With the 5150 and 5160 XT and be able to put EGA out of the DB9 connector not the VGA and I have tried this one: https://stason.org/TULARC/pc/graphics-cards/A … -VGA-1515C.html and all I get is a Horizontal line that looks like a sync issue or something.
Here is a picture of the one I have:
Hi there! Is the dip switch block configured accordingly?
It's crucial for the monitor and video modes available.
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
//My video channel//
Jo22 wrote on 2022-12-02, 16:47:Hi there! Is the dip switch block configured accordingly?
It's crucial for the monitor and video modes available.
Yeah I tried every dip switch combination that is listed on that https://stason.org/TULARC/pc/graphics-cards/A … -VGA-1515C.html and I can only seem to get CGA to work over the Db9 connector not EGA and the EGA does work through the VGA connector on there but with a VGA monitor.
Are you sure your monitor is designed to supports the EGA resolution? Are you sure the EGA resolution support (IBM called it "Mode 2") of your monitor is not broken? In case you are using something like the RetroTink, did you select the proper profile?
mkarcher wrote on 2022-12-02, 17:43:Are you sure your monitor is designed to supports the EGA resolution? Are you sure the EGA resolution support (IBM called it "Mode 2") of your monitor is not broken? In case you are using something like the RetroTink, did you select the proper profile?
Yes I am sure it is an IBM 5154 EGA Monitor and i know it is not broken because I used it with my 5170AT which has a VIDEO 7 D2A62LVGA EGA card in it and the Monitor works fine.
thegenerallee86 wrote on 2022-12-02, 16:53:Jo22 wrote on 2022-12-02, 16:47:Hi there! Is the dip switch block configured accordingly?
It's crucial for the monitor and video modes available.Yeah I tried every dip switch combination that is listed on that https://stason.org/TULARC/pc/graphics-cards/A … -VGA-1515C.html and I can only seem to get CGA to work over the Db9 connector not EGA and the EGA does work through the VGA connector on there but with a VGA monitor.
My bad, I didn't know that. 🙁
Hm.. You could try inverting the setting for EGA.
Maybe ON/OFF are labeled the wrong way, not sure. 🤷♂️
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
//My video channel//
Jo22 wrote on 2022-12-02, 18:17:My bad, I didn't know that. 🙁 Hm.. You could try inverting the setting for EGA. Maybe ON/OFF are labeled the wrong way, not sure […]
thegenerallee86 wrote on 2022-12-02, 16:53:Jo22 wrote on 2022-12-02, 16:47:Hi there! Is the dip switch block configured accordingly?
It's crucial for the monitor and video modes available.Yeah I tried every dip switch combination that is listed on that https://stason.org/TULARC/pc/graphics-cards/A … -VGA-1515C.html and I can only seem to get CGA to work over the Db9 connector not EGA and the EGA does work through the VGA connector on there but with a VGA monitor.
My bad, I didn't know that. 🙁
Hm.. You could try inverting the setting for EGA.
Maybe ON/OFF are labeled the wrong way, not sure. 🤷♂️
That's ok and yeah I have tried that and no luck either.
Here is an image of what it is doing: https://scontent-bos5-1.xx.fbcdn.net/v/t39.30 … l6g&oe=638F860D
The picture looks like the monitor is unable to capture the horizontal sync frequency. The EGA text mode is supposed to run in mode 2 (350 scan lines) at 21.4kHz horizontal rate. Either the card fails to signal "mode 2" to the monitor, or the timing isn't close enough to actual EGA timing. According to the SAMS PhotoFacts for the IBM 5154, the "horizontal hold" pot is called "horizontal frequency 2" for "mode 2", which is the potentiometer RT102 at the corner of the main board. If the horizontal timing of the Oak card is just slightly off, you might get away with adjusting the horizontal oscillator.
mkarcher wrote on 2022-12-02, 19:39:The picture looks like the monitor is unable to capture the horizontal sync frequency. The EGA text mode is supposed to run in mode 2 (350 scan lines) at 21.4kHz horizontal rate. Either the card fails to signal "mode 2" to the monitor, or the timing isn't close enough to actual EGA timing. According to the SAMS PhotoFacts for the IBM 5154, the "horizontal hold" pot is called "horizontal frequency 2" for "mode 2", which is the potentiometer RT102 at the corner of the main board. If the horizontal timing of the Oak card is just slightly off, you might get away with adjusting the horizontal oscillator.
