Hey, all.
So I've got my PC Transporter installed in slot 7 of my IIgs ROM03, connected to an AppleColor RGB monitor by way of the ColorSwitch. And although all Apple II graphics modes display perfectly fine thru this connection, whenever the PC Transporter is engaged and switches to MS-DOS, the video starts rolling up the screen. Adjusting the VHOLD of the monitor does not fix the issue. Before anyone asks: Yes, I have slot 7 set to "Your Card" and I have tried using different slots.
Has anyone else had this issue and if so, do you have any suggestions for me?
Other than this severe problem, the PC Transporter is working fine: I can use DOS, I can run programs and games in CGA mode, et Cetera, and it passes its diagnostics too.
Thanks in advance,
Check the resistance values across each resistor on the ColorSwitch card.
If you have a normal CGA/EGA monitor and the cable for the Transwarp, see if it outputs video properly on that. This can help to eliminate if the issues is the ColorSwitch itself, and is a video output issue onthe PC Transporter.
I haven't used a PCT in 30 years, although I own two of them. :/
I've now tried the PC Transporter in a IIe via composite cable, and the rolling display problem is still there. So it is now confirmed as an issue with the PC Transporter itself, not the ColorSwitch. The IIe video is outputting just fine over composite. It's only when the PC Transporter takes over that the video gets goofy.
Any suggestions?
Are you connecting to the composite out jack on the PC Transporter?
http://osites.tripod.com/transport.html
Connector 3.
Are you using the original AE bootstrap/BIOS disks, and does the rolling begin prior to loading DOS?
A little video of this, showing every stage of your process to boot, might be useful.
Might be a bad crystal, or dead rsistors in the 16MHz circuit around the crystal.
Small note: Something that few people know about this card, is that there is no way to use it to play any IBM Joystick game. It does not sync with the Apple II joystickat--at all--and there is no connection that allows an IBM joystick to interface with it. If you want it to reduce clutter so that you can play DOS games, bear in mind that you will be limited to keyboard controls.
P.S. Found another thread on this same issue wih a PCT card from 2013:
https://www.reddit.com/r/apple2/comments/23ldhm/ae_pc_transporter_display_issue/cgymkqw/
A bit of insight, but no conclusion.
To answer your questions:
Yes, I am using the composite connection.
Yes, I am using the original disks.
The rolling begins as soon as the initial 40-column "PC TRANSPORTER" splash screen appears.
The PCB was thoroughly investigated, and I can now confirm that after replacing:
Capacitors = no change in behavior
Resistors = no change in behavior
Oscillator = no change in behavior
I have a sinking feeling it's a problem with one of the ICs. So I'm afraid it's irrepairable at this stage.
I'm posting about it here so that, in case anyone else has the same problem, they may not wish to waste their time replacing the same components on their own board.