GrandVimage Nubus Graphiccard Video problems ...

[franklyn]

The video output is faulty. I'm not sure if it's a hardware or software issue? If I play around with the control panel and change settings, then restart, it suddenly works fine. Then the next time I start it, it malfunctions again.

Apple Quadra700 running at 32 MHz and GrandVimage control panel 1.3.1b or 1.4.1b2. There's no difference. I'm using the maximum resolution of 1024x768 with 16.7M colors.

 

[MJ313]

Might want to replace that 30+ year old electrolytic cap on there. I'm not familiar with the card or this issue, but that's probably a normal thing to take care of at this point.

 

[franklyn]

Yes I think so too, it is a 220u/4V one. All other are Tantal.

 

[franklyn]

220uF/4V connect to Pin 43 of the Bt473PKJ is Vref and GND ...

I wanted to desolder the old one and measure it, but that didn't work, so I had to unscrew it. I ordered a new one, but I quickly soldered in a 220uF/25V capacitor in.

The malfunction didn't change, though ...!

All solder are very good. There are only one Ram chip that is a other Typ as the other ones.


Any Idea whats the Problem?

 

[franklyn]

Monitor Signal is faulty but the Screenshot is ok ...

 

[zigzagjoe]

The single different type of VRAM chip is common on grandvimage cards. Not sure why they do that.

Just checking, are you using a monitor known to support sync on green or have you tried different monitors? Same on the choice of adapter. Depending on the monitor selection in the CP iirc it will use different types syncs according to the type selected. The generic multisync options are going to be the ones you want.

 

[franklyn]

The Monitor is ok it is a NEC MultiSync LCD1970NX. It is good with the Quadra Onboard Video, a Performa 475 and a IIsi with a Radius Graphiccard. I can test a iiyama LCD Monitor ...


I'm pretty sure it's a software issue. If the image is fine and I switch from the default 1024x768 to 832x624 with the same color depth via the monitor and sound control panel, the image is immediately corrupted again.

The phenomenon is that the white is overexposed, or much too bright, and the black is missing. Red, green, and blue are present.

 

[finkmac]

have you tried the auto colour and auto adjust options on the monitor?

 

[franklyn]

Yes

It do not help.

 

[franklyn]

May be I buy a new RamDAC chip but I think this do also not help ...?


The PLCC SMD Socket is bad, this type of sockets are always bad. Which bends in the middle see the picture, but it do not the problem I think ...

 

[olePigeon]

Are you sure it's not the cable adapter? I have several different ones that work with varying success.

 

[franklyn]

I will make a Test Adapter without the Green Signal to see if Sync on Green is the Problem? There is no english GrandVimage manual ...

 

[franklyn]

I ordered a new 110 MHz RAMDAC to try out. I'm also thinking about updating the ROM with the version from a 24-21 card. There's a soldered-on flash, an AT29C512 (64kx8). If it's large enough, I'd build an adapter cable from the 32-pin DIL pins/socket on the 21-19 card to my programmer, back up the old flash contents, and then install the larger version.

Or would that be done easier?

Does anyone have the 21-19 ROM contents for me?
(I have a VDR4 A21A V1.1.1.bin file but is it from a SE30 PDS card I think?)

 

[franklyn]

I try the card in a IIsi with System 7.1 and it has the same fault ...

 

[franklyn]

I built my own video adapter with separate sync and IDs set on a 21-inch multisync monitor. That was the problem. I'm now using a purchased adapter with the sync-on-green setting, and everything's fine now.

 

[franklyn]

The new SMD capacitor arrived today, and I soldered it in right away. These SMD capacitors are pretty rubbish to solder in manually, but I wasn't sure if a Tantalum capacitor could have been used? Except for the one for the DAC reference voltage, all the capacitors on the card are Tantalum capacitors, so the manufacturer certainly put some thought into this.

The new 110 MHz DAC is coming in the next few days, and I'm still missing the new ROM, and I'm still not sure how to update the 64k Flash.

I got the VDR4 A21A V1.1.1 from the forum here. I think it's from an SE/30 card. Now the question is, are the ROM versions the same for the different Bus models like SE/30,IIsi PDS, Nubus, and LC PDS?

 

[franklyn]

110Mhz RamDAC ...

 

[zigzagjoe]

Conceptually I would expect the ROMs to be similar but they don't auto-size RAM/detect DAC speed, you will need to figure out where the card information is stored. You should be able to compare my 21S dump to the 16S dump that's floating around to figure that out. Then apply a similar modification to the nubus ROM for your card & update the checksum.

If you're feeling adventurous I would expect the flash is in-system-programmable, so you probably can just write a tool to program it from within Mac OS if you're so inclined.

 

[franklyn]

In addition to the 64k Flash, there's also an EEPROM on the card, a NM93C46M8.

The first step would be to backup the original ROM from the 64k Flash in case something goes wrong. I don't know if that's possible, but I'm populating the 32-pin DIL socket and soldering an adapter to my programmer, a GALEP-4. To avoid damaging the programmer, I'm omitting the 5V power supply to the DIL socket so the programmer doesn't have to supply the entire Nubus card with power, and I'm powering the Nubus card via the computer.

Or does anyone have a better idea?

 

[zigzagjoe]

In addition to the 64k Flash, there's also an EEPROM on the card, a NM93C46M8.

The first step would be to backup the original ROM from the 64k Flash in case something goes wrong. I don't know if that's possible, but I'm populating the 32-pin DIL socket and soldering an adapter to my programmer, a GALEP-4. To avoid damaging the programmer, I'm omitting the 5V power supply to the DIL socket so the programmer doesn't have to supply the entire Nubus card with power, and I'm powering the Nubus card via the computer.

Or does anyone have a better idea?

Messing with that other eeprom doesn't seem be required at least on the PDS cards. See the posts I linked to here: https://68kmla.org/bb/index.php?threads/interware-grandvimage-24-21s-info-dump.45348/post-550045

I would sooner either remove the flash entirely and program it or write code to do it in-system. Trying to bodge something like you're suggesting sounds like a recipe for trouble.