you have all the voltages? +12v, +5v, -5v, -12v (actually only +12v & -&12v should be checked for the serial port)
without +5v the pc wouldn't be booting, and -5v meh.

verify you have'm on the psu, & on the io card. datasheet for the 188 or 189 chips should tell you were to measure.

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 5 of 8, by MaLLy_R

Posted on 2024-04-05, 14:00

MaLLy_R Offline

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weedeewee wrote on 2024-03-13, 16:39:
? why did I forget to ask about the voltages. […]
Show full quote

? why did I forget to ask about the voltages.

do you have all the voltages? +12v, +5v, -5v, -12v (actually only +12v & -&12v should be checked for the serial port)
without +5v the pc wouldn't be booting, and -5v meh.

verify you have'm on the psu, & on the io card. datasheet for the 188 or 189 chips should tell you were to measure.

First COM port is working just fine, so i don't think its voltages problem.
Funny thing is that i acquired second, same card, and this one works perfectly on the same chips. So it is not factory/design error.
(tested on same mobo, same psu, same chips)

MIDI. I like MIDI... A lot! (Also stuck in 8bit PC era)

Reply 6 of 8, by weedeewee

Posted on 2024-04-05, 14:02

weedeewee Offline

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are the added 188 189 chips verified working ?

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

Reply 7 of 8, by MaLLy_R

Posted on 2024-04-05, 14:23

MaLLy_R Offline

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weedeewee wrote on 2024-04-05, 14:02:

are the added 188 189 chips verified working ?

Yes, they are working.

http://mally.tim.com.pl/8bit_isa/MULTI_ ... 2_1(&).jpg doesn't work (COM2)
http://mally.tim.com.pl/8bit_isa/MULTI_PERIPH … ANY_GW202_2.jpg works just fine
Same chips, same mobo, sme psu.

MIDI. I like MIDI... A lot! (Also stuck in 8bit PC era)

Reply 8 of 8, by weedeewee

Posted on 2024-05-29, 14:32

weedeewee Offline

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Then there's no other option than that it has to be a board problem, either a cut trace, bad solderjoint, bad logicchip, ... on the multi io card where com2 isn't working.

Right to repair is fundamental. You own it, you're allowed to fix it.
How To Ask Questions The Smart Way
Do not ask Why !
https://www.vogonswiki.com/index.php/Serial_port

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