Would that be the Horizontal 1 and Horizontal 2 that are on the back of the monitor inside near the Vertical 1 and Vertical 2 that stick out of the back of the case of the monitor?
thegenerallee86 wrote on 2022-12-02, 20:20:Would that be the Horizontal 1 and Horizontal 2 that are on the back of the monitor inside near the Vertical 1 and Vertical 2 that stick out of the back of the case of the monitor?
I'm afraid, no. Those controls are RT401 and RT402 for the horizontal width of the picture. The basic tuning of the horizontal oscillators (one for CGA modes, one for EGA modes) are on a different corner of the same PCB. The are called RT101 and RT102. They are located near the lower left corner of the front of the monitor. If you happen to have a scope (or know someone with a scope), you should verify that the horizontal frequency is indeed around 21.8kHz before trying to adjust the monitor. I was wrong writing 21.4 earlier. -0° has a scope screenshot of the correct EGA horizontal sync pulse. They also show the required vertical sync pulse to select mode 2. It's important the the vertical signal is normally high, whereas the horizontal signal is normally low.
mkarcher wrote on 2022-12-02, 20:54:thegenerallee86 wrote on 2022-12-02, 20:20:Would that be the Horizontal 1 and Horizontal 2 that are on the back of the monitor inside near the Vertical 1 and Vertical 2 that stick out of the back of the case of the monitor?
I'm afraid, no. Those controls are RT401 and RT402 for the horizontal width of the picture. The basic tuning of the horizontal oscillators (one for CGA modes, one for EGA modes) are on a different corner of the same PCB. The are called RT101 and RT102. They are located near the lower left corner of the front of the monitor. If you happen to have a scope (or know someone with a scope), you should verify that the horizontal frequency is indeed around 21.8kHz before trying to adjust the monitor. I was wrong writing 21.4 earlier. -0° has a scope screenshot of the correct EGA horizontal sync pulse. They also show the required vertical sync pulse to select mode 2. It's important the the vertical signal is normally high, whereas the horizontal signal is normally low.
I do have an oscilloscope and also checked the Video card and noticed near the oscillators that one of the resistors near the last one closest to the Dip switches is low at 6k and the rest are all at 10k.
thegenerallee86 wrote on 2022-12-02, 21:04:I do have an oscilloscope and also checked the Video card and noticed near the oscillators that one of the resistors near the last one closest to the Dip switches is low at 6k and the rest are all at 10k.
The resistor value is unlikely to be an issue. Generally, this resistor is used for DC biasing of the oscillator circuit, and the higher the frequency of the oscillation, the lower resistor value is chosen in an otherwise similar circuit. The ultra-low-power 32kHz oscillators for the real-time clock and wrist-watches often use 1MOhm or even higher at that point. My guess is that the 6k resistor is next to a 36MHz crystal used for 800x600, and 10k is located next to the other three crystals, likely 16.257 or 16.000 for EGA, and 25.175 MHz as well as 28.322 MHz for VGA modes. CGA modes at CGA timing are likely generated by dividing the 28.322 frequency by two inside the OAK chip, so you get 14.161. A proper CGA used a pixel clock of 14.318, which is close enough. If your card doesn't have a 16.257 MHz (or 16.000 MHz) oscillator, it wouldn't be surprising that the EGA timings are off.
mkarcher wrote on 2022-12-03, 17:13:thegenerallee86 wrote on 2022-12-02, 21:04:I do have an oscilloscope and also checked the Video card and noticed near the oscillators that one of the resistors near the last one closest to the Dip switches is low at 6k and the rest are all at 10k.
The resistor value is unlikely to be an issue. Generally, this resistor is used for DC biasing of the oscillator circuit, and the higher the frequency of the oscillation, the lower resistor value is chosen in an otherwise similar circuit. The ultra-low-power 32kHz oscillators for the real-time clock and wrist-watches often use 1MOhm or even higher at that point. My guess is that the 6k resistor is next to a 36MHz crystal used for 800x600, and 10k is located next to the other three crystals, likely 16.257 or 16.000 for EGA, and 25.175 MHz as well as 28.322 MHz for VGA modes. CGA modes at CGA timing are likely generated by dividing the 28.322 frequency by two inside the OAK chip, so you get 14.161. A proper CGA used a pixel clock of 14.318, which is close enough. If your card doesn't have a 16.257 MHz (or 16.000 MHz) oscillator, it wouldn't be surprising that the EGA timings are off.
Yeah I definitely don't see one on there but I'll double check anyways.